## 1. Introduction




Philoponus' oeuvre comprises at least 40 treatises on diverse
subjects such as grammar, logic, mathematics, physics, psychology,
cosmology, astronomy, theology and church politics; even medical
treatises have been attributed to him. A substantial part of his work
has come down to us, but some parts of it are known only indirectly
through quotations or translations into Syriac or Arabic. Although
his fame rests predominantly on the fact that, even within some of his
commentaries on works of Aristotle, he initiated and in fact
anticipated the eventual liberation of natural philosophy from the
straitjacket of Aristotelianism, his non-polemical commentaries on
Aristotle as well as his theological treatises have recently become more widely studied, translated, and appreciated.



 Philoponus' intellectual career began when he was a pupil of the
Neoplatonic philosopher Ammonius, son of Hermias, who had been trained
by Proclus at Athens and was head of the school at Alexandria. Some of
Philoponus' commentaries profess to be based on Ammonius' lectures, but
others give more room to Philoponus' own ideas. Eventually, he
transformed the usual format of commentary sympathetic to Aristotle's views into a discourse
of open criticism. In the course of this critique, Philoponus examines and repudiates
fundamental Aristotelian-Neoplatonic tenets, most prominently the
doctrine of the eternity of the world. His style of philosophical commentary, doggedly
disrespectful of authority, as well as the
conclusions he drew, antagonized Philoponus' pagan colleagues.
Their fierce enmity may have compelled him to abandon his philosophical
career in the 530s; Philoponus never succeeded his teacher
Ammonius as head of the school. Apparently he altogether abandoned his philosophical career. In the second half of his life he devoted his considerable energy
to the theological debates of his time. Ironically, the
orthodox church condemned him posthumously as a heretic (in 680-81)
because of his tritheistic interpretation of the trinitarian dogma.
Understanding the contested concepts within this debate (i.e. those of person, nature,
substance, and hupostasis) in strictly Aristotelian senses, Philoponus was
perceived to be enunciating not a single god in three persons (Father, Son,
and Spirit), but actually three separate divinities.



 Reading Philoponus as well as the writings of his tireless adversary
Simplicius, one gets the impression that, in the 6th century CE, traditional
pagan learning had become desperately insular. The intense
incompatibilities between Greek philosophy and Christian dogma are
readily visible on every level of Philoponus' work
as he struggles to hold his faith accountable to reason. Although his
mode of thinking betrays a strong Aristotelian influence, it also
displays a certain doctrinal affinity to Plato stripped of the
accretions of layers of Neoplatonic interpretation. The style of
Philoponus' writing is often circuitous and rarely entertaining,
displaying at times an almost pedantic rigor of argument and
exposition. Yet he complements this kind of discourse with a remarkable freedom of
spirit that allows him to cast off the fetters of authority
as a criterion of truth, be it philosophical or
theological. Philoponus' works were translated into Arabic, Latin
and Syriac, and he influenced later thinkers such as Bonaventure,
Gersonides, Buridan, Oresme and Galileo.


## 2. Extant Philosophical Commentaries




The early extant work of "John the Grammarian," on ambiguous words in Greek
distinguishable only by their accent, is philosophically
insignificant. So I leave these aside, and pass on to give an overview in this section of his extant
philosophical writings, first and foremost his commentaries on
Aristotle. In order to appreciate the magnitude of Philoponus'
achievement as philosopher and scientist, one has to take into
account, at least partially, the intellectual culture in which he was
brought up. A common way that philosophers in late antiquity developed
and propagated their own ideas was by composing commentaries on the
classical philosophical texts of Plato and Aristotle. Generations of
such commentaries were written from the time when Aristotle's works
became again accessible to a wider audience in the first century
BCE down to the seventh century CE and beyond, forming a rich and largely coherent
tradition. The majority of ancient commentaries still extant today
were written by Neoplatonists as textbooks for their philosophical
courses. Typically, these works have a number of features in common:


1. The commentaries consisted in an extremely detailed oral exegesis
of a philosophical text, designed for the benefit of students.
2. Not uncommonly, selected pupils were responsible for taking
verbatim notes of their teachers' exegeses, thus turning the
lecture into a book roll.
3. Each set of lectures and resulting commentary constituted a step
within a substantial curriculum of philosophical training which began
with Aristotle and aimed at progressing towards Plato.
4. A commentator was expected to demonstrate the agreement between
Plato and Aristotle, indeed, to show forth the harmony among all
"ancient" philosophers (i.e., those down to the time of
Aristotle) including Homer.
5. Finally, doing philosophy in this way was not only an education,
it was also and even more so a pagan religious exercise, empowering
thinkers to perfect their intellect and their character with a
view to becoming godlike as far as is humanly possible.



 After a basic education in "grammar" as well as studies in
classical Greek language and literature, John Philoponus, who was
probably born into a Christian family, embarked on this curriculum
(ca. 510). As a pupil of Ammonius (ca. 440-520) he assumed
responsibility for writing down the lectures of the school's by then
ailing head: Philoponus' commentaries on Aristotle's *On Generation
and Corruption*, *On the Soul*, *Prior Analytics*
and *Posterior Analytics* explicitly state in their titles that
they are based on Ammonius' seminars (*ek ton
synousion Ammoniou*). The commentaries on the
*Categories*, *Physics* and *Meteorology* do not
make such claims, which suggests, in conjunction with other evidence,
that Philoponus was by that time teaching these courses on his own. He presumably
took over as lecturer from Ammonius at some point, although he never
held the chair of philosophy but remained in the status of a
'*grammatikos*', i.e. a professor of philology.
After the death of Ammonius the school's leadership seems to have
passed into the hands of the mathematician Eutocius and then on to the
philosopher Olympiodorus (ca. 495-570), who remained a pagan and, remarkably, still
taught in then-Christian Alexandria unperturbed as late as 565.



 In many ways, Philoponus' commentary on the *Categories*
may be regarded as typical of its kind. The exegesis of
Aristotle's text is prefaced by a general clarification of
matters of interest for the student who reads philosophy for the first
time. (Similar preliminaries can also be found as prefaces to
commentaries on Porphyry's *Introduction*.) Aristotle's
logical works were arranged in an order of increasing complexity,
beginning with the *Categories*, which deals with simple,
uncombined utterances. This was followed by *De
interpretatione* (on propositions), *Prior Analytics* (on
syllogism) and *Posterior Analytics* (on proof). Discussing the
problem of the subject matter (*skopos*) of the
*Categories*, Philoponus says - roughly in agreement with
Iamblichus - that the *Categories* are about simple utterances
(*phonai*) signifying simple things
(*pragmata*) by means of simple concepts
(*noemata*; *In Cat.* 10).



 Most Neoplatonists followed Alexander of Aphrodisias in regarding
logic not as a separate philosophical discipline (that was the Stoic view) but
rather as philosophy's tool, its *organon*. In their
commentaries on the *Prior Analytics*, both Philoponus and
Ammonius side with that tradition and reject the Stoic view, but they
add that in the case of Plato, dialectic may well be regarded as part
of Platonic philosophy (witness dialogues such as *Phaedrus*
and *Phaedo*) but also as an exercise in its own right serving
as philosophical tool (witness the *Parmenides*;
cf. Philoponus, *In An.Pr.* 6-9). The contemporary Athenian
Neoplatonist Simplicius, who spent much acumen on repudiating and
excoriating Philoponian cosmological ideas, denied altogether Philoponus'
competence as a logician, and modern scholars tend to agree with
him. Historians of logic, however, acknowledge that Philoponus was the
first to render a satisfactory account of the syllogism (subsequently
the traditional one), stating that the major premise includes the
predicate term of the conclusion, the minor premise the subject term
(*In An.Pr*. 67). In Philoponus, too, one encounters for the
first time a particular diagram that schematised what kind of
conclusions (i.e. universal affirmative, universal negative,
particular affirmative, or particular negative) follow from what kind
of premises. This diagram, later to be called by the schoolmen
'asses' bridge' (*pons asinorum*), enabled students
of logic more easily to construct valid syllogisms (*In
An.Pr*. 274).


### 2.1 Theory of Light




The commentary on Aristotle's *On the Soul* is apparently the
earliest to contain passages in which Philoponus at times abandons
conventional exegesis in order to criticize an Aristotelian doctrine, a
tendency which becomes more and more conspicuous in the *Physics*
commentary, dated to 517. Scholars now believe that at least some of
these deviations from commentary proper derive from later revisions
of earlier expositions in the classroom. One can distinguish between two kinds of
criticism: substantive modification of Aristotelian ideas on the one
hand, and outright rejection on the other. Philoponus' commentary
*On the Soul* presents a good example of the former kind of
criticism. In *On the Soul* II 7 Aristotle takes light to be
incorporeal, and he describes its appearance as an instantaneous
transition from the potentiality (*dunamis*) of a medium
to be transparent to the actuality
(*energeia*) of transparency. At pp. 330ff of
his commentary, Philoponus offers a constructive kind of criticism
that seems to have had momentous consequences for his eventual
conceptualization of the theory of the impetus (see below). Philoponus
contends that Aristotle's view fails to account both for the laws
of optics and for the plain phenomenon that the region below the moon
is warmed by the light of the sun, a celestial body. In an
Aristotelian spirit of modifying the theory so as to save the
phenomena, he proceeds to re-interpret the term
*energeia* not as a state of actuality, but rather as an
'incorporeal activity' which, besides constituting the
transparency of the medium, is also capable of warming bodies. Philoponus argues that in the same way soul, as an incorporeal activity in the
body, causes the animal to be warm. Due to this novel interpretation
of Aristotle's terminology, light is now understood not
statically but as something dynamic. And it is possible to trace
Philoponus' further development of the idea. In the
*Meteorology* commentary, which belongs to a stage when
Philoponus had already abandoned the Aristotelian assumption of an immutable
celestial fifth element (ether), he argues that light and heat may be explained best as consequences of the nature of the sun, which is
fire (*In Meteor.* 49). Heat, so he explains, is generated when the rays
emanating from the sun are refracted and warm the air through
friction.


### 2.2 Theory of Impetus




The *Physics* commentary contains an array of examples of
innovative and damagingly critical commentary. One of the most
celebrated achievements is the theory of impetus, which is commonly
regarded as a decisive step away from an Aristotelian dynamics towards
a modern theory based on the notion of inertia. Concepts akin to those
deployed in Philoponus' impetus theory appear in earlier writers
such as Hipparchus (2nd c. BCE) and Synesius (4th c. CE), but
Philoponus nowhere intimates that he was influenced by any one of
them. As far as one can tell from the text *In Phys.* 639-42,
he takes his point of departure from an unsatisfactory Aristotelian
answer to a problem that was to puzzle scientists for centuries: Why
does an arrow continue to fly after it has left the bow-string, or a
stone after it has ceased to be in contact with the hand that throws
it? Since Aristotle supposed that a) whenever there is motion there
must be something which imparts the motion, and b) mover and moved
must be in contact, he was led to conclude that the air displaced in
front of the projectile somehow rushes round it and pushes from
behind, thus propelling the projectile along. To be sure, the rapid motion of an object through a medium creates turbulence, but this turbulence does not sustain any movement but contributes to its deceleration. Aristotle's theory was still in
vogue among Peripatetic scholars of the sixteenth century, despite the fact
that a thousand years earlier Philoponus had thoroughly dismantled it. He
proposed instead, much more plausibly but still erroneously, that a
projectile moves on account of a kinetic force which is impressed on
it by the mover and which exhausts itself in the course of the
movement. Philoponus compares this impetus or 'incorporeal
motive *energeia*', as he calls it, to the activity earlier attributed to light.



 Once projectile motion was understood in terms of an impetus in this
way, it became possible for Philoponus to reassess the role of
the medium: far from being responsible for the continuation of a
projectile's motion it is in fact an impediment to it (*In
Phys.* 681). On this basis Philoponus concludes, against
Aristotle, that there is in fact nothing to prevent one from imagining
motion taking place through a void. As regards the natural motion of
bodies falling through a medium, it was Aristotle's contention that the
speed is proportional to the weight of the moving bodies and
indirectly proportional to the density of the medium. Philoponus repudiates this view by appeal to the same kind of experiment that Galileo
was to carry out centuries later (*In Phys.* 682-84).


### 2.3 Space and Place




Philoponus' impetus theory ties in with other far-reaching
criticisms of Aristotelian principles of physics. Aristotle had
dismissed the notion of a void as a logical
impossibility. Philoponus concedes that in nature empty spaces never
become actual, but he insists that a clear conception of the void is
not only coherent but also necessary if one wants to explain movement
in a plenum. When bodies move and in consequence exchange places, this
presupposes that somehow there is empty space available to be filled
by them (*In Phys.* 693f.). Again, there are certain phenomena
which clearly exhibit the force of the vacuum, for example handling a
pipette (*clepsudra*), which allows one to raise small
quantities of fluids, or the fact that one can suck up water through a
pipe (*In Phys.* 571f). Philoponus' elaborate defense of
the void (*In Phys.* 675-94) is closely related to his
conceptions of place and space (*In Phys.* 557-85). Aristotle
defined the place of a body as the inner surface of the body or all
the bodies taken together that contain it (*Phys.* IV 4);
Philoponus replies that place ought instead to be conceived as the
three-dimensional extension identical to the determinate size of the given
body, i.e. its volume. This was also the theory of the Stoic
Chrysippus, but there is no indication in the extant text of
Philoponus (as there are in his later works) that he saw himself
influenced here by the Stoics.


### 2.4 Theory of Matter




Like place, space as a whole is the indeterminate three-dimensional extension everywhere devoid
of body, though it is not actually infinite - so much Philoponus
concedes to Aristotle. Philoponus' discussion of matter builds
upon this conception of space. In the *Physics* commentary
(687f.) he argues in a similar vein to Aristotle in
*Metaphysics* VII 3: In abstracting all qualities and other
determinations from body Aristotle arrived at a conception of
characterless, undetermined matter, an idea of matter like the "prime matter" that
the Neoplatonists later defined as formless and incorporeal (because
it was no actual body, but only the necessary underlying condition
*for* bodies). Philoponus, in contrast, arrives at something
he calls corporeal extension (*somatikon
diastema*), which is a composite of Stoic-Neoplatonic prime
matter and indeterminate quantity and must not be confused with
Philoponian space. His argument here may still be regarded as an
elaboration on or correction of Aristotle. However, in Book XI of the
polemical treatise against Proclus (see below, 3.1) he jettisons the
Neoplatonic conception of prime matter and posits as the
most fundamental level of his ontology 'the
three-dimensional', as he calls it, i.e. indeterminately extended
mass. In this he claims to be following the Stoics (*Aet.*
414), and it has been pointed out that this ontological level is
reminiscent to us of the Cartesian *res extensa*, although
Descartes would not allow Philoponus' distinction between space
and corporeal extension. In order to rebuff the likely objection that
'the three-dimensional' cannot be the most fundamental level of being
because extension, belonging to the Aristotelian category of quantity,
is an accident and requires the assumption of a distinct underlying
subject, Philoponus argues that extension is in fact not an accident,
but an essential and inseparable differentia of 'the
three-dimensional', just like heat in fire or whiteness in
snow. Thus quantity (corporeal extension) is constitutive of body as
such. This amounts to a promotion of one sort of quantity to the
category of substance. There are indications that Philoponus would
accordingly have modified Aristotle's scheme of the
*Categories* if he had revised his early commentary on that
treatise.



 The incomplete commentary on the *Meteorology* may well be the
last commentary Philoponus wrote on Aristotle. It is instructive to
notice how the lectures are presented here with an air of aloofness and, at
times, deliberate vagueness. In several places, especially when he
has to comment on the nature and movement of the heavens, Philoponus
breaks off and refers the student to previously published work: what
Philoponus *really* has to say about the text seems no longer
appropriate for the traditionally conceived class-room. He has shaken
off the weight of Aristotle's or anyone else's authority,
and far from attempting to demonstrate the harmony among philosophers
he puts himself forward as a philosopher who dissents from the
recognized philosophical authority. The commentator has turned into a
critic with independent philosophical ideas of his own.


## 3. The Critical Treatises


### 3.1 *On the Eternity of the World Against Proclus*




The Athenian Neoplatonist Proclus (ca. 411-485), the teacher of
Philoponus' own teacher Ammonius, had written a defense of the widespread conviction among
Greek philosophers that the
world is eternal. His aim was to demonstrate the untenability of Christian creationism. Proclus' eighteen arguments took their
point of departure from the myth of Plato's *Timaeus*, which,
according to Proclus, was best and most consistently interpreted
according to an eternalist reading: the surface talk of a world being
constructed by a divine 'demiurge' is part of the mythical and didactic framework, not an actual philosophical claim.



 In 529, the year when emperor Justinian put an end to pagan
philosophical teaching in Athens, Philoponus published a detailed reply
entitled *On the Eternity of the World against Proclus*. The
book amounts to an anti-commentary on the Proclean arguments: combing
through Proclus' text, Philoponus literally repudiates every single
point made. Although his efforts are evidently to some extent
motivated by his Christian faith, he keeps biblical theology out of
his polemic, attempting to refute Proclus within the framework of
Platonist philosophy. He reads the *Timaeus* as a genuine
account of creation (Book VI), compatible with Christian doctrine. A
new and ingenious analysis of the processes of generation and corruption renders
even an idea viable which Greek philosophers of all schools roundly rejected: creation out of nothing (Books VIII and IX). And even if it
is true, Philoponus retorts, that creation out of nothing never occurs in nature, God is
surely more powerful a creator than nature and therefore quite possibly capable of
*creatio ex nihilo* (IX 9).


### 3.2 *On the Eternity of the World Against Aristotle*




Philoponus' battle against eternalism may be divided into three
stages. The treatise *Against Proclus* is followed by a second
and even more provocative publication, *On the Eternity of the
World against Aristotle*. This work was published c. 530-534 and
involved a close scrutiny of the first chapters of Aristotle's
*On the Heavens* (his theory of ether as the fifth element, of
which the heavenly bodies are made) and the eighth book of the
*Physics* (arguing for the eternity of time and motion). The
third stage is represented by one, perhaps two, non-polemical
treatises that have survived in fragments which indicate that numerous
arguments against eternity and for creation were arranged in some kind
of systematic order.



 Like the polemic against Proclus, *Against Aristotle* is
mainly devoted to removing obstacles for the creationist. If Aristotle
were right about the existence of an immutable fifth element (ether)
in the celestial region, and if he were right about motion and time
being eternal, any belief in creation would surely be
unwarranted. Philoponus succeeds in pointing to numerous
contradictions, inconsistencies, fallacies and improbable assumptions
in Aristotle's philosophy of nature relating to these
claims. Dissecting Aristotle's texts in an unprecedented way, he
time and again turns the tables on Aristotle and so paves the way for
demonstrative arguments for non-eternity. One such argument is
reported by Simplicius (*In Phys.* 1178,7-1179,26 = *Contra
Aristotelem*, Fr. 132). It relies on three premises: (1) If the
existence of something requires the preexistence of something else,
then any one thing will not come to be without the prior existence
of the other. (2) An infinite number cannot exist in actuality, nor
be traversed in counting, nor be increased. (3) Something cannot come
into being if its existence requires the preexistence of an infinite
number of other things, one arising out of the other. From these not
at all un-Aristotelian premises Philoponus deduces that the conception
of a temporally infinite universe, understood as a successive causal
chain, is impossible. The celestial spheres of Aristotelian theory
have different periods of revolution, and in any given number of years
they undergo different numbers of revolutions, some larger than
others. The assumption of their motion having gone on for all eternity
leads to the conclusion that infinity can be increased, even
multiplied, which Aristotle himself held to be absurd.



 The non-polemical anti-eternalist treatises exploit, among others,
Aristotle's argument that an infinite power
(*dunamis*) cannot reside in a finite body
(*Phys.* VIII 10). Philoponus infers that since the universe is
a finite body, it cannot have the *dunamis* to exist for
an infinite time. As in the case of his theory of light, this argument
involves a not at all un-Aristotelian shift of meaning of the argument's central concept. There, *energeia* shifted from 'actuality' to 'activity'; in the context of Aristotle's argument in
*Phys.* VIII 10, *dunamis* meant 'power or kinetic
force', but Philoponus employs the word in the sense of
'capacity' or 'fitness to exist'.


## 4. Theological Treatises




 By the end of the 530s, as noted above (2.1), Philoponus seems to have stopped fighting
philosophical battles altogether; his career as a philosopher was
over. Thenceforward he devoted himself solely to writing on Christian theological
topics. Since there is no evidence that he belonged to the clerical
order, it is difficult to imagine the institutional context of his life as a
Christian theologian. He published his theological treatises under the same name
by which he had established himself as a commentator, *Ioannes ho
Grammatikos*, yet it seems hard to imagine him still working as a professor of grammar or literature in the Alexandrian system of higher education. His other epithet, '*philoponos*' (lover of toil) is probably
best interpreted as an acknowledgment of his literary productivity,
although it may also be an indication that he was one of a group of zealous Christian
brethren in Egypt who called themselves by that name.


### 4.1 *On the Creation of the World*




Perhaps some fifteen years after his attack on
Aristotle on the eternity of the world (the date is disputed), Philoponus published a
commentary on the biblical creation story, *On the Creation of the
World* (*De opificio mundi*), which is his only theological
work extant in Greek. While discussing the biblical text, Philoponus
frequently refers to philosophers like Aristotle, Plato and Ptolemy as
well as to Basil the Great, whose own treatise on the creation
served him as inspiration. The *De opificio mundi* has received
some attention from historians of science, because Philoponus suggests
at one point (I 12) that the movement of the heavens could be
explained by a 'motive force' impressed on the celestial
bodies by God at the time of creation. As we have seen (2.2 above),
Philoponus discussed impetus theory for the first time in the context
of trying to understand the physics of forced motion (Why does an arrow or stone continue to move after losing contact with its motive cause?). Now he
applies the same theory to the regular and natural motions of the universe at large. Significantly, Philoponus assimilates the supposed rotational impetus implanted by God into
the celestial bodies to the rectilinear movements of the elements as
well as to the self-movements of animals. The interesting upshot is that all these different types of natural and non-natural motions are understood in essentially the same way as impetus- induced movements. In virtue of this bold suggestion Philoponus is often
credited with having envisaged, for the first time, a unified theory
of dynamics, since he strove to give the same kind of explanation for
phenomena that Aristotle and others had to explain by appeals to different kinetic principles such as nature, coercion, or soul, depending upon context.


### 4.2 Monophysitism




Judging from the fragmentary evidence, Philoponus' later
theological treatises were characterized by a curious mixture of
Christian doctrine and Aristotelian philosophy. On the eve of the
fifth Council (Constantinople, 553) Philoponus stepped forward as a
partisan of monophysite Christology which, in the course of the
century, had become increasingly influential in the eastern part of
the Roman empire. For the monophysites it was important to emphasize the
divinity of Christ; they were alarmed by the bewildering conjunction of
Christological dogmas formulated at the Council of Chalcedon in
451. There Christ was confessed to be (1) consubstantial
(*homoousios*) with the Father, (2) consubstantial with
us humans, (3) one person and one *hypostasis* (an
important term widespread in Neoplatonism and roughly meaning
'substantive existence'), but (4) discernible in two natures
(*en duo phusesin 
gnorizomenon*), a phrase which was directly
influenced by the '*unitatem personae in utraque natura
intelligendam*' ('a unity of person knowable in both
natures') endorsed by the Bishop of Rome and familiar to
theologians of the Latin West. Although propositions 1, 2 and 3 were
no longer controversial, proposition 4 could be read as an unholy
concession to those who regarded Jesus as a human being merely
distinguished by some kind of divine presence or inspiration (the view
of the so-called 'dyophysites').



 In *Arbiter* (*Arbitrator* or *Umpire*), written about
the same time as the Council of Constantinople and surviving only in Syriac translation, Philoponus takes
the view that the locution 'discernible in two natures'
ought to be abandoned. His main strategy is to argue that in this
context the meaning of the terms 'nature' and
'*hypostasis*' are essentially identical, so that
if Christ is (according to (3)) one *hypostasis* he
cannot also (as in (4)) be discernible in *two* natures. The
argument goes roughly as follows: The term 'nature' has two
applications, one general and one particular: we can speak of the
nature of man in general or of the particular nature of this
individual man. Now, when one speaks of the unification (and
discernibility) of two natures in Christ, this cannot be meant to say
that the universal natures of godhead and manhood have been unified in
Christ (else it would be also true to say that not only the Logos, but
also the Father and the Spirit have become man, since the universal
nature of godhead applies to them as much as it does to the
Logos). Instead, the reference must be to the particular nature of the
divine Logos and the particular nature of Jesus the man: it must be
with reference to these particular natures that godhead and manhood
are combined in Christ. But this too cannot be right, Philoponus
claims, since 'particular nature' means the same as
'*hypostasis*', which he uses as a synonym also of
'person' and 'individual being'. Since it is
agreed that Christ is one person and one *hypostasis*,
he must consequently also be of one 'particular' nature
only, not two. Philoponus concedes, of course, that the nature of
Christ is not an ordinary one; it is complex, combining and preserving
the properties of both what it is to be a god and what it is to be a
man. Far from being able to discern two different natures in Christ,
we should speak of one complex or combined nature (*mia phusis
sunthetos*).


### 4.3 Tritheism




Besides monophysitism, Philoponus' name is associated with the
doctrine of tritheism. However, one needs to be aware of an important
difference: Whereas monophysitism was a reputable and powerful
theological movement in the Eastern church, tritheism was little more
than a hostile label given to certain intellectuals who tried to make
the mystery of the Trinity intelligible in philosophical
language. Philoponus was one such intellectual who, again, resorted to
Aristotelian terminology to clarify and settle the trinitarian
dispute. Already in the *Arbiter* it was clear that Philoponus
tended to understand the crucial term
'*hypostasis*' as meaning something like
'primary substance' in the sense of Aristotle's
*Categories*, i.e. an individual organic being. The fragments
of the very late treatise *On the Trinity* confirm this. Since
*hypostasis* is certainly not an accident of divinity,
Philoponus argues, it must be the case that the three
*hypostaseis* of the Trinity are three particular divine
substances with distinct properties. Only on this assumption, too, is
it reasonable to speak of the consubstantiality of the three Persons,
for if there were only one divine substance, what sense would it make
to speak of consubstantiality at all? When Basil and Gregory of Nyssa
spoke of the Trinity as 'one *ousia*, three
*hypostaseis*,' they were not, Philoponus
continues, enunciating four primary substances, but used
'substance' (*ousia*) in the secondary,
abstract sense of essence or universal nature. In accordance with
Aristotle, Philoponus claims that universals exist only in the
mind. Thus, the claim that there is only one God appears to be true of
the unity constituted by the *concept* of divinity. In actual
fact, there are three separate divinities, Father, Son, and Spirit. In
order to fend off any reminiscences of pagan polytheism, Philoponus
points out that unlike the individually differentiated gods of the
pagans the three divinities of the Trinity are all of the same, single
divine nature in the universal sense of 'nature'. It is important to keep in mind that so-called 'tritheists' like Philoponus would not have conceded that they thereby abandoned monotheism. Although
Philoponus had his followers, trinitarian philosophy of this kind
could hardly be palatable to anyone not committed before all else to
Aristotle's ontology. The so-called tritheists faced immediate and
severe criticism, and Philoponus himself was condemned by the Council
of Constantinople of 680-81. Only recently, his views seem to have received increased attention and appreciation among philosophically-minded historians of the Church (see Erismann (2008) and Zachhuber (2018)).




 Philoponus is often celebrated for having been one of the very
first thinkers to reconcile Aristotelian philosophy with
Christianity. To some extent, this is true, but crucially, his
contemporaries must have taken a different view. Pagan philosophers
abhorred the way in which Philoponus used Christianity as a vantage
point from which, in their opinion, he recklessly disturbed the
harmony of the Greek philosophers, and Christian theologians could not
but castigate his attempt to comprehend in Aristotelian terms what was
for them, essentially, a profound spiritual mystery demanding belief just because it was philosophically unacceptable.


## 5. Influence




Despite arousing the disapproval of many of his contemporaries, both
pagan and Christian, Philoponus' immediate influence may have been
considerable among fellow-monophysites in Egypt. The anathema of 681,
however, made the further proliferation of his theological ideas
impossible. Likewise, his arch-enemy Simplicius, also a pupil of
Ammonius, submitted the Grammarian's anti-eternalism almost
immediately to thundering pro-Aristotelian criticism (in his
commentaries on the *De Caelo* and the *Physics*,
written sometime in the late 530s). It was that polemic which
resounded through the ages; its shockwaves can still be felt in later
thinkers like Thomas Aquinas (1224-1274) and Zabarella (1533-1589) who
carefully examined, though in the end rejected, Philoponus'
anti-eternalist arguments. Philoponus' work was studied extensively
by the Arabs, who referred to him as Yahya an-Nahwi or
Yahya al-'Asqalani. Al-Kindi (ca. 800-870)
in particular is heavily indebted to Philoponus for his own attack on
eternalism. Later on in the West, the arguments against the eternity
of the world also persuaded Bonaventure (1217-1274) and Gersonides
(1288-1344), and impetus theory was reaffirmed by Buridan (1300-1361)
and his pupil Oresme (1325-1382). In the sixteenth century, the first
editions and numerous translations (into Latin) of Philoponus'
commentaries and the treatise *Against Proclus* began to appear
in print. Eventually, Philoponus' criticism of Aristotelian dynamics
in the *Physics* commentary was widely discussed and persuaded
such diverse thinkers as Gianfrancesco Pico della Mirandola
(1469-1533) and, for different reasons, Galileo Galilei (1564-1642). In a sense, Philoponus is a Renaissance figure *avant la lettre*. However, historically positioned at a half way point between the Classical period and the Renaissance, he symbolizes more than anything else the Western mind's excruciatingly slow struggle for emancipation from Aristotelianism on the one hand and blind faith in Church dogma on the other. 


## 6. 'Explaining' Philoponus




The greatest challenge for a student of this period of the history of
philosophy is to understand how a phenomenon such as Philoponus could
have occurred at all. To be sure, elusive individual qualities of his mind
and personality must have played an essential role, but it is
equally true that philosophical, social, and religious parameters are
likely to have supplied conditions which allowed him to carry forward
his unprecedented and unparalleled challenge to a widely
accepted intellectual tradition.  In the past, scholars have
readily pointed towards the presumed fact that Philoponus was first
raised as a Christian who later came into privileged contact with
Greek rationalism; it is supposed that this constellation catalyzed
his stance of critical opposition and rejection. However, this
explanation is far from satisfactory. Many Christians from birth both
before and after Philoponus were similarly exposed to pagan philosophy
without reacting in a comparable way. Other scholars have suggested
that Philoponus may have received orders from clerical superiors to
write a refutation of Aristotelianism. Again others, especially with a
view to the invention of the theory of impetus, have sought the roots
of Philoponus' intellectual emancipation in broad socio-economic
changes which occurred in late antiquity, in particular the
emancipation of slaves. In whichever way the epithet 'Philoponus' is eventually going to be
explained, it seems certain that what essentially enabled Philoponus
to operate both as a critic of Aristotelianism and as a constructive
thinker in his own right was somehow tied up with a new understanding of
what one ought to do when one is reading and interpreting the
philosophical texts of Plato or Aristotle. Whereas Neoplatonists,
especially since Proclus (412-485), tended to approach these ancient
texts as a fabric of venerable signs pointing *per se* and in
an infallible way to a higher reality and to the truth, Philoponus
read them (as we do today) as indicators of the thoughts and
intentions of fallible authors. His more measured hermeneutic
approach allowed Philoponus to point out problematic tensions, inconsistencies, and
glaring contradictions in the Aristotelian *corpus*, and to highlight
instances of substantive disagreement between Plato and Aristotle. In
contrast, the program of the Neoplatonic tradition he grew up in had been, largely,
either to ignore such hermeneutical problems or explain them away in an effort to harmonize the rich and diverse tradition of pagan Greek philosophy.