## 1. Modern Research on Roger Bacon



There are two modern approaches to Bacon. The first is the study of
the physical, metaphysical, and related works of Bacon. Discovered in
1848 by Victor Cousin in Amiens MS 406, these works were edited by
Robert Steele and Ferdinand Delorme [OHI, 1905-1940]. With the
exception, however, of some new work on the teaching on the soul,
Bacon's concept of matter, the doctrine of
*experientia/experimentum*, and the doctrines of universals and
individuation, the doctrine of the heavens, and alchemy, the content
of these works has remained largely unstudied until the present time.
Indeed, one can argue that "critical" scholarly study of
these works has only just begun. In 2013, Silvia Donati made a
critical study of Amiens MS 406. She has presented solid arguments for
excluding three of the eight philosophical commentaries from the canon
of Bacon's works. They are the *Questions on the Physics
I-IV*, *Questions on Metaphysics XI*, and *Questions on
Metaphysics I-IV*. These three texts were commonly used in all
previous scholarship. And so, great care must now be taken in reading
the traditional scholarship on early Bacon where these works have
often been referenced.



The second and better known interpretation of Roger Bacon as a
scientist is found in nineteenth and twentieth century writers on the
history of science and has a solid basis in Bacon's own work,
e.g., the edition of the *Opus tertium* by J.S. Brewer [OQHI].
Bacon's *Perspectiva* (1267) [PRSP, 1996] presents a model
for an experimental science that ushered in a new addition to the
traditional *Quadrivium* (arithmetic, geometry, astronomy, music)
in the new universities of the Latin West, namely, the study of
optics. The university teaching text, "The Common Teaching on
Perspectiva," was written by Bacon's Parisian
colleague,John Pecham. We have critical editions now for the major
scientific works of Bacon. SISMEL at Florence, Italy now houses a
Roger Bacon research center. It has plans for future critical
editions. A new international society for the study of Roger Bacon,
*The Roger Bacon Research Society* has recently been
established. 



In 1859, William Whewell set the tone for this modern account of
"Roger Bacon and the Sciences" (Whewell 1858, p. 245). He
viewed Bacon as an advocate of experimentation ahead of his time. In
the late nineteenth century, Robert Adamson and many others
interpreted Bacon as a philosopher of science in the modern sense of
the term. This understanding of Roger Bacon did not begin in the
nineteenth century. Already in the late Renaissance, Francis Bacon had
characterized Roger Bacon as an exceptional figure among the
 schoolmen.[1]
 Francis held that Roger Bacon had set aside the scholastic
disputations of his age and engaged in the mechanical understanding of
the secrets of nature.



In the 1900s, Thorndike [LT1;LT2] and Duhem [LSDM, III, 442] asserted
that the role of observation in Bacon's science was minimal and
added nothing to his idea of a science. This modern read-back of
modern experimental method ignored the importance of optics in
Bacon's model for a science (Lindberg, 1997). In recent studies
(2006, 2012), Jeremiah Hackett has made explicit the manner in which
Roger Bacon served as a foil for Martin Heidegger's discussions
on the originality of modern science as a sign of Modernity. For
Heidegger, Bacon did not achieve the post-Galilean and Post-Cartesian
discovery of a mathematical projection of nature and the consequent
modern experiment. He claimed that it was false to argue, as many had
done between 1880 and 1940, that Roger Bacon was the source for the
post-Cartesian concept of science. One can argue for the uniqueness of
modern scientific method without setting aside the longue duree that
led to Kepler. One might note in passing that for Heidegger, Kepler is
the true forefather of modern science. In the post-World War II years,
A.C. Crombie (1953) argued that the "qualitative" aspects
of modern science originated at Oxford in the early thirteenth
century, specifically in the work of Grosseteste and Roger Bacon. This
interpretation received a critical response from Alexander
Koyre (1957) and others. Despite their significantly different
philosophical committments, Heidegger and Koyre both shared
Husserl's views on the distinctiveness of the modern
mathematical projection of nature as a condition for controlled
experimentation. This was seen as a distinctive new phenomenon, a
marker of modernity and something quite distinct from ancient and
medieval science. It was argued that Crombie read back some aspects of
modern scientific method into the works of Grosseteste and Bacon.
However, a recent study by Mattia Mantovani has signaled clear
connections between Bacon and Descartes' approach to vision and
perception (Mantovani 2020). 



Thomas S. Kuhn (1976), however, maintained that Crombie did identify a
real methodological connection between medieval and early modern
science. More recently, M. Schramm (1998) has argued that Bacon plays
a significant role in framing the context for the beginnings of
medieval, Renaissance and early modern notions of laws of nature. This
discusion has now been taken up for research by Giora Hon and Yael
Raizman-Kedar. The studies and editorial work of David C. Lindberg on
Bacon's natural philosophy, for example, the *De
multiplicatione specierum* [DMS] and *Perspectiva* [PRSP]
(1983-1996) have emphasized the need to read Roger Bacon as a
medieval scientist and not as an early modern or modern scientist.
Thus, it is as a medieval philosopher, scientist, and theologian that
he must be properly understood. Despite the polarity generated by two
separate modern traditions of interpretation, it should be noted that
there is some continuity between the interests of Bacon the
Aristotelian commentator and Bacon the writer on science.


## 2. Life and Works



Bacon remarks in the *Opus tertium* [OQHI], written c. 1267 that
he had devoted forty years to study since he first learned the
*alphabetum* and that no other scholar had worked as much in the
Arts and Sciences as he. Some scholars use this text to argue that
Bacon was writing about his elementary education and therefore that
was born c. 1220 [Crowley (1950), Easton (1952), Lindberg (DMS,
1983)]; others hold that he was writing about his early university
education - *Alphabetum philosophiae* is a term Bacon uses
in the chapter from which the following cited text is taken -
and thus that he was born c. 1214 [Little (RBE, 1914), Maloney (CSTM,
1988), Hackett (2016), Molland (2004)]. The text reads:



> 
> 
> I have labored much in sciences and languages, and I have up to now
> devoted forty years [to them] after I first learned the
> *alphabetum*; and I was always studious. Apart from two of these
> forty years I was always [engaged] in study [or at a place of study],
> and I had many expenses just as others commonly have... And it is
> known that no one worked in so many sciences and languages as I did,
> nor so much as I did. Indeed, when I was living in the other state of
> life [as an Arts Master], people marveled that I survived the
> abundance of my work. And still, I was just as involved in studies
> afterwards, as I had been before. But I did not work all that much,
> since in the pursuit of Wisdom this was not required. ([OQHI], 65)
> 
> 
> 



Some time after 1248, he set aside the common scholastic ways of
teaching in order to devote time to languages and experimental
concerns. Thus, we can see the period from c. 1240-48 as the
time during which he lectured at Paris on Aristotle, on Grammar/Logic,
and especially on the mathematical subjects of the *Quadrivium*.
And so, depending on the chosen year of birth, the chronology would be
as follows: (1) Bacon was born c. 1214, educated at Oxford c.
1228-36, Master of Arts at Paris c. 1237-47/8, Private
Scholar 1248-56/7, active again at Oxford c. 1248-51, back
in Paris 1251, Franciscan Friar at Paris c. 1256-57 to 1279,
returning to Oxford c. 1280, died c. 1292. Or: (2) Bacon was born c.
1220, educated at Oxford c. 1234-42; Master of Arts at Paris c.
1242-47/8, active again at Oxford c. 1248-51, back in
Paris 1251, Franciscan Friar at Paris 1256/7 to 1279, returning to
Oxford c. 1280, died c. 1292. Further precision on the chronology must
await the critical edition of all the works of Roger Bacon and careful
scientific study of these works in relation to other thirteenth
century scholars.



The Aristotelian *Quaestiones* are to be found in a single
manuscript, Amiens MS Bibl. Mun. 406. The materials found in this
manuscript include two sets of questions on the *Physics* and two
sets of questions on the *Metaphysics* of Aristotle, the
questions on the *Liber de causis*, and the Pseudo-Aristotelian
*De vegetabilibus*. As noted above, three of the questions on the
Physics and Metaphysics can now be excluded from Bacon's canon.
A new version of Bacon's second set of questions on the
*Physics* inter-textually excerpted by another thirteenth-century
author has recently been identified by Silvia Donati in Philadelphia
MS Free Library, Lewis Europe, ff. 77ra-85rb (Donati 1997). This is an
important discovery that has enabled scholars for the first time to
carry out a critical-textual study of Bacon's works on
Aristotle's *Physics* in the context of the development of
English natural philosophy in the period 1240-1300.



The early logical works consist of the *Summa grammatica*,
*Summa de sophismatibus et distinctionibus* and the *Summulae
dialectices* [=*Summulae super totam logicam*]. These works
show that Bacon is indebted to the teaching of logic at Oxford and
Paris in the 1230s and 1240s. They have received much critical study
in recent years. They reveal Bacon as a mature philosopher of logic
who is representative of terminist and pre-modist grammar and logic.
Bacon's writings on grammar and logic have a connection with the
Oxford ascribed *Logica cum sit nostra* and with the works of
William of Sherwood. The logical works are clearly influenced by the
teaching in Paris of Robert Kilwardby. They give evidence of Bacon as
a philosopher who connects the *Logica modernorum* with new
logical and philosophical problems based on the natural philosophy and
metaphysics of Aristotle as commented on by Avicenna and Averroes.



Alain de Libera has argued that the *Summulae dialectices* is
typical of mature works in the philosophy of logic c. 1250 and a
little later. If this is the case, can we exclude the possibility that
Bacon continued teaching at some University up to ca. 1256/57? He does
say that he had a reputation as a scholar and teacher up to that time.
Scholars have long held that Roger Bacon was a pioneer in the
introduction of the study of Aristotle as interpreted by Averroes and
Avicenna to the University of Paris c. 1240. But to this we must add
the name of Solomon Ibn Gebirol (Avicebron). During the past ten years
or so, research has shown that two Erfurt manuscripts (Amplon. Q. 290
and Q. 312) ascribed to Walter Burley (1274/5-1344) by the
Amplonius de Berka in the fifteenth century, actually belong to the
first half of the thirteenth century. Rega Wood, the editor of the
*Physics* from the Erfurt MS Amplon. Q 290, has attributed these
questions on the *Physics* and most of the other works in these
two Erfurt manuscripts to Richard Rufus of Cornwall, a contemporary
and opponent of Roger Bacon [Wood 1997; Wood, IPA, 2003].



Recently, it has also been demonstrated that as Master of Arts at
Paris during the period of the First Averroism (c. 1240-48),
Bacon had confronted and reviewed some of the major issues concerning
the Latin Averroism which eventually produced a major crisis at Paris
in the period 1266-77 (Hackett 2005). And, as we will see below,
Bacon, in his works from the 1260s, will revisit these topics.



Bacon joined the Franciscan Order about 1256/7; whether he did so at
Oxford or Paris is not known. At any rate, he was probably in Paris in
the late 1250s and was definitely there in the early 1260s. He had
been attracted to the Order by the philosophical, theological, and
scientific example of Grosseteste, Adam Marsh, and other English
Franciscans. He had personally known Adam Marsh at Oxford c.
1248-51. Because of their over-emphasis of a purported
condemnation of Bacon c. 1278, scholars had tended to ignore or tone
down Bacon's very real commitment to his Franciscan way of life.
The past ten years have seen new work by Amanda Power (2013) and
Timothy J. Johnson (2009, 2010, 2013) emphasize the compatibility of
Bacon's concerns c. 1266 with the mission of the Franciscan
Order as presented by Bonaventure and the Franciscan School at Paris.




In answer to the Papal Mandate received in July 1266, Bacon produced
some very significant works. The *Opus maius*, *Opus minus*,
and the related foundational work in natural philosophy, *De
multiplicatione specierum*, the work on burning mirrors, *De
speculis comburentibus*, together with an optical lens, were sent
to the Pope c. 1267-68. They were seen as a preamble to a
proposed major work on Philosophy. It remains a question as to whether
the *Opus tertium* was sent. Together with these works in the
1260s, Bacon produced the Preface to the Works for the Pope,
*Communia naturalium*, *Communia mathematica*, *Epistola
de secretis operibus naturae et de nullitate magiae*.



Amanda Power (2013) has provided a masterful interpretation of the new
context of Bacon's post-1266 works for Pope Clement IV. She
places Bacon in a Franciscan context within the wider mission of
Christendom in its relations with other cultures and religions. The
*Compendium studii philosophiae* can be dated to about 1271. This
latter is a largely polemical work on the state of studies at Paris
and an apology for his scholarly situation. It does, however, contain
an important section on his theory of language and translation. He
completed the edition of the important work on medieval politics and
statecraft, the *Secretum secretorum*, at Oxford some time after
1280. It is clear that by 1266 and later, this important work played a
major role in Bacon's understanding of the political uses of the
experimental sciences. He also produced an important work on the
calendar, the *Computus*. The *Compendium studii theologiae*
is usually dated c. 1292, but its content does not differ from the
concerns of the work in 1266. 



One must bear in mind that Roger Bacon in the 1260s is writing as an
individual author for a patron, Cardinal Guy le Gros de Foulque (Pope
Clement IV, 1265-68). A onetime Master of Arts, he was no longer
a teaching Master at the University of Paris. This gave Bacon the
freedom to address both philosophical (Aristotle) and theological
(Augustine) issues in a manner denied to teachers in the Faculty of
Arts, who were limited for the most part to disputations on the texts
of Aristotle. He writes self-consciously as a representative of the
text-based practices of Robert Grosseteste and in opposition to the
new "sentence-methods" of the schools of theology. His
polemical writings ca. 1267-68 are centered on the struggles in
the Arts and Theology at Paris. The Pope instructed Bacon in 1266 to
ignore the rules of his Order and to send him his remedies about
matters of some importance. It would appear from the context of
Bacon's works for the Pope that the remedies had to do with
educational matters at Paris, which at this time was the foremost
university of the Christian commonwealth. The remedies sought must
also have concerned geo-political matters as well as the exigencies of
Christian missions. 



The reception of the life and works of Roger Bacon is complex. Each
generation has, as it were, found its own Roger Bacon. Another study
by Amanda Power (2006) has provided a thoughtful account of the
complex reception of Roger Bacon in England and of the extent to which
the image of the *Doctor Mirabilis* is often colored by the
changing controversies of the present down through history.


## 3. Bacon's early work on Grammar and Logic



Bacon has a complex notion of grammar. It ranges from the elementary
teaching of Latin through "rational grammar" (linguistics)
to a knowledge of the sacred "Wisdom" languages. It is
also connected with a theory of signs and with the *vis
verborum*, including the magical power of spoken language. One
notices continuity between Bacon's early works on grammar and
logic and his later works after 1260 on the theory of signs (*De
signis*).


### 3.1 *Summa grammatica*



In this work, Bacon draws directly from the commentary on Priscian
(*Priscianus minor*) by Robert Kilwardby. This is representative
of early speculative grammar as it developed in Paris during the first
half of the thirteenth century. Bacon's approach to grammar and
logic has a connection with the logic of that of William of
Sherwood..



Part one of the *Summa Grammatica* sets out the rules governing
both common constructions with subject and verb and rules governing
figurative constructions. The latter include specific accounts of the
five figures of construction: antithesis, synthesis, prolepsis,
syllepsis, and zeugma. This is borrowed from Kilwardby
(*Institutiones grammaticae*, xvii, 153). In part two, Bacon
analyzes the more difficult non-figurative constructions such as
impersonals, gerundives, ablative absolutes, interjections. In a third
part, he examines sophisms in terms of their subject-matter and ranges
from a cursory treatment to more extended treatments typical of a
disputed question. In the last section, there is a cursory analysis of
some short sentences including adverbial constructions [*lupus est
in fabula*] and some liturgical formulae [*patris et filii et
spiritus sancti, ita missa est*]. The latter are problematic due to
their elliptical character. An account of Bacon's intellectual
relationship to Robert Kilwardby can be found in Irene Rosier
(1994).



As noted above, a major feature of this treatment of speculative
grammar is the fact that the reasoning is closely linked to the
*Physics* of Aristotle (Rosier
 1994).[2]
 This reasoned grammar is based on the belief that "art imitates
nature to the extent that it can" (*Physics* II, 219 4a
21). Borrowing from Aristotle and Averroes and influenced by Robert
Kilwardby, Bacon exploits the distinction between the permanent and
the successive as the ground of the grammatical distinction between
the noun/pronoun and the verb/adverb. He applies this to the
definition of grammatical category.



As Irene Rosier-Catach has noted, "The construction of
words is conceived as a movement. The verb, the pivot of the sentence,
signifies action and movement and needs for that reason two terms, a
*terminus a quo* or *principium* and a *terminus ad
quem* or *terminus* (*Summa Grammatica* 66, 78). On one
level, physical conceptualization is used to re-define certain
notions. Cases are properties allowing an expression to function as a
term of movement (*Summa Grammatica* 34); in this way, the
accusative expresses the *terminus ad quem*. At a second level,
Bacon's conceptualization allows him to state some very general
rules for the combination of categories" (Rosier-Catach 1997,
70).



For example, Bacon argues that both the participle and the infinitive
by means of their verbal signification are not sufficiently stable to
be a *terminus of motion*. This is based on the premise that
"nothing which is in motion can come to rest in something in
motion, no motion being able to complete itself in something in
motion." And, using the principle that "the action is in
the patient as in a subject," he tackles the issue of
grammatical agreement. Further, the central principle for the
organization of terms is the notion of dependence
(*dependencia*). Hence, the relation of natural dependence
between the accident and the subject is reflected in the construction
of the adjective with its substantive.



Grammatical reasoning, then, finds itself wedged between physical and
logical reasoning. This can be seen in the analysis of the expression,
*est dies*. Why one term and not two? What is the function of
*dies*? In an analysis of motion there are two terms. But in
reason, one can see that the one term has two functions that are
necessarily present in every assertion. And whereas Logic requires
that the subject be different from the predicate, Grammar as a
positive science depends on the intellect and will. 



The most significant aspect of Bacon's grammatical analysis is
one that will be replicated in his later work on semiotics. This is
his *intentionalist* analysis. The reasons connected to
grammatical analysis cannot be discovered or applied mechanically:
they are dependent on the signifying intention of the speaker
(*intentio proferentis*). This kind of analysis is found in
Robert Kilwardby and in many similar texts on sophisms. As
Rosier-Catach puts it, "The correctness of a statement does not
depend solely on its conformity with the *rules of grammar* but
equally on its adequateness with its signifying intention. Sometimes
indeed, because the speaker *wishes to signify* some precise
idea, he may legitimately distance himself from the normal
rules" (Rosier-Catach 1997, 73). Still, this freedom is not
absolute; it must be justified linguistically. Even elliptical
expressions such as *ita missa est* have within them the
capacity to allow further application of formulas such as *cantata,
dicta*, etc. Thus, to quote Rosier, "The rule-governed
nature of language-functions is to be found not only in the common
usage but also in those 'authorized' variations. It is
precisely this principle that Bacon will put to work at the semantic
level when he conducts his analysis of *Signs* [c. 1267].
Beyond the ordinary usage of the sign, derivable from its institution,
the speaker always has the liberty to use it in the
*translated* way, the variation being in the majority of cases
explainable and for this reason comprehensible by the listener. In
other words, language is for man an instrument, a means. This
voluntarist/instrumental conception is to be seen likewise in the
context of Bacon's treatment of the magical power of
words" (Rosier-Catach 1997, 73-74).



This imporant aspect of "the magical power of words" has
again been examined carefully in terms of language study as it relates
to the uses of logic in theology by Rosier-Catach (2004). Graziella
Federici Vescovini (2011) has now presented a magisterial study of the
close connection of philosophy and natural magic in the Middle Ages,
accentuating the notion of "the magical power of words" in
relation to Bacon and other medieval philosophers. This magical power
of words, derived from Alkindi, has a connection with Bacon's
theory of communication in part five of the *Moralis
philosophia*.



> 
> Bacon's Logic (1240s):
> 
> * *Summa de sophismatibus et distinctionibus* (SSD)
> * *Summula super totam logicam* (= *Sumulae
> dialectices*) (SD)
> 
> 
> 



The late Jan Pinborg has described the terminist logic found in Bacon
and his contemporaries as "semantical analysis of a natural
language, viz. Latin, built on Aristotelian logic, especially the
*Sophistici elenchi* and the *Peri hermeneias*, and on
the development of grammar. This analysis stressed the truth value of
propositions analyzed and its conditions, and therefore displayed what
can be called *a contextual approach*; that is, it was based on
the actual function and reference of the term in the proposition to be
analyzed. A given word could be used differently, or according to
different *suppositions*, and the rules for these different
uses helped to avoid ambiguities. The doctrine of supposition was
intended to solve both the relatively trivial ambiguities which arose
from confusion of linguistic levels (man is white, man is a species,
man is a noun) and ambiguities involved in quantification (or
distribution) theory. These problems were primarily solved in terms of
reference, since different *suppositiones* picked out different
ranges of individuals."(Jan Pinborg 1979)



One can see therefore why Bacon, through his concern with the central
role of applied logic in guarding against ambiguity, saw the analysis
of equivocation as central to the analysis of language. Against the
growing Modist tendency to understand parts of grammar as indicative
of the objective constituents of things in the world, Bacon stresses
the importance of equivocation analysis. Since the imposition of
names, the constant change in language use, and especially the ongoing
implicit shift of meaning in language are all important for a theory
of meaning, Bacon demands contextual language analysis. Here, one
might speak of Bacon's "pragmatic" approach to
language theory.


### 3.2 *Summa de sophismatibus et distinctionibus* (SSD)



Alain De Libera has provided a very precise summary of Bacon's
place in the history of logic and especially of the two early works
just listed. He remarks:



> 
> 
> The *SSD* belongs to a literary genre found in Paris during the
> first half of the thirteenth century, the *Distinctiones
> sophismatum*. It compares with the *Tractatus de
> distinctionibus communibus in sophismatibus accidentibus*
> attributed to Matthew of Orleans, the *Distinctiones
> 'notandum'*, the *Abstractiones* of Hervaeus
> Sophista, the tracts on *Distinctiones sophismatum* as well as
> 'anonymous' treatises described by De Rijk and Braakhuis.
> Briefly, the *distinctiones* have the task of listing the rules
> to be used in the practice of sophisms and setting out the context,
> while the *syncategoremata* set out the logical conditions for
> the proper use of syncategorematic words. (De Libera 1997,
> 105-106)
> 
> 
> 



Generally, the SSD deals with problems of universal quantification, as
for example the uses of the word *omnis* ('all').
Bacon pays close attention to words that present philosophical
difficulties, such as 'infinite', 'whole', and
'negation'. The common logical topics are covered. Still,
Bacon shows some originality in his treatment of
'inclusion' or 'scope' in quantification. He
also develops the outline of what will become his own contribution in
the 1260s, i.e., his analysis of a "production of speech".
Bacon develops this analysis to deal with sentences such as
'Every animal is either rational or irrational'. Here, his
contemporaries invoked a theory of natural sense to account for the
provision of semantic information on the basis of the order of the
presentation of the terms. But Bacon insists that one must take into
account (a) the signifying intention of the speaker, (b) the
linguistic expression, and (c) the sense that the listener provides.
Bacon presents two basic positions: an expression must have parts that
enable the hearer to make an interpretation that will correspond with
the intention of the speaker. Thus, the actual expression alone is
necessary but not sufficient for an account of the meaning. A
linguistic analysis that involves speaker/hearer/expression is also
required.



The expression of the proposition alone is accidental and thus
contains only a relative sense. Further, the linear order of the
expression does not provide the listener with enough information about
the logical form. Knowledge of the logical form requires reference to
the mental proposition. This implies that every mental proposition,
for both speaker and listener, is an *interpretation*. The
meaning of any statement is a function of the understanding. This
presentation of the speech act prepared the ground for Bacon's
mature theory in his post-1260 works, the *De signis* (DS),
*Compendium studii philosophiae* (CSP), and *Compendium
studii theologiae* (CST).


### 3.3 *Summulae dialectices* (SD)



De Libera has placed this work at Oxford c. 1250, but notes the
presence of Parisian teachings in the text. The title given in the
Seville MS, *Summulae super totam logicam*, provides a better
sense of the nature of the work. To summarize De Libera, this is the
mature work of a practiced teacher, not the work of a beginner. It is
ahead of other works of the 1240s in the skillful manner in which it
examines Aristotle and other newly translated works in philosophy and
science. The work is important for two new semantic positions: (1) the
doctrine of univocal appellation and (2) the doctrine of "empty
classes" in predication. For Bacon, a word cannot be applied in
a univocal manner to both an entity and a non-entity. This position
will provide Bacon with a basis for his attack on Richard Rufus of
Cornwall in his works after 1260, and especially in the *Compendium
studii theologiae* (1292). This attack was not targeted at Rufus
alone; it is written in opposition to the common teaching of the time
at Paris, according to which a word has a natural meaning and once
that meaning is given, it remains a constant. For example, the term
'Caesar' can cover both the once living Caesar and the now
dead Caesar. Bacon rejects this on the grounds that for him, terms are
imposed on "present things" and there is nothing in common
between an entity and a non-entity or between the past, present, and
future. Hence, Bacon is opposed to the notion of "habitual
being". Thus, terms have present appellation and their reference
to the past and future must be accidental. For Bacon, name and
signification are imposed on the present object, and these are opened
to past and present on the basis of verbal tense. One might call it
"supposition through itself for present things". Another
important aspect of SD is the complex theory of determination found in
the composition and division of the propositional sense.



The theory of imposition is fundamental to Bacon's approach
(Rosier & de Libera 1986; Rosier 1994, 123-156).
This allows for explicit and tacit changes of imposition of meaning in
communication and points to the need for linguistic analysis and
careful study of context in order to be strict about univocal meaning.
Likewise, an interest in overcoming equivocation and ambiguity figures
throughout Bacon's logical works. Words can, indeed, be extended
'metaphorically' to cover non-existing things. In this
work of Bacon, one finds a combination of influences from both the
Oxford terminist logic and the Parisian pre-modist grammar of the
1240s.



The reader can easily see that this treatment of "all of
logic" corresponds to a large extent to what is found in many
'modern' logic books prior to the treatment of predicate
logic. It would be useful to show the extent to which Bacon's SD
provides a template for later works on the totality of logic, such as
the *Summa Logica* of William of Ockham and subsequent texts up
to modern times.


## 4. Bacon as an Aristotelian Commentator


### 4.1 Roger Bacon and Richard Rufus: *In physicam Aristotelis*



Richard Rufus and Roger Bacon were two of the earliest Teachers of
Aristotle's natural philosophy and metaphysics at Paris, c.
1235-50. The recent publication of Richard Rufus of
Cornwall's *In Physicam Aristotelis* has made available
what is certainly a very important text for an understanding of the
influence of Aristotle's *Physics* on the early tradition
of English natural philosophy in the thirteenth century (IPA 2003).
Richard Rouse has dated the text of these *Physics* questions
"on the early side of the middle of the century" (Wood,
IPA Introduction, 33). Silvia Donati and Cecilia Trifogli have mapped
out the complex tradition of named and 'anonymous'
commentaries on Aristotle's *Physics* in 13th century
England. (Del Punta, Donati & Trifogli 1996; Trifogli 1997, Donati
1997; Trifogli 2000). As noted above, Rega Wood ascribes the text to
Richard Rufus of Cornwall (died c. 1260). She claims that
"Richard Rufus was the earliest Western teacher of the new
Aristotle whom we know." He taught Aristotelian physics and
metaphysics as a Master of Arts at the University of Paris before
1238. In the apparatus of the edition, Wood notes that these comments
on Aristotle's *Physics* were later taken up by Roger Bacon
in his *Questiones* on Aristotle's *Physics*, and as a
result, she sees Roger Bacon as Richard Rufus's successor as a
Parisian teacher of Aristotle's natural philosophy. As evidence
for the influence of Rufus on Roger Bacon, Wood presents a discussion
of three topics: (1) projectile motion, (2) the place of Heaven, and
(3) the beginning of the world (IPA, 12-28).


### 4.2 Bacon and Grosseteste: Knowledge, Science and Intuition



Bacon holds that scientific knowledge is twofold: first, there is the
"imperfect and confused knowledge" by which the mind is
inclined to the love of the good and of truth. This implicit knowledge
is innate. Second, there is explicit rational knowledge. One part of
this has to do with the knowledge of the principles of science; the
other is the knowledge of conclusions. This latter is complete
knowledge though it is not exhaustive. Bacon's account of sense,
memory, and experience is more extensive than that found in
Grosseteste's *Commentary* and reflects his own reading of
Avicenna, the medical tradition, and works on optics. Bacon
distinguishes *experientia* from *experimentum*. Experience
(*experientia*) is the distinct knowledge of singular things, and
all animals have this distinct knowledge of singulars. But not all
animals have *experimentum*, that is, a science of principles
based on experience. As he puts it, "experience is the distinct
reception of singulars under some aspect of universality, as is stated
in the text [of Aristotle], but only the universal is grasped by the
intellect." Therefore, only humans and not other animals have
experience [*experimentum*] ([OHI, XI] 16). Many animals have an
image (*imaginatio*) of singular things and live by innate art
and industry, naturally knowing how to adapt to changing weather
conditions. Human art, however, is acquired and is a science of
principles based on experience (*experimentum principium*).



One can express Bacon's position as follows: *experimentum*
is the universal source for our discovery of scientific principles.
Scientific knowledge, once established, proceeds by demonstration.
*Experientia* designates the simple perception of singulars. Only
in a very loose sense can it be used of scientific knowledge.
Sometimes, however, these two terms about experience are used
interchangeably. In this account, Bacon has not yet come to his later
notion of a *scientia experimentalis*, and the experimental
verification (*certificatio*) of the conclusions of demonstrative
knowledge (ca. 1267). He is dealing only with experience as the source
of the principles of our knowledge of art and science.]



In other words, at this stage, Bacon is mainly concerned with
Aristotle's definition of experience in the *Metaphysics*
and *Posterior Analytics*, although one already notices that he
relates the Aristotelian subject matter to the discussion in
Alhacen's *Perspectiva*. Nevertheless, it is also important
to note that these Aristotelian concerns with *Experimentum*
are repeated in 1267 at the beginning of *Opus majus*, Part Six
on exprimental science, and thus, Aristotle's
*Metaphysics*, *Posterior Analytics* and *Meteorology*
together with the *Optics* of Ibn al-Haytham will form the
necessary philosophical background for Bacon's laterc. 1266
notions of the experimental sciences.


### 4.3 Bacon on Matter



In the later (post 1260) *Communia naturalium*, Bacon gives six
meanings for the concept of matter. (1) Matter is the subject of
action as when we say that wood is the matter for the action of the
carpenter. (2) In the proper sense of the term, matter is that which,
with form, constitutes the composite, as in the case of every created
substance. (3) Matter is the subject of generation and corruption and
has the property of being an incomplete and imperfect thing in potency
to being a complete thing. (4) Matter is the subject of alteration
since it receives contrary accidents. (5) Matter can be considered as
an individual in relation to the universal, the latter being founded
in its individual as in a material principle. (6) Matter is the name
for that which is gross, as when we say that earth has more matter
than fire (Sharp 1930, 127-151).



Form has a certain priority to matter as the end of generation and as
the perfection of the material principle. It is the principle of
action and of knowledge. In general, for Bacon, matter is not a mere
potency. It is an incomplete something (substance) and so for him
matter and form are two incomplete substances that integrate to make
one *individual* substance. In this one has a notion of matter
as in some sense a positive thing. It is not a nullity. One way to
place Bacon's position on matter is to situate it between the
material monism of David of Dinant and the position of Aquinas that
matter is a pure potentiality. For Bacon, matter as a being of essence
(*esse essentiae*) has being in itself. For Aquinas, form alone
gives being. But for Bacon the being of essence and existence belong
together. Matter, therefore, can be a principle of division. Unlike a
monist position, Bacon stresses the plurality of matters. The relation
of universal and particular with respect to matter and form in Bacon
is complex. One notes the influence of Avicenna. 



In both early and later works, Bacon objects to the idea that matter
is one in number in all things. The background to this issue arises in
the 1240s to 1270s of the *Fons vitae* of Avicebron (Solomon
Ibn Gebirol) and from Franciscan discussions at Paris on the nature of
the unity of matter. Bacon holds that matter "is not numerically
one, but in itself and from itself it is numerically distinct in
numerically different beings." Still, he does not object to a
logical unity of matter. For example, matter as potentiality is the
original source of the being of contingent things. This is the
non-being of the creature in contrast with the being of the Creator.
Matter properly speaking is prime matter. This must be distinguished
from both natural matter and from artificial matterThus, Bacon will
speak of the matter of both corporeal and spiritual beings, and hence
of "spiritual matter," a concept that Aquinas found to be
contradictory.

 The importance of this hylomorphism in the
Franciscan school at Paris has been examined by Anna Rodolfi (2010,
2014). And the complexity of natural matter with reference to
generation and also to alchemical process has been set out with care
by Michele Pereira (2014). Bacon's doctrine of matter as a
source for the theory of matter in Peter John Olivi has been noted by
the editors of *Pierre de Jean Olivi Sur le materie* (2008).
Bacon's extended account of matter in his early and later works
is very significant for the late thirteenth and early fourteenth
century discussions of the concept of matter.


In his later works, and specifically in his works on natural
philosophy, Bacon presents nature as an active agent. The form or the
species is the first effect of any natural agent. The power of the
species educes the emergence of the thing from the potency of matter.
It does not simply produce a form/species and impose it on the matter.
Matter has an *active potency*, and this is actualized due to
the action of the natural external agent. See Michela Pereira,
"Remarks on materia natualis". 


### 4.4 Bacon on Universals and Individuation



Bacon has two distinct treatments of universals and individuation: his
early works (1240s) and later in the *Communia naturalium*
(1260s-70s). 



In the works from the 1240s, Bacon distinguishes the *real
universal* from the *mental universal*. Hence, the
universal as the ultimate basis of predication is not the species as
mental intention. Universals in the primary sense as the basis of
scientific objectivity are extra-mental. Bacon's presentation of
this issue is complex. Certainly, he is not a complete Platonist in
regard to universals. To the objection that since form is individuated
through its matter and whatever exists in things must exist in matter
as individuated, but the universal is not such a thing, he replies
that a universal is either in the mind or in things; if it is not in
the former, it has to be in the latter. A universal arises from common
matter and common form and so has no need of being immediately
individuated: "And because the common matter and common form
exist along with the proper matter and form of individuals, the
universal is present in this way in singulars" ([OHI, X]
242-243 = TTUM, 36). Hence, one cannot split apart the common
matter from the particular matter or the common form from the
particular form of a particular individual.



In one question, Bacon rejects the view that universals are
constituted only by the mind. He holds that the universal in and of
itself is prior to the knowledge process: "This follows because
a universal is nothing other than a nature in which singulars of the
same (nature) agree; but particulars agree in this manner in a common
nature predicable of them, without any act of the mind" ([OHI,
X], 242-243 = TTUM, 36). This sounds Platonic, but in fact for
Bacon there are no Platonic universals in a separate world; rather,
real universals do exist, but they are found only in and with
individual things. There is a mutual interpenetration of common form
and matter and proper form and matter such that there is just one
individual, and so the common nature is realized in this or that
individual. Bacon's answer to the possibility of a universal
being present in a singular is stated as follows:



> 
> 
> Only three kinds of being are imaginable: either [being] in and of
> itself, [being] in the mind, or [being] in things, but a universal is
> not something that has being in and of itself and stands on its own,
> because then it would be a Platonic idea; neither [does it have being]
> in the mind, as we have seen... Again, a universal is a common
> nature in which particulars agree; but Socrates and Plato and [others]
> of this sort cannot agree in a common nature which is in them unless
> the nature [be] in some way duplicated in them, because a universal is
> nothing other than a common nature extended into particulars and
> existing in them as duplicated, in which all things truly exist. And
> thus, without them [the particulars] there can be no
> universals.... ([OHI, VII, 243-244 = TTUM, 37)
> 
> 
> 



For Bacon, there are two kinds of particular, the determinate here and
now particular and the indeterminate particular.



Bacon treats the problem of individuation both in the early Parisian
lectures and the later *Communia naturalium*. This has given
rise to the issue of Bacon's realism or his proto-nominalism.
Itis addressed in the next section.


### 4.5 Bacon's Realism: On the Way to Late Medieval Nominalism?



In the light of the foregoing, a key issue arises in his early works:
even if Bacon disclaims being a Platonist with regard to universals,
he is clearly a strong external realist. This realism is continued in
the *Communia naturalium* [OHI, 2-4] but with certain
important qualifications. This polemical account of the discussion of
Aristotle in the 1260s is understood by Bacon as an aid for the study
of theology. And now, it is clear that for Bacon, in the intention and
execution of nature, *the individual has definite ontological
priority over genera and species*. His account becomes an attack
on contemporary positions influenced by Albertus Magnus that would
subordinate the individual to the universal. Species and genera are
there for the sake of the production of the individual. He states,
"In no other field are the authorities in such
disagreement." Even Aristotle seems to contradict himself. Bacon
finds a correct answer in the *Metaphysics* of Avicenna:



> 
> 
> There are two kinds of nature, universal and particular, Avicenna
> teaches in the sixth book of [his] *Metaphysics*.
> 
> 
> 



Bacon adds,



> 
> 
> Universal [nature] is the governing force of the universe [and is]
> diffused among the substances of the heavens [and] throughout all the
> bodies in the world; it is [that] in which all bodies agree and
> through which all are maintained at a certain general level of
> perfection and well being. This universal nature is the corporeal
> nature that is designated in the second genus, which is [that of]
> body, and this nature excludes all incompatible things which are
> abhorrent to the whole universe, such as a vacuum. ([OHI, II], 92 =
> TTUM, 85-86) 
> 
> 
> 



We see then that Bacon understands universal nature as supervening on
a world of distinct individual natures such that corporeal action is
contiguous and that a vacuum is excluded. The "particular
nature" is the directing power of the species with its
individuals, and is divisible into the directive power of the species
and of the individual. The example he gives is from embryology: there
is the directing power of the species intending the production of the
human in general; it intends the production of the individual
accidentally. And there is the directing power of the individual,
which aims at the determinate individual human as such and mankind in
general. As he puts it, "the universal is prior to the
particular in [both] the work and execution of nature, but is
posterior in intent" ([OHI,II], 93 = TTUM, 87). He then states
the ontological priority of the individual over universals as
follows:



> 
> 
> But if we would speak about the universal nature that is the directing
> power of the universe, [we should say that] it intends and brings
> about *an individual first and principally*, about which there
> is mention in the *Book of the Six Principles*. Nature operates
> in a hidden manner in things: once a determinate man is generated, man
> as such is generated. And the cause of this is that *one individual
> excels all universals in the world, for a universal is nothing but the
> agreement of many individuals*. ([OHI,II], 94, = TTUM, 86)
> 
> 
> 



He distinguishes *the absolute nature of an individual* as
something absolute, that is, "that which constitutes it and
enters its essence." This absolute nature of an individual is
ontologically more important than that by which one individual has
some agreement with another. One can notice that Bacon is now writing
as a person with a theological interest: "And because all the
things which I am treating are for the sake of theology, it is clear
through theological reasons that a universal is not [favorably]
compared to singulars. For God did not make this world for the sake of
universal man, but for singular persons...Therefore, speaking
plainly and absolutely, we must say that an individual is prior in
nature [to a universal] both in operation and in intent," and so
"...it is necessary that the ranking according to prior and
posterior be denominated absolutely and simply from the governing
power of an individual..." ([OHI,II], 94-95 = TTUM,
88-89). Bacon knows that he is defending a position in rank
opposition to the common view: "Since the whole rabble [at
Paris] holds the contrary position, because of certain authorities,
the views of the latter must be presented" ([OHI,II], 96 =TTUM,
90).



This account has given rise to opposing interpretations. Theodore
Crowley (1950) saw in these passages the beginnings of late medieval
nominalism that would find its expression in William of Ockham. Thomas
S. Maloney (1985) challenged this reading and argued that the later
Roger Bacon, like the earlier Bacon, was not a nominalist but an
extreme realist. More recently, Chiara Chrisciani has argued that
already in 1964, Camile Berube saw Bacon as the originator of the
Franciscan doctrine of the direct intellectual perception of the
singular. He also noted the link between Bacon and William of Ockham
even though the path of influence was long and complex. She also
correctly noted that for Bacon, we have a sense-perception of
universals, one quite different from his contemporaries. Following K.
Tachau and Y. Raizman-Kedar, Crisciani argues that the universals are
materially embodied in the intellect. In a recent study, while
agreeing with this position with respect to the material intellect, I
argued that it needed qualification. Perhaps we should hold that there
are elements of both 'extreme-realism' and
proto-nominalism in this account in the *Communia naturalium*. In
his important essay on individuation in the fourteenth century, Jorge
J.E. Gracia (1991) argues for seeing this text and others as the
beginning of the strict tradition of late medieval nominalism.


### 4.6 Bacon on Body, Soul and Mind: Early Works



Bacon understands the soul to be a spiritual substance in union with
the Body. At this early stage, he does not hold the Avicennian notion
of a separate agent intellect. In union with the body, the soul has
two intellects, potential and agent. The former is directly connected
with the sensitive powers and the object of this intellect is the
singular material thing. The agent intellect is directed upward and
knows spiritual beings in its own essence. For Bacon, there is a kind
of confused innate knowledge in the soul. This is not a Platonic idea.
It is more like a disposition that inclines the soul towards knowledge
of the truth. Still, it is in some sense an innate knowledge of the
first principles of knowledge. The agent intellect illuminates the
images and frees them from specific material conditions. The
universals are then impressed on the potential intellect.


### 4.7 Bacon on Body, Soul, Mind: Later Works



In his *Communia naturalium*, Bacon explains that he wrote his
account of sensation, the sensitive soul, and perception in the
*Perspectiva* as a criticism of the common teaching of the
Aristotelian teachers in the schools. Further, he comes to the
conclusion in the *Opus maius* that the greater philosophers in
the Greek, Islamic, and Christian traditions maintained that the Agent
Intellect *is* God, the source and agent of illumination. He
now makes this position his own, and attacks those teachers who hold
that the agent and the potential intellects are parts of the soul.



Bacon's short treatise on the soul in *CN* is titled
*Distinctio tertia de anima*. It provides an interesting window
on contemporary debates c. 1267-70 at Paris. It belongs with
Aquinas's masterful polemic, *De unitate intellectus contra
averroistas* and Siger of Brabant on Aristotle's *De
anima*.



He divides the work into seven chapters: (1) On the production of the
parts of the soul; (2) On the Sensitive Soul; (3) On the Unity and
Plurality of the Intellectual Soul; (4) On the Composition of the
Rational Soul; (5) On the Powers of the Soul: whether they are parts
of the soul; (6) On the Vegetative Soul; and (7) On the Parts of the
Intellectual Soul. 



The first chapter reviews the common teaching since 1250. Having noted
that before 1250, all philosophers and theologians held that the
vegetative and sensitive souls came to be by way of natural generation
and that the intellectual soul came from the outside, Bacon says,
"And still to this day (c. 1269-70) the English
theologians and all true lovers of wisdom (*philosophantes*)
uphold this position" ([OHI, IV], 282), that is, that the
intellectual soul alone is created by God while the vegetative and
sensitive souls in the human are produced from the potency of matter
in accordance with the laws of nature. He argues that those opposed to
this position rely on the Pseudo-Augustine, *De spiritu et
anima*, and on the *De ecclesiasticis dogmatibus* by
Gennadius. Those who follow these sources, he states, hold that
"the vegetative and sensitive souls are co-created with the
intellectual soul..." He describes this as a kind of
'folk-psychology'. For Bacon and "all
philosophers," embryology shows that the embryo is nourished and
grows prior to the infusion of the intellectual soul. Bacon states the
problem as follows:



> 
> 
> But if the vegetative and sensitive souls were co-created with the
> intellective soul, as *many moderns* teach publicly, then, they
> would not precede the intellective soul in being. And so these people
> are forced to claim that one needs a double vegetative and sensitive
> soul, one that is produced from the potency of matter through the
> power of nature; the other is created with the intellective
> soul...But no authorities hold this position, and experts in
> philosophy, therefore, dismiss it as nonsense. ([OHI, IV], 283) 
> 
> 
> 



Henry of Ghent among others advocated this doctrine of the co-creation
of souls.



In the second chapter, Bacon attacks some of the leading philosophers
at Paris: "But the leaders of the common philosophers at Paris
fall into other deadly errors, which the theologians contradict"
([OHI, IV], 284). For about ten years, the leader of the philosophers,
"an erroneous and famous man," held that "prior to
the existence of the rational soul, one must presuppose a specific
substantial difference educed from the potency of matter which places
man in the species of animal, such that the intellective soul does not
do so...This is contrary to the philosophy of Aristotle and to
all authors" ([OHI, IV], 284-85). A study of the
*Questiones* on *De anima* indicates the earlier Parisian
tradition out of which Bacon is working (Bernardini 2009; see also
Bernardini 2014). In the third chapter, Bacon makes explicit the
object of his polemic. It is the view commonly ascribed to Siger of
Brabant and the so-called Radical Aristotelians (Latin Averroists).
Bacon states:



> 
> We are concerned with this second proposition on the unity and
> plurality of the intellective soul. Therefore, they [the Latin
> Averroists] argue that the intellective soul (*anima
> intellectiva*) is one in number among all human beings. Therefore,
> they cover their error when they are compelled [to respond] stating
> that 'through philosophy it is not possible to hold anything
> else, nor is it possible to have any other position through *reason
> alone, but only through faith alone*.' ([OHI, IV],
> 286-87)
> 



This is the proposition that is analyzed and critiqued by Thomas
Aquinas in his *De unitate intellectus contra Averroistas*
(1269) [TUIA]. It is also closely related to the celebrated doctrine
of double truth imputed to the Latin Averroists by their Franciscan
opponents. Bacon's arguments, like those of Aquinas, deal
specifically with philosophical reasons for the mistaken positions of
the Averroists. The first two arguments are moral arguments: if there
were one identical intellect in all humans, the same person would be
both virtuous and vicious. The denial that 'this individual
human thinks' is contrary to both philosophy and faith. This is
contrary to the *Nicomachean Ethics* and would lead to a
destruction of moral philosophy.



The remaining arguments hold that the doctrine destroys "the
laws of nature," that is, of natural philosophy and psychology.
First, he presents Aristotle's arguments against the
transmigration of souls. Second, he argues that this intellect would
be infinitized and in power equal to God. Third, he addresses the
important issue of the connection between diverse imaginations and the
intellective soul. This could lead to the same person being learned
and ignorant at the same time in respect of the same things. Again,
injury to the sensory organs can lead to a person becoming insane. If
the sensory organs work, the existence of diverse imaginations will
not differentiate the intellect in different persons. Fourth, there
will be no unified object of knowledge. Bacon distinguishes between
the single object of the intellect and the "*intelligible
species*" by means of which we know that object:



> 
> 
> For when it will be argued that the *species* will be
> multiplied in diverse persons, I concede that the diverse
> representations of the same thing can be present to diverse persons
> because the thing itself produces its *species* according to
> every diameter, as was proved in *De multiplicatione
> specierum*. And so, just as in the diverse parts of the air the
> species of the same thing are diverse, and come to the eyes of
> different perceivers, so it is the case with the intellects of
> different persons. ([OHI, IV], 289)
> 
> 
> 



Thus, he makes a basic distinction between the thing which is the
object of knowledge and the representations (intelligible species) by
which one knows them. Fifth, Bacon holds that the Averroists leave no
room for new knowledge. Sixth, against the Averroist position that all
logicians and grammarians must have the one same knowledge, Bacon
holds that one must distinguish between the cognitive habit by which
the soul knows anything knowable and the object of knowledge in the
sense of "the object of knowledge," which is a unity.
Seventh, based on Aristotle's teaching on the *passiones
animae* (species/concepts), he holds that just as the soul is
multiplied, so too will knowledge be multiplied. And so in a real
sense, there is distinct and different knowledge in different human
beings.



Chapters four to seven on the parts of the soul place Bacon in the
context of the Franciscan and Dominican arguments on the parts of the
soul. These chapters show that Bacon was very active in the early
debates at Paris in which the unity of substantial form in Aquinas was
strongly criticized by the Franciscan School. Bacon is so critical of
Aquinas's position that he deems it heretical. He defends the
notion of plurality of forms while strongly arguing for the essential
substantial unity of the human being. Bacon also uses his remarks to
let the reader know that his study of *Perspectiva* was
undertaken to criticize the common teaching on natural philosophy
(including psychology) and medicine at the University of Paris.



This short treatise has the advantage of contextualizing Bacon's
works in the 1260s in terms of the debates on Latin Averroism. It
would appear that Bacon, like Bonaventure and Pecham, was an explicit
opponent of the young teachers of the Arts at Paris, especially Siger
of Brabant. Bacon and Pecham shared the same scientific concerns
(Hackett 2013a). And it would appear that Bacon's treatises such
as the *Perspectiva* were written with this context in mind.
Since, as we have noted above, Bacon provided a philosophical critique
of the issues concerning Latin Averroism already as a teacher at Paris
in the 1240s, we should see his intervention in the debates of
1266-72 as the criticism of an emeritus Professor of Philosophy,
now engaged with the theological arguments of the schools at
Paris.


## 5. Bacon's Later Philosophy: Language Study and Science in the Service of Both Moral Philosophy and Theology


### 5.1 Background



At the beginning of the *Opus maius* and related works, Bacon
offers a structural critique of scholastic practice in the
universities. He favors both language study and science over the
"Sentence-Method" as a way of interpreting the texts of
Philosophy and of Scripture. And he advocates training in mathematics
and the sciences as requirements for students in theology. Second,
Bacon's later works on language and science are written in the
specific historical and political context of the Mongol invasion of
Europe, the sack of Baghdad in 1258 by the Mongols, and the
geo-political situation of a Europe hemmed in by both the Mongols and
Islam. His sense of world geography was aided by the travel reports of
William of Rubruck [Southern, WVI]. The wider historical context for
Bacon's concerns has recently been outlined by Amanda Power
(Power 2013). The overall division of the *Opus maius* is
Platonic/Stoic: language study, natural philosophy/mathematics,
morals. The general context is theological and Franciscan: the arts
and sciences leading to human well being in this world and the next.
It is also clear that Bacon is constructing a "new model"
for medieval philosophy, one in which Aristotelian concerns are taken
up and transcended in a Neo-Platonism with significant Roman Stoic
influence and adapted to moral philosophy and Christian theology.
Metaphysics is taken up and completed in Moral Philosophy. The latter
becomes the end of linguistic and scientific study. Logic is reduced
to mathematics, and the applications of mathematics become central to
an understanding of the sciences (Perler 2005). The applications of
mathematics can in turn be used in religion and theology. Therefore,
in his later works, especially in the *Perspectiva* and
*Scientia experimentalis*, Bacon will define
*experientia-experimentum* in a distinctly new manner, one that
takes up and also goes beyond the use of this term in Aristotle. His
new definition advances on his own *Questiones* from the 1240s.
Peter King has recently claimed that Ockham was the first to create
this new definition of *experientia-experimentum* (2003). He is
correct that this definition is found in Ockham, but not in claiming
that this concept began with Ockham. The concept is formulated in the
scientific works of Roger Bacon and is found in a number of Franciscan
writers including John Pecham well before the age of Ockham (Hackett
2009).


### 5.2 *Opus maius*/Parts One and Two



Before presenting the seven parts of the *Opus maius*, it is
important to note a factor that is absent from the scholarship, that
is, how Bacon's Islamic sources structure this major work. These
sources, of course, are integrated with his Greek and Latin sources.
Most important here for the architecture of the latter work is the
*De scientiis* of Alfarabi. The division of the sciences and
the reduction of the linguistic and natural sciences to moral
philosophy is strongly influenced by this text. Part four and the
latter section of Part six on prognostication, and Part seven, IV, is
influenced by Abu Ma'shar's Introduction to Astronomy and
by his Book of Conjunctions. Part five on Perspectiva is a masterpiece
of synthesis of most of the major Greek and Muslim texts on Optics.
Especially important are the texts of Ptolemy, Alkindi, and Ibn
al-Haytham. This synthesis clearly influences Bacon's new
understanding of an experimental science. And yet in addition to this,
one must note that Ptolemy in his *Almagest*, Optics and
Astrology influences Bacon's understanding of method in the
sciences as it impacts the integration of reason and experience. And
in the third part of the Scientia experimentalis,Bacon is influenced
on the important commentary on Ptolemy'Astrology, namely, the
*Centiloquium* by Abu Ja'far IbnYusuf Ibn Ibrahim. But
since Bacon's *De multiplication specierum* is
acknowledged by him as the key to his Optics, one must note the
structural presence of the *De Radiis* attributed to Al-Kindi.
This work provides the basis for his doctrine of species that will be
spelled out for the geometry of vision in the Perspectiva. Since the
*Opus maius* and related later works are intended as sketch for
a grand linguistic, scientific, philosophical and theological work,
one must note the important openness that Bacon has for the science,
philosophy and theology received from the Muslim and Jewish worlds.
This is very different from the Anti-Arabism and the intermittent
Anti-Judaism that would become a central part of Western Renaissance
culture after 1300.



Part one examines "the causes of error" in education and
is critical of some theological limits on science. These causes are:
belief in unworthy authority; long custom; uncritical popular opinion;
concealment of academic ignorance in a display of rhetorical wisdom.
The polemic is presented as one of conflict among the canon lawyers
and theologians at Paris concerning the reception of Aristotle and
recent works on Greek and Arabic sciences, especially
astronomy/astrology. This is Roger Bacon's appeal to the Wisdom
of the Ancients



Part two contains the pre-Cartesian view of truth and wisdom as a
result of a universal revelation to the Hebrews that was transmitted
through the Greeks, Romans, and Islam to medieval Christianity. This
view would be influential in Philosophy up to the age of Francis Bacon
and Descartes. Roger Bacon links it to a doctrine of illumination
taken from Augustine, Avicenna, and the commentary on the
*Pseudo-Ptolemy: Centiloquium*. He contrasts the tradition of
the great philosophers such as Plato and Aristotle with the mythical
traditions from ancient times.


### 5.3 *Opus maius*/Part Three: On Language, *De signis* and *Compendium Studii philosophiae*



Part three deals with language study, grammar, semantics, and
semiotics, and contains Bacon's general theory of signs. The
1978 discovery by the late Jan Pinborg and his colleagues of *De
Signis*, a missing section of part three, led to intense study of
Bacon's semiotics and the philosophy of language in his later
works. Bacon's proposals are radical. 



Bacon's concerns with language in his later works transgress the
disciplinary boundaries of the medieval university. First, he demands
that the universities study the Wisdom languages, i.e., Hebrew, Greek,
Latin in one list, or Hebrew, Greek, Arabic, and Chaldean in another.
He wrote Greek and Hebrew grammars (GGHG). Bacon takes Latin as a
model for a natural language, the "mother language" of the
West. For Bacon, this language is dependent on Greek and Hebrew. He
distinguishes the "vulgar language" or "language of
the laity" from the "language of learning" of the
clergy. For him, vulgar language cannot be used in learning; it does
not have an adequate technical vocabulary. 



Bacon's relative originality consists in the fact that he brings
together the semantic and semiotic concerns of both Arts and Theology
or, as one might say, Aristotle and Augustine, into a creative
synthesis. From Augustine, he carries over significant elements of
Stoic Logic. From these concerns, he develops his own novel theory of
the sign. In the *Communia naturalium*, Bacon notes that he had
to develop a new logic needed to deal with his new interests in the
sciences. Indeed, Bacon uses the words *signification* and its
cognates in a manner quite different from the traditional
position.



The commonly used medieval definition of a sign was substitutional or
representational: "A sign is that which shows itself to the
senses and presents something else to the intellect." This
definition is similar to that of Augustine in *De dialectica*
(p. 86): "A sign is something which is itself sensed and which
indicates to the mind something beyond the sign itself."[3] In this case, the parts of our language are given by either God or the human so that the thoughts of the speaker can be communicated to the mind of the hearer. The expressions in language stand for the
thoughts of the speaker and represent them to the hearer. In *De
signis*, Bacon provides the following definition: "For the
sign is that which, offered to *the senses or to the
intellect*, represents itself to that intellect, since not every
sign is offered to the senses as the common definition of sign
supposes. However, on the testimony of Aristotle, another kind is
offered only to the intellect." He states that the *passiones
anime* (concepts/species) are signs of things, and such
*passiones* are habits of the soul and species
(representations/intentions) of the thing existing for the soul, and
therefore, "they are offered only to the intellect so that they
represent external things to that intellect" ([DS], 82). Some
interpreters claim that Bacon's definition of sign is close to
that of to that of Augustine in *De doctrina Christiana*:
"For a sign is something that apart from the impression it gives
to the senses, also causes something else from itself to be present to
the
 mind."[4]
 Augustine gives the examples of animal tracks leading us to think of
the animal, smoke leading us to think of fire, human expressions
leading to our understanding the mood of a person, and soldiers
answering the call of the trumpet in battle and then knowing where to
march.



One can see that Bacon in a manner uncommon for his times relates
Augustine's definition of sign to the inferential notion of sign
in the works of Aristotle. And so one can also see how Bacon,
influenced by Kilwardby and Fischacre, unites the different concerns
of the philosopher and the theologian.



Bacon continues and states: "The sign is in the predicament of
relation." This may sound innocent, but in Bacon's account
it has the effect of transforming the traditional relation between a
sign and its meaning, either a thing or a concept. The theologians
were aware of a twofold relation: that of sign to thing signified and
sign to the perceiver of the sign. For the majority of theologians,
the first relation is an essential and permanent relation; the latter
is accidental and non-permanent. Bacon reverses this. He remarks,



> 
> 
> The sign is in the predicament of relation and is spoken of
> essentially in reference to the one for whom it signifies. For it
> posits that thing in act when the sign itself is in act and in potency
> when the sign itself is in potency. But unless some were able to
> conceive by means of this sign, it would be void and vain. Indeed, it
> would not be a sign, but would have remained a sign only according to
> the substance of a sign. But it would not be a definition of the sign,
> just as the substance of the father remains when the son is dead, but
> the relation of paternity is lost. ([DS], 81)
> 
> 
> 



And so it is not sufficient that a sign have reference to what it
signifies (accusative) in order to be a sign; it is also required that
it have an interpreter (dative) for whom it signifies. In medieval
theology, the thing signified (accusative) has priority, and was true
even if there were no interpreters. The notion of this two-way
relation is found in Bonaventure, Rufus, and Fishacre among others,
and the thing signified holds ontological priority over the
relationship of sign to perceiver. 



For Bacon, the communicative relation to a hearer is basic, and the
relation to the thing signified is important but secondary in the
whole context of communication. The common theological teaching held
that the relation of sign to thing signified is primary and
fundamental. Once a name has been instituted, it does not change
(Maloney 1983b). And so, the name 'Caesar' can be used of
both the living and the dead Caesar. Against Rufus and Bonaventure,
Bacon held that this introduced ambiguity into language. Even in the
case of ordinary signs such as that of a tavern, they remain a sign
only potentially if there are no customers or staff.



Bacon's own classification of signs introduces distinctions that
reflect an integration of Augustine and Aristotle:



1.
Natural Signs
 
1.1
Signifying by concomitance, inference, and consequence
 
1.1.1 Necessarily
1.1.2 Probability

1.2
Signifying by configuration and likeness
1.3
Cause and effect

2.
Intentional Signs purposefully generated
 
2.1
Signifying conventionally by means of a concept
 
2.1.1
Linguistic signs by way of imperfect deliberation: *interjections*
2.1.2
Linguistic signs by way of perfect [completed] deliberation: *other parts of speech*
2.1.3
Non-linguistic signs (language of gestures, monk-signs, sign-boards)

2.2
Signifying naturally, *in the mode of affect*

2.2.1
Products of the sensitive soul: animal sounds
2.2.2
Products of the rational soul: *groans, exclamations, cries of
 pain*[5]




The distinction between 1 and 2 is taken from Augustine's *De
doctrina Christiana*. Bacon himself claims that he worked out the
typology himself prior to finding it in Augustine's great work
on interpretation. Modern scholars, however, believe that he must in
some way have borrowed it from Augustine (Maloney 1995). The
distinction between 2.1 and 2.2 is taken from the Aristotelian
tradition as handed down by Boethius. Type 1 signs occur naturally as
part of the agency of nature. Type 2 are signs only because they have
been willfully created as such by deliberation; included here are
linguistic and non-linguistic signs. However, Type 2.2 are designated
'natural' in a sense that is different from Type 1. These
sounds and groans are products of nature and happen instinctively but
in an "animate" action.



Interjections are a problem. They are parts of language, conventional
signs, and so conceptual, yet they are emitted suddenly and often due
to pain. They are similar in a way to the groans of animals (Type
2.2). This discussion is common to writers on grammar and logic from
the 1240s, especially in the works of Richard Kilwardby and similar
authors.



The signs in 1.1 on natural consequence indicate that Bacon has
integrated not only Aristotle and Augustine but also the work of
Averroes on the *Rhetoric* of Aristotle. Thomas S. Maloney has
argued that Aristotle's *De anima* plays an important role
in Bacon's distinction between signs by nature and signs by
intention (Maloney 1983a). Bacon provides an analysis of ambiguity and
equivocation in the *De signis* and *Compendium studii
theologiae* (Maloney 1984).


#### 5.2.1 Bacon and the Semiotic Triangle



In the traditional semiotic triangle inherited from Plato and
Aristotle, the sign is a symbol and symptom of the *passiones
animae* (concepts/species) in the soul and the latter in turn have
a relation of similitude to extra-mental things. And so the relation
of sign to thing is indirect. Bacon gets rid of the mediation of
concepts/species and has the sign refer directly to the object. In
this way, Bacon substitutes an extensional relation for an intensional
relation. Words can *directly* refer to individual things, be
they single objects in the world, mental objects, or philosophical
concepts. Primarily, then, words refer strictly to the present object.
Reference to past or future objects will require the extension of
univocal terms by means of analogy or metaphor. Simply because a sign
exists, it will not follow from that alone that the object of the sign
exists. As we saw above, without the interpreter of the sign, a sign
is a sign in name only or potentially. Bacon does not deny the
existence of the concept/species, but notes that a second imposition
of meaning is required to name it. As Umberto Eco puts it,
"Bacon definitely destroys the semiotic triangle that was
formulated since Plato, by which the relationship between words and
referents is mediated by the idea, or by the concept, or by the
definition" (Eco 1989, 61). The relation of sign to concept is
reduced to that of a symptom, which is no longer a symbol. Here one
can see the preparation of the ground for the semiotics of William of
Ockham and late medieval nominalism.


### 5.4 *Opus maius*/Parts Four, Five and Six: Mathematics and Philosophy of Nature (*De multiplicatione specierum*, *Perspectiva*, *Scientia Experimentalis)*



Parts four, five, and six of the *Opus maius* present the main
themes of Bacon's contribution to scientific education. It is
important to see his main contribution to science as one who advocated
"scientific education" in an Arts Faculty that was
predominantly dedicated to linguistic arts. Bacon had a very wide
reading knowledge of most of the newly translated work from Greek,
Jewish, and Islamic Philosophy and Science. His major claim to fame in
science is that he is the first Latin Western thinker to comprehend
and write on most of the ancient sources of optics. In brief, he
initiates the tradition of Optics/*Perspectiva* in the Latin
world. This tradition would be formulated as teaching text by his
contemporaries Pecham and Witelo. Bacon's optics was also read
and commented on in 14th century Italy by, especially by Lorenzo
Ghiberti. It was known to and used by Leonardo Da Vinci. And it was
part of the tradition of learning that led to Kepler and Descartes. In
his *Perspectiva* and *De scientia experimentali*, Bacon
outlines a sketch for a scientific method, one that takes optics as
the model for an experimental science. In fact, he succeeded in his
endeavor in that *Perspectiva* was added to the four
traditional university subjects of the *quadrivium*: arithmetic,
geometry, astronomy, music.



*Opus maius*, Part four, deals with mathematics and the
applications of mathematics. Bacon presents reasons for a reduction of
logic to mathematics (a kind of reversal of modern logicism) and sees
mathematics as the key to an understanding of nature (Perler 2005).
Clearly, he is proclaiming the "usefulness" of mathematics
for knowledge; he is not doing mathematical theory. And the branch of
mathematics that is important here is geometry. He applies it in
detail in the optical works edited by Lindberg. Following his
abbreviation of the *De multiplicatione specierum* in part four
of the Great Work, which shows how mathematics might be applied to
physics, he deals with the application of astronomy/astrology to human
affairs, the uses of mathematics in religious rites as in chronology,
music, symbolism, calendar reform, and geographical knowledge, and a
resume of astrology (Rutkin, 2019). It used to be thought that Bacon
was a Platonist in his view of the absolute priority of mathematics.
More recently, that view has been seriously qualified. He does not
reduce physics to mathematics. Indeed, his explicit work on
mathematics, the *Communia mathematica*, is not an exercise in
mathematics, but a presentation of the "common notions"
that are important for a variety of mathematical practices. Bacon
himself acknowledges those who were better mathematicians, namely,
John of London, Pierre de Maricourt, and Campanus of Novara (Molland
1997). In general, Bacon is more interested in how mathematics can
contribute to knowledge of the world as an aid to missionary activity.
He sent a map of the world to the Pope. 



Bacon was very interested in the applications of astronomy/astrology
to human events. Federici Vescovini (2011) has now provided the
essential context and linkage between medieval magic and philosophy,
enabling scholars to grasp the dimensions of fate and freedom as
understood by medieval philosophers and theologians. Although
committed to freedom of the will, Bacon held to a deterministic notion
of causation in nature based on the *Introductorium Maius in
Astronomiam* of the Islamic authority on Astrology, Abu Ma'
Shar (Albumassar), on the *De radiis* of al-Kindi, and on the
*Centiloquium* by Pseudo-Ptolemy (Ahmed Ibn Yusuf). And since
he held to a doctrine of universal radiation in nature, he had to
account for the influence of the heavens on the human body and hence
indirectly on the human mind. Much of the polemic in his later works
consists of a justification of this interest in an astrologically
necessitated universe in the face of traditional theological
objections. These works play a big role as background for his natural
philosophy in *De multiplicatione specierum*. He was also
interested in alchemy. It was his determined interest in some of these
areas of study that led to disagreement with his superiors in the
Franciscan Order, specifically, Bonaventure.


#### 5.4.1 The Philosophy of Nature



Bacon's treatise *De multiplicatione specierum*, his
major later work on physics, written before 1267, is closely related
to the study of light, vision, and perception in the
*Perspectiva*. David C. Lindberg (DMP, Introduction) has noted
that Bacon takes Grosseteste's physics of light, a development
of Al-Kindi's universal radiation of force, out of its
metaphysical background and develops a universal doctrine of physical
causation.



Lindberg had already traced the history of the emanation theory of
light from Plotinus to Bacon. Lindberg notes the influence of
al-Kindi's work on the rays of the stars but does not cited
detailed evidence. What Bacon achieves is a comprehensive theory of
physical force divorced from psychological, moral, and religious
interpretation. As Lindberg puts it (DMP, Introduction), in this work,
Bacon does not formally examine divine illumination of the intellect,
universal hylomorphism, the plurality of forms (properly qualified),
and the separability of soul. He restricts himself to presenting a
full theory of the physics of light. Species is the first effect of
any natural agent. As Lindberg puts it (DMP, Introduction),
"This is a complete physical and mathematical analysis of the
radiation of force--and, thus, of natural causation."



The use of 'species' in this account is not that of
Porphyry's logic or the perceptual notion of likeness. It
is"the force or power by which any object acts on its
surroundings." It denotes "al-Kindi's universal
force, radiating from everything in the world to produce
effects." As Bacon himself notes,



> 
> 
> species [force, power] is the first effect of an agent...the
> agent sends forth a species into the matter of the recipient, so that,
> through the species first produced, it can bring forth out of the
> potentiality of matter [of the recipient] the complete effect that it
> intends ([DMS], 6-7). This is a universal theory of natural
> causation as the background for his philosophy of vision and
> perception. Most importantly, species is a *univocal product of the
> agent*. The first immediate effect of any natural action is
> definite, specific, and uniform. This production is not the imparting
> or imposition of an external form. The effect of the species is to
> bring forth the form out of the *active potency of the recipient
> matter*. (DMS, 6-7)
> 
> 
> 

 Al-Kindi's *De radiis*, his optics, and
that of Ibn Al-Haytham form the background to this teaching on
species.


This also leads to an attempt to provide separate domains for material
and spiritual being. Bacon is adamant on this point: spiritual and
material being are entirely separate. Natural causation occurs
"naturally," according to regular processes or laws of
nature. There is no "spiritual being" in the material
medium as was commonly taught by other scholastic philosophers. That
is, Bacon objected to the use of the term 'spiritual being in
the medium'. No, for Bacon, universal causation is corporeal and
material, and matter itself is not just pure potentiality but is
rather something *positive in itself*. So, in terms of
explaining 'spiritual/intentional being' in the medium,
Bacon is of the view that the introduction of such terms muddy the
waters, especially if you are trying to come up with a comprehensive
doctrine of physical force. Hence, the general philosophy of nature
prepares the theoretical ground for the specific application of
mathematics to matters of vision and perception. It also allows for
and requires a metaphorical extension of these terms to moral and
religious domains.



Recent scholarship on Bacon's philosophy of nature, especially
that of Yael Raizman-Kedar (Raizman-Kedar, 2009; Raizman-Kedar,
dissertation, University of Haifa, 2009) places great emphasis on the
importance of the concept of *species* for Bacon's
account of perception and mind. She is correct to note that Bacon
places a kind of natural activity in the mind via species. This leads
in her view to natural species having a direct role in intellectual
activity as such. One could speak of the direct presence of material,
corporeal species in the intellect itself (see section 5.2 above for
Bacon's complex discussion of the role of signs in animal and
human knowing). Here, and also in the *Perspectiva*, we can see
the importance of the cogitative sense, as it takes on an
administrative role in animals analogous to reason in human beings.
But in this life, for Bacon, human beings cannot know things in the
world without the presence of species in the mind. Species as the
expression of universal agency act naturally in nature and in the mind
in a certain limited sense. Yet, Raizman-Kedar claims, "the very
same *species* issued by physical objects operate qua material
species within the intellect as well." She also claims that the
concept of divine illumination plays a secondary role in the
acquisition of knowledge, and that Bacon



> 
> 
> regarded innate knowledge as dispositional and confused, the
> *species*, representing their agents in essence, definition,
> and operation, arrive in the intellect without undergoing a complete
> abstraction from matter and retaining the character of agents acting
> naturally. In this way, Bacon sets the intellect as separate from the
> natural world *not in an essential way, but rather in degree*
> (my italics), thus supplying a theoretical justification for the
> ability to access and know nature. (Raizman-Kedar, 2009, 131; after
> 2012 the author writes as Kedar)
> 
> 
> 



Raizman-Kedar correctly stresses the central role of species
(material/corporeal) in the acquisition of intellectual knowledge of
material particular things in the world. Further, she carefully
distinguishes between the role of hearing and sight in the knowledge
process.



Hackett (2018c) raises questions about this conclusion. He points to a
significant problem with the translation of a central passage in
*Perspectiva* in support of this position. Further, by placing
Bacon alongside his confrere, one can see that the doctrine of
divine illumination plays a central role in both pure intellectual
knowledge, moral knowledge and knowledge of the natural world. Yes,
the material species are a necessary but not a sufficient element in
the acquisition of pure intellectual knowledge. Without the
illuminative process within from above, pure intellectual vision is
blocked. It is not at all clear that one can claim that Bacon is a
material monist. Bacon's separation of the account of physical
species in the DMP could lead one to think he has to be a material
monist, even with regard to species in the medium, sense, and reason.
And there is one sense in which this is true. But in the end, as he
states in both the DMP and the PRSP, matter and spirit are two
entirely separate kinds of substance. Hence, at a deep level, Bacon is
a substance dualist (medieval version).


#### 5.4.2 The *Perspectiva* and *De speculum comburentibus* (1266-67)



In his *Perspectiva* and related works, Bacon presents his
model for a careful and detailed application of mathematics to the
study of nature and mind. In imitation of the *De aspectibus*
of Alhacen (Ibn al-Haytham), he provided an application of geometry to
vision that within the terms of reference of his times was successful.
But he is critical of both Alhacen and Ptolemy. He sees himself as
answering some of the optical problems not solved by either
author.



Bacon's approach to vision and perception, however, is not an
exercise in modern mathematical optics. It should be seen as the
sketch of a physics of light as the basis for a philosophy of
perception and mind. The account of visual perception in terms of
natural philosophy, medicine, and philosophy of mind is found in Parts
one and a section of Part two. The account of *Perspectiva*
sets out a consideration of direct, reflected, and refracted rays, and
at the end of Part three concludes with the application of geometrical
models for moral and religious considerations. The analysis of natural
vision provides analogies and descriptions for an understanding of
divine influence.



Part one and also *distinctiones* one and two of Part two deal
with the structure of the eye, problems of vision, and visual errors.
The aim is psychological and epistemological, that is, Bacon sets out
the conditions for certifiable/verifiable and certain perception. The
theory of the eye is taken from the Galenic tradition handed down in
Constantine the African's translation of Hunyan Ibn Isaq and
from Avicenna and Alhacen. For this tradition, vision occurs when the
crystalline humor is altered by the intromission of visual species
from the object. Vision is completed when the species proceeds through
the vitreous humor to the optic nerve and through this to the common
nerve. It is here that a common visual judgment is made. Throughout
the text, Bacon makes reference to the kind of visual knowledge
possessed by animals, especially in the context of a discussion of the
cogitative sense. Bacon follows Ibn al-Haytham and imposes a
geometrical model on the eye, enabling him to give a geometrical
account of radiation through the eye. How then does one avoid
confusion in vision and gain verifiable clarity? For Bacon, the
perpendicular ray is primary; the other rays are treated as cases of
indirect vision, refracted in the rear surface of the crystalline
humor.



Bacon is next concerned with optical illusions, inverted images,
magnification, vision of distant objects, the moon illusion, and such
matters. He seeks in a rational and experimental manner to solve the
puzzles found in Ptolemy, Alhacen, and others. Still, he is a child of
his sources, which do not provide him with the more advanced data and
mathematical method that arose only later, in the seventeenth century.
But they do provide him with a functional qualitative geometry of the
eye and vision based on the best Greek and Islamic science. Bacon is
committed to an intromission theory of vision, though he combines it
with an extramissionist theory that avoids the anthropomorphisms of
earlier extramissionist theories. He uses the latter theory mainly to
emphasize the active role of the eye in vision.



In Parts two and three, he is to some extent successful in applying
geometry to problems of direct, reflected, and refracted vision. He
moved the study of these matters to a new level. The geometrical
arguments are worked out with careful diagrams and various appeals are
made to "experimental" conditions. What are these
conditions? Some of them are simple thought-experiments or even
reports of actual experiments from earlier writers. It seems clear,
however, that Bacon himself did experimental work with pinhole images,
lenses, and discrete observations. This does not lead to a pure
geometrization of nature, however, and he inevitably falls back on
physical, perceptual, and metaphysical arguments. One might argue that
he lacks the notion of infinity that is present in modern
geometry.



Bacon introduces another important item for science. He refers to the
"laws of reflection and refraction" as *leges communes
nature*. In his account of nature in *Communia naturalium*
and the later works in general, Bacon's view is that a general
law of nature governs universal force. This universal law of nature is
imposed on a world of Aristotelian natures. This notion would have a
significant future in experimental science.

 This concept of a
universal law of nature has been highlighted by M. Schramm (1998). It
has now been taken up by Yael Raizman-Kedar and Professor Giora Hon,
who are studying the development of universal laws of nature from
Roger Bacon to the Early Modern Period.


Bacon ends Part three with an account of how a better understanding of
natural phenomena could lead to a more accurate knowledge of the
natural phenomena mentioned in Scripture. He finds in visual phenomena
significant metaphors and analogies for use in moral and religious
teaching. A solution to David C. Lindberg's queries about
Bacon's attempt to combine elements of the intromissionist and
extramissionist theories of vision is addressed here. At one level, it
seems to be an akward combination of two conflicting theories of
vision. This combination can be understood when one notes that Bacon
is making use of the important issue of grace and free will issue as
the moral-religious background for his discussion of vision. In other
words, genuine theological concerns influence the manner in which
Bacon constructs his analysis of vision in the *Perspectiva*.
Thus, the analyses of Ptolemy and Alhacen had to be synthesized within
a definite theological framework.



Direct evidence of Bacon's influence here in making science
available for an educated public is seen in the use of his work by
Pierre de Limoges in his influential text, *De oculo morali*
(On the Moral Eye), written at Paris between 1275 and 1289. MS Paris,
BN Lat. 7434, owned by Pierre de Limoges, contains an early copy of
Bacon's *Perspectiva*. All of this suggests Pierre de
Limoges,*(magnus theologus et astronomus)* as a very early
reader of Bacon's works (Newhauser 2001). Both are genuinely
committed to theimprovement of the task of the preacher. Here, we see
the priority for Bacon of preaching over theology, or rather, the
latter is in service to the former (Johnson 2009).


#### 5.4.3 On the Nature of Experimental Science: *De scientia experimentali* (1266-67)



Presupposing the *Perspectiva*, in *De scientia
experimentali* and in related works on the halo and on burning
mirrors Bacon situates this new scientific practice as a desired area
of study in the medieval university. It is consequent on the study of
*Perspectiva*. Starting from Aristotle's account of
*empeiria* (experience), Bacon argues that logical argument
alone, even when it originates from experience, is not sufficient for
the "verification of things". Even arguments that have
their origins in experience will need to be verified by means of an
intuition of the things in the world. He distinguishes scientific
argument from moral and religious mystical intuition, although he does
allow for the notion of a revealed intuition in science. It is this
element that clearly separates Bacon's practice from that of
modern science. Just as in his concern with the certification of
language to gain individual reference, so too in science, Bacon
clearly wishes to have a way of certification for knowledge of the
individual.



His aim is to provide a *method for science*, one that is
analogous to the use of logic to test validity in arguments. This new
practical method consists of a combination of mathematics and detailed
experiential descriptions of discrete phenomena in nature. It would be
distinguished from the conjurations of magic and from moral and
religious belief. It would also be different from philosophy of nature
and from broad optical knowledge. These two areas are important for
experimental science, but they constitute general principles, so that
in themselves and without experiment, they do not provide access to
minute, detailed experiments. Nevertheless, for his description of the
first example of an experimental science, the study of the rainbow,
Bacon depends on the accounts handed on by Aristotle, Seneca, and
Avicenna. He is not uncritical of these accounts.



One source for Bacon's methodology in an experimental science
has been overlooked by the scholarship. It is clear to all that Bacon
made much use of and privileged Ptolemy's Optics. What has been
missed is that Bacon was also influenced by Ptolemy's
methodology in the introductory chapter to the *Almagest*. The
combination there of experience and geometrical reason is in some
respects different and more detailed than in Aristotle's
scientific methodology. And so even as Bacon uses Aristotle's
texts, he is employing the methodological assumptions of Ptolemy. 



Further, Bacon's very close connection of experience and reason
is influenced by his concerns with medical matters. (Roger Bacon,
*De erroribus medicorum*). This text provides a wider
discussion of Chapter one of *Opus maius*, Part six. 



The context for Bacon's writing on topics from the
*Meteorology* of Aristotle came from the presence in Paris of
the new translation of this work from Greek into Latin. With the
recent critical edition of the *Aristoteles Latinus* version of
the *Meteorology*, it is clear that Bacon is deliberately
offering a criticism of William of Moerbeke's translation. Bacon
contends that the translations are not adequate and that the
translator did not know the required sciences, especially
*Perspectiva*, proposing instead a more accurate mathematical
analysis of the phenomenon of the rainbow.



Bacon's own important contribution is to be found in his
calculation of the measured value of 42 degrees for the maximum
elevation of the rainbow. This was probably done with an astrolabe,
and in this, Bacon advocates the skillful mathematical use of
instruments for an experimental science. That Bacon had mathematical
competence in this field can be seen in his account of the halo in the
*Opus tertiium* (OQHI) and in his complex arguments in *De
speculis comburentibus*. Bacon takes up Grosseteste's theory
of refraction and tries to work out the difficulties in the latter. It
would appear at first glance that Bacon is rejecting the notion of
refraction out of hand (Lindberg 1966), but in fact he is only
demonstrating that refraction as formulated by Grosseteste did not
make experimental or rational sense. Bacon knew the rules governing
the geometry of refraction. Important here is his emphasis on the role
of individual drops of water for the process of reflection and
refraction. The new research on the *De iride* of Grosseteste
by Cecilia Panti and the other editors of the Oxford/Durham Robert
Grosseteste project will shed much light on these matters. A correct
account of the rainbow would be summarized some forty years after
Bacon in the *De iride* of Theodoric of Freiberg (d. c. 1307)
[TFT], with his account of a single reflection and double refraction
in single drops of water. 



A second task for experimental science is the discovery by
'experience' alone of instruments (e.g., the armillary
sphere), new medical cures, chemical discovery, and military
technologies. An important item here is the discovery of magnetism. It
would seem that Bacon is reporting on the actual experimental work of
Magister Petrus Peregrinus (fl. 1260-77), author of *De
magnete*, who is lauded in the *Opus tertium* as the only
worthwhile "experimentalist" at Paris (see Silvia Nagel
2012). Bacon has been lauded down the centuries for his medical
learning, but recent scholarship has limited the number of works
attributed to Bacon. Still, it is important to note that he did draw
on medical practice to set out rules and procedures. Here, the recent
research of Agostino Paravicini-Bagliani (1991, 2000) shows that Bacon
shared these interests with other outstanding scholars such as Peter
of Spain (Pope John XXI). The very concept of the 'prolongation
of life' so forcefully proposed by Bacon in his later works
found very receptive readers at the Papal Curia in Viterbo. The Papal
Curia had by 1266 become a center for medical and scientific study.
The third task is that of the prognostication of the future on the
basis of astronomical/astrological knowledge. This section, depending
on Pseudo-Ptolemy, *Centiloquiium* and Abu Ma'shar notes
that this revelatory divination is earier and more available than the
more complex regular astronomy that requires constant observation and
the skillful uses of Tables and Instruments. These are not always
readily available. 



The conclusion to the *De scientia experimentali* is important.
Bacon presents the ideal of the "philosophical
chancellor"who will organize science and its technological
products for the benefit of *Res publica Christiana*. In this,
he is influenced by the important "Mirror of Princes" from
the Islamic World, the *Sirr-al-'asrar (Secretum
secretorum)* (OHI, V). Stewart C. Easton (1952) proposed that this
work was the guiding vision for Bacon's reform of science.
Williams (1994) has argued that Bacon completed the edition of this
work after his return to Oxford ca. 1280 or a few years before that
date. Still, there is much cross reference between this work and
Bacon's writings in Paris ca. 1266-71.



David C. Lindberg (1997) has given a succinct summary of Bacon's
model for an experimental science [RBS]. He sees four main aspects.
First, Bacon's perspectival theories were not his own creation.
He took the best available materials from Greek and Islamic scholars
and produced his own synthesis. Second, there is much evidence that
Bacon himself did mathematical work and experiments with visual
phenomena such as pinhole images and measurement of the visual field.
Third, as seen above, Bacon correctly calculated the maximum degree of
elevation for the rainbow. Fourth, the experiments in Bacon,
especially in the *Perspectiva* served "theoretically
significant functions" by supplying observational data that
required explanation in terms of a given optical theory. The usual
role of experiment in Bacon is to "confirm, refute, or challenge
theoretical claims."



One might have expected Bacon to have given equal treatment to
astronomy, but in this field he was a child of his time. He reports on
the accounts of Aristotle, Ptolemy, and Alfraganus (OHI, IV). He
discusses the pros and cons in scholastic, but does not advance the
field as he did for *Perspectiva*. 


### 5.5 *Opus maius*/Part Seven: *Moralis philosophia*



Bacon's *Moralis philosophia* (= *Opus maius*, VII
= RBMP) comprises the philosophy of religion, social philosophy, a
theory of the virtues, an astrological-sociology of religion and
cultures, and an account of argument and rhetoric.



Bacon describes the object of moral inquiry as follows: "This
science is preeminently active, that is, operative, and deals with our
actions in this life and the other life" ([RBMP], 3). It is
focused on human action. Of course, many human actions deal with
issues that are the concern of the natural and linguistic sciences.
Bacon notes that these sciences are active and operative but concerned
"...with artificial and natural works which refer to the
speculative intellect, and they are not concerned with those things
*which refer to the practical intellect, which is called practical
because it exercises operations of good and evil*" ([RBMP],
3). These works of the human being (*operabilia)* are
"...more difficult to know than the objects of speculative
knowledge." These include "...the highest truths
concerning God and divine worship, eternal life, the laws of Justice,
the glory of peace, and the sublimity of the virtues" ([RBMP],
247). For Bacon, the human ability to deal with these topics is
affected by a certain corruption of the human will. 



Moral science has two parts. The first is speculative, dealing with
ultimate moral truths. The second deals with the process of moral
persuasion: "The practical part is related to the first part as
the curing of the sick and the conserving of health, which are treated
in practical medicine, are related to that part of medicine which
teaches what health is..." ([RBMP], 248).



Part one deals with the object and method of morals science and with
an outline of a philosophical anthropology based on Platonic,
Aristotelian, and Stoic texts in which Bacon argues for an Augustinian
view of the place of human beings in the world. This includes a
section on metaphysical proof for God's existence. And the
ancient source texts are treated as testifying to the universal
religion of Christianity. Part two is a very brief outline of the
structure of social life, taken from Avicenna.



Part three, the most substantial in the book, is concerned with virtue
and vice. Bacon's own text for this part of the *Opus
maius* still exists and one can see his personal editorial remarks
in the margins. He did not have time to write a formal treatise, and
so he presents an anthology of texts from Seneca and excerpts from
Cicero with comment. This is preceded by a brief resume of Aristotle
on the virtues. But it is clear that Bacon favors the image of the
Stoic wise person as his model for virtue. Bacon places great emphasis
on magnanimity as a virtue for the Prince and Prelate. Magnanimity of
the greatest of the natural virtues. And it must not be confused with
Christian humility. This distances Bacon from Bernard of Clairvaux and
Bonaventure. For Bacon, Christian humility has its own distinctive
role reflecting the relation of the human to the cosmos and to God.
Above all, Bacon is concerned with reproducing as much of the
Aristotelian and Stoic accounts of virtues as possible, and he is
concerned with making the *Dialogues* of Seneca known to Pope
Clement IV. In particular, he is most of all concerned with
Seneca's *De ira*, which he regards as a fundamental text
for the moral instruction of princes and prelates. Certainly, Bacon,
as he does in the *Secretum secretorum*, presents himself as a
moral advisor to Princes. 



Part four provides an astrological sociology of human nations or
"sects", relying on the moral/political account of
al-Farabi and on the astrological views of Abu Ma'shar
(Albumassar). Bacon had a wide knowledge of the world including the
customs of the Mongols, and so he compares Mongol, Jewish, Arab, and
Pagan civilizations.



Part five deals with the role of rhetoric in moral persuasion. Bacon
is convinced that rhetoric is closely connected with logic, and
believed that the university system failed by teaching only grammar
and logic (linguistics). The omission from the university curriculum
of rhetoric and poetics, as found in Aristotle and as interpreted by
al-Farabi and Averroes, was in Bacon's view a mistake. He knows
the latest translations and remarks:



> 
> 
> But al-Farabi has presented to us the meaning of this kind of
> argument, and Avicenna, al-Ghazali, and Averroes have done likewise.
> Because of this, one ought to present an account of the nature of
> poetic argument, and it falls to *logic* alone to compose such
> a book, since the composition of argumentation pertains to
> *logic* alone...The appropriate presentation of this
> argument is found in [my] *Moralis philosophia*, and in its
> use, and likewise in theological proofs and doctrines; and in such
> moral matters, this kind of argument moves a [person] much more than
> does a demonstrative argument since it has much greater power. And I
> have already composed a treatise on this [rhetorical-poetic] argument
> in my works on *logic*, and I have shown there what is proper
> to this science. ([OHI, XVI], 16-17)
> 
> 
> 



He continues and notes that according to Aristotle and al-Farabi, this
argument makes use of appropriate language so that the self can be led
to virtue and to overcome of vice. He then links up the Greek and
Islamic sources with the regular sources in the Latin tradition such
as Cicero, Seneca, and Augustine. And he distinguishes carefully
between demonstrative, dialectical, and rhetorical forms of
argument.


### 5.6 Bacon's Political Philosophy: the *Secretum secretorum*



Bacon devoted considerable time to the study of this work, the Latin
translation of the Arabic work on statecraft in the tradition of
Mirrors for Princes entitled *Sirr-al-'asrar*. He worked on
the text at Paris and completed the edition of this text with
introduction and notes at Oxford after his return there from Paris c.
1280. This is the most important text on government and the education
of the Prince prior to the writing of *The Prince* by
Machiavelli. The work is divided into four parts. Part one begins with
the letter of Alexander to Aristotle and deals with the king's
maintenance of the kingdom. It deals with virtues, largesse, and
gifts. It is an account of the behavior expected of a King. Part two
deals with health care, medicine, and the origins of the sciences.
Part three deals with alchemy and with the human emotional structure.
Part four deals with physiognomy and anthropology. Bacon's
introduction is substantial, consisting of seven chapters. It is
closely connected with his account of astrology in *Opus maius*,
part four, and with *scientia experimentalis* in part six. His
sources are mostly Islamic and include the *De radiis* and *De
aspectibus* of al-Kindi and the introduction to astrology of Abu
Ma'shar. Bacon proposes a kind of statistical predictive
astrology, and so has to deal explicitly with the issue of freedom and
determinism. He objects to a kind of infallibilist necessitarianism
and thinks that provided "possibility" and
"contingency" can be guarded, one can predict what can
happen in nature and in human society (due to the effects of the
elements on temperament) in a general manner. Thus, the ruler will
have need of the astrologer who will function as a kind of doctor,
psychologist, sociologist, and political theorist. This is a far cry
from a contemplative ethics. It is significant that in the work
entitled *Errores philosophorum* ascribed to Giles of Rome, a
contemporary of Bacon at Paris, many of Bacon's sources are
severely criticized. In the *De regimine principium* (1280s),
Giles, unlike Bacon, provides a moral education for the prince that is
entirely based on Greek and Latin sources, especially on
Aristotle.



The idea of secrecy and secret books associated with Roger Bacon
continued into the Renaissance (Kavey 2007), with the depiction of
Roger Bacon on stage in a drama by Robert Greene.


## 6. Conclusion



It will be clear from this account that Roger Bacon was an important
teacher of the Arts at Paris in the 1240s. He was ahead of his time in
the vigorous manner in which he integrated the new Aristotle with the
traditional Latin traditions of grammar and logic. He taught for a
long period in the Arts. He later called himself an expert in the
philosophy of Aristotle as interpreted by Avicenna and Averroes. And
we should also add Avicebron (Solomon Ibn Gabirol). By 1248-49 he
seems to have become an independent scholar. He then, it would seem,
returned to England, where, under the influence of Adam Marsh, friend
of Robert Grosseteste, Bishop of Lincoln, he was attracted to
interests associated with both scholars: language study including the
learning of ancient languages, experimental concerns such as optics
and experimental science, and a renewed critical study of the text of
Scripture. When Bacon returned to Paris in the 1250s, he was to oppose
what had become a profound change in the methodology of university
learning, that is, the introduction of the
"Sentence-Method" into the study of theology. For Bacon,
this was a destruction of practices that he associated with Robert
Grosseteste. Taking up the flag of the Bishop of Lincoln (d. 1253), he
became the great critic of the Parisian mode of doing philosophy and
theology. As we saw above, Bacon was already by 1266 very concerned
with the new heterodox interpretations of Aristotle found in the
Faculty of Arts. His later works for Pope Clement IV must be read in
the context of the Parisian debates on Latin Averroism
(1266-1277).



The later Roger Bacon has a good knowledge of the geography and
history of the world and an awareness of geo-politics. In this
context, he devoted much time to the important work on the education
of the Prince, the *Secretum secretorum*. He may have returned to
Oxford c. 1280, if not before. There, he completed his edition, with
notes and introduction, of this work. In his last work, the
*Compendium studii theologiae* (c. 1292), he repeats some of the
main arguments from the 1260s against Richard Rufus of Cornwall. Roger
Bacon sets out themes in his philosophy of language, philosophy of
nature, and moral philosophy and theology that would influence
fourteenth century writers such as Duns Scotus and William of Ockham,
among others. Jeremiah Hackett examines the influence of Roger Bacon
on the philosophy of mind in John Pecham (Hackett 2018c).
Bacon's influence on the fourteenth century has been documented
by Katherine H. Tachau (1988). He is much more important for the
philosophy of the thirteenth and fourteenth centuries than has
hitherto been recognized. The editors of Peter of John Olivi on matter
have noted the appropriation by Olivi of Bacon's teaching on
matter. Doninique Demange and Yael Kedar have demonstrated Peter John
Olivi's critical appropriation of Bacon's theory of Vision
and his natural philosophy (Demange & Kedar, 2020). Jeremiah
Hackett (2018a) has suggested that in the early to mid-1260s, Olivi
may have been the Iuvenis Johannes, Bacon's star student.
Recently, Mattia Montovani has written a very important study on the
importance of Bacon's theory of vision for the new Cartesian
discussions of vision in the early 17th century. It is a study of
major significance for the influence of Bacon on early modern
philosophy. (Montovani 2020) As noted above, the newly formed
*Roger Bacon Research Society* will in the near future do much
to further the study of the scientific, philosophical and theological
works of Roger Bacon.