## 1. Life and Works




Giacomo (or Jacopo) Zabarella was born into an old and noble Paduan
family on the 5th of September in 1533. From his father
Giulio Zabarella he inherited the title of palatine count. Zabarella
enjoyed a humanist education and entered the University of Padua,
where he received the doctorate in 1553. Zabarella had many famous
teachers, like Francesco Robortello in the humanities, Bernardino
Tomitano in logic, Marcantonio Genua in physics and metaphysics, and
Pietro Catena in mathematics. Unlike most of his contemporaries who
had studied natural philosophy, Zabarella never took a degree in
medicine. His entire teaching career was spent at his native
university. He began his career in 1564 when he obtained the first
chair (or professorship) of logic succeeding Bernardino Tomitano. Five
years later he moved to the more prestigious and more lucrative second
chair of the extraordinary professor of natural philosophy. In 1577 he
was promoted to the first extraordinary chair of natural
philosophy. Finally, in 1585, Zabarella obtained the second ordinary
chair of natural philosophy, which he held until his death. The
statutes of the University of Padua prevented him, as a native Paduan,
from obtaining the first ordinary chair in natural
philosophy. Zabarella died at the age of 56 on the 15th of
October in 1589.




The publications of Zabarella reflect his teaching in the Aristotelian
tradition. The first of his publications was *Opera logica*,
which appeared in Venice in 1578. Zabarella had time to write this
collection of logical works in 1576, when a plague raged in Veneto
sending Zabarella into the countryside with his family. This was one
of the very few times in his life when he left the city of
Padua. Zabarella's next published work, *Tabula logicae*, came
out two years later and his commentary on Aristotle's *Posterior
Analytics* appeared in 1582. *De doctrinae ordine
apologia,* which appeared in 1584, was a reply to Francesco
Piccolomini who had criticised Zabarella's ideas on logic. The first
of Zabarella's works in natural philosophy, *De naturalis scientiae
constitutione*, came out in 1586. This introduction to the field
was connected to his major opus in natural philosophy, *De rebus
naturalibus*, the first edition of which was published
posthumously in 1590. It contained 30 different treatises on
Aristotelian natural philosophy and Zabarella wrote the introduction
of the book only few weeks before his death. Zabarella's two sons
edited his two incomplete commentaries on Aristotle's texts, which
were also published posthumously: the commentary on *Physics*
(1601) and the commentary on *On the Soul* (1605) (Mikkeli
1992, p. 19).




Giacomo Zabarella followed a very systematic style of writing in his
publications. His idea was to build a coherent body of Aristotelian
logic and natural philosophy. Therefore he was also interested in the
classification of the disciplines and the relationships between
various areas of academic learning. His use of Aristotle and other
authorities was both eclectic and critical. Zabarella's sources thus
included newly recovered Greek commentators such as Alexander of
Aphrodisias, Philoponus, Simplicius and Themistius, as well as
medieval commentators such as Thomas Aquinas, Walter Burley and
Averroes. In Zabarella's view, Averroes, unlike his followers,
accurately understood Aristotle's philosophy despite not knowing the
the original texts or even the Greek language (Martin 2007,
p. 15). Zabarella himself read Greek and could therefore consult the
Greek text of Aristotle and the commentators. He devoted much effort
to presenting what he considered to be the true meaning of Aristotle's
texts. However, he resisted the tendency of the humanists to expunge
all medieval barbarisms, preferring philosophical precision to
classical elegance (W.R. Laird 2000, p. 695).


## 2. Arts and Sciences




The Aristotelian distinction between arts (*artes*) and
sciences (*scientiae*) serves as the starting-point for
Zabarella's philosophical system. At the beginning of his *Opera
logica*, Zabarella draws a distinction between the eternal world
of nature and the contingent human world. From this distinction he
proceeds to two corresponding kinds of knowledge, and two distinct
methods of defining them. Zabarella maintained that, properly
speaking, sciences are concerned with the eternal world of nature and
thus are contemplative disciplines, whereas arts are concerned with
the contingent world of human beings and thus are non-contemplative,
being productive instead. The sciences in the proper sense of that
term, as pertaining to demonstrative knowledge, are limited to those
disciplines that deal with the necessary and eternal or with what can
be deduced from necessary principles. Zabarella notes that Aristotle
requires two kinds of certainty from science. One is in the knowable
things, which are necessary as such (*simpliciter*); the other
is in the mind of the scientist, who must be absolutely sure that
things cannot be otherwise. The necessity involved is therefore both
ontological, with respects to the objects known, and cognitive, with
respect to the knowing subject (Kessler 1998, p. 837).




The hierarchy of different disciplines was a widely debated topic in
Renaissance philosophy. Also Zabarella emphasized the hierarchical
nature of the division between different disciplines; the whole of
active philosophy aiming ultimately at the higher sphere of
contemplation. According to Zabarella, both in Plato and Aristotle
happiness in the active life is not the ultimate goal for a human
being. Instead it is contemplation, which is man's finest objective
that may lead to total perfection. In Zabarella's view the purpose of
active philosophy is to remove hindrance to the acquisition of
knowledge and therefore contemplative philosophy is the ultimate end
and master of all active philosophy. In productive disciplines (i.e.,
arts) it is not necessary to define the objects under production as
strictly as in the contemplative sciences, because the productive arts
do not aim at knowledge, and thus the knowledge they need do not have
to be perfect.




Zabarella identifies therefore the basic difference between arts and
sciences. Science deals with what already exists, but art is concerned
with creation. The subject-matter of a science is immutable, but the
subject-matter of an art is the formation of things as yet
non-existent, but which can be made by human being. The contemplative
philosopher is not interested in initiating anything, but rather wants
to comprehend and arrange the forms of existing, eternal things.
Moreover, the ultimate purpose of the contemplative science is the
pursuit of knowledge for its own sake, but in the productive arts the
end-result is an actual product (Mikkeli 1997, pp. 212-213).




However, Zabarella was not concerned solely with the separation
between the theoretical sciences and the practical and productive
disciplines, but dealt also with the relationships and hierarchy among
the theoretical sciences themselves. The contemplative or speculative
sciences, for Zabarella, are in Aristotelian manner only three in
number: divine science, also called metaphysics, mathematics, and
natural philosophy. Zabarella presents these contemplative sciences as
being the only defenders of true knowledge. Zabarella emphasised in
many instances that each speculative science should demonstrate their
own principles and not borrow them from metaphysics. According to
Zabarella, each discipline can be distinguished from others either
with respect to the object considered (*res considerata*) or
with respect to the way of considering (*modus considerandi*)
(Pozzo 1998). Natural philosophy, which deals with corporeal beings
that have an inner principle of movement, differs from metaphysics
(which contemplates being as being) and from mathematics (which deals
with abstracted beings) in both ways. As a result, natural philosophy
is autonomous and independent of both the other contemplative
sciences.




Zabarella also developed a theory of the middle (or mixed) sciences
that, contrary to the prevailing view, afforded sciences such as
astronomy and optics full demonstrative status despite their borrowing
principles from pure mathematics. Nevertheless, Zabarella's approach
to the study of nature remained causal and qualitative in the
traditional Aristotelian vein rather than mathematical. Therefore he
gave little attention to the possible uses of mathematics as a tool
for understanding the physical world (Laird 1983, Ch. 8).


## 3. The Nature of Logic




Zabarella's introductory treatise on the nature of logic, *De
natura logicae*, is basic to his teaching in logic. He defines
logic as being neither a science nor an art, but, in keeping with the
traditional meaning of the word *organon*, just an instrument
(*instrumentum*) of the arts and sciences. As an instrumental
discipline it furnishes a useful tool of inquiry for all the arts and
sciences. Logic does not have a real subject of its own, but deals
with concepts, which stand for real beings. In this it is comparable
to grammar. The difference between grammar and logic is that the
former is concerned with the perfect verbal expression of concepts,
and hence is a linguistic discipline, while the latter invents second
notions (*notiones secundae*) or second intentions, that are
able to create order among concepts. Therefore logic serves to
recognize the truth and distinguish it from falsehood in every
instance. Logic is thus a rational discipline (*disciplina
rationalis*) that is not itself philosophy, but springs from
philosophy and is devoted to philosophical ends (Vasoli 2011).




Zabarella followed Averroes in dividing logic into two parts:
universal logic, which is common to all subjects; and particular
logic, which is specific to particular subjects. The first three books
of Aristotle's Organon, the *Categories, On Interpretation* and
the *Prior Analytics* constitute the universal part of logic.
Aristotle's *Posterior Analytics, Topics* and *Sophistical
Refutations* are said to deal with particular logic as much as
they deal respectively with the demonstrative syllogism, the
dialectical syllogism and the sophistical syllogism. Following the
Neoplatonic commentators (above all Simplicius), Zabarella also
included Aristotle's *Rhetoric* and *Poetics* within
logic. The former is included because it teaches the use of the
rhetorical syllogism or enthymeme, and rhetorical induction or
example; the latter because it also teaches the use of example, not to
persuasive ends, but for imitation.




Since logic, viewed as the universal instrument for distinguishing
between the true and the false, differs according to the objects to
which it is applied and the ends for which it is used, its nature
depends on the realm of possible objects and ends. Rhetoric and
poetics are special cases because they deal not with knowledge but
with the political disciplines in so far as they are concerned with
the good of the people. Sophistical syllogistic is another special
case, because it is directed towards deception and prefers to use
falsehood as its material. Dialectic and demonstration, however, are
directed towards the expression of truth. Dialectic is aimed at the
production of opinion, and deals with probable and contingent
material; demonstration is dedicated to the acquisition of truth, and
so it is exclusively occupied with necessary, true objects (Kessler
1998, p. 837).


## 4. Orders of Presentation and Methods of Discovery




For Zabarella method also serves to differentiate the sciences from
the arts. The term can be understood in two ways, either in a wide
sense as a method of presenting existing knowledge, which he prefers
to call an order (*ordo*) of presentation, or in a narrow sense
as a method of discovering knowledge, for which he reserves method
(*methodus*) in its proper understanding. According to
Zabarella, *ordo* is an instrumental *habitus* through
which we are prepared so to dispose the parts of each discipline so
that the discipline may be taught as well and easily as possible.




As regards these methods of presentation, Zabarella denies Galen's
view that these are four in number. Zabarella himself recognizes only
two orders, the compositive and the resolutive. The order starts with
what is either necessary or useful for teaching and learning. In the
contemplative (or theoretical) sciences, which aim at perfect
knowledge, order of presentation follows the so-called way of
composition (*compositio*) from general principles to
particular beings; in moral philosophy and in the arts, which aim at
action or production, order follows the so-called way of resolution
(*resolutio*) from the desired end to its first principles.




For Zabarella the methods in the strict sense of the word are
intellectual instruments proceeding from the known to produce
knowledge of the unknown. Such methods have argumentative force and
they deal with specific problems of the disciplines instead of
arranging the contents of a whole discipline, as do the orders of
presentation. As with orders, Zabarella denied the possibility of more
than two methods. He shows that other procedures, like the
composition and division used in the hunt of definitions as well as
the so-called dialectical syllogisms are not genuinely productive of
knowledge and therefore not methods in the proper sense of the
term.




Therefore he recognized only two methods, which he labeled
demonstrative and resolutive. Demonstrative method (or composition)
proceeds from cause to effect and involves demonstration "of the
reasoned fact" or "most powerful" demonstration,
best exemplified in the mathematical sciences. Resolutive method (or
resolution) proceeds from effect to cause and, despite its name, also
involves demonstration, but of an inferior kind, that is called
demonstration "of the fact" or "from a sign".
Related to this alter type of demonstration is the process of
induction (*inductio*), which is helpful for discovering
principles that are known naturally but are not immediately
evident. Zabarella believes that, by the force of induction, human
intellect is capable of distinguishing the universal, which is hidden
in particulars. Induction, or resolutive method makes up the first
phase in the *regressus*-method, which was, in his opinion, the
only proper method for natural philosophy.




It is this very distinction between the method of inquiry and the
order of teaching that led Zabarella to a bitter controversy with his
Paduan college Francesco Piccolomini (1523-1607). They both agreed
that ethical inquiry must proceed by deduction from an understanding
of the end. In Zabarella's view all the disciplines whose end is
action should be explained in this same way. But Piccolomini could
not bring himself to admit that the order of teaching, in ethics as well
as in in other practical disciplines, should follow this order of
apprehension. Thus the fundamental question embedded in this dispute
is the following: Is the order of teaching a particular discipline
necessary or contingent? Zabarella argued for the former: both in
discovery and in teaching, one should follow the synthetic order in
the sciences and the analytic order in the arts. By making a sharp
distinction between the method of discovery and the order of teaching,
Piccolomini instead embraced a contingent view of pedagogical
method. Wishing to teach others, Piccolomini saw his duty as that of
starting out from first principles (*a primis principiis*). In
such a case it is better to begin with the simpler matters and
progress toward the end or goal. (Lines 2002, pp. 254-263)




Through their rival claims about *ordo doctrinae* Zabarella and
Piccolomini revealed as well very different perceptions of academic
and civil order, and very different ways of conceiving and pursuing
the office of philosopher within that order. Zabarella wholeheartedly
endorsed the purely contemplative nature of philosophy and the
superiority of the contemplative life (Mikkeli 1992, pp. 25-35). He
also was frequently dismissive in his treatment of the disciplines he
regarded as active or operative, for example law, medicine, ethics,
politics and mechanics. Piccolomini's position was sharply
opposed. For him, philosophy is, indeed, crucial for the spiritual
perfection of man. However, in the form of *scientia civilis*
it is also the key to the this-wordly perfection that can be attained
in the just administration of the Venetian republic (Jardine
1997).


## 5. The *Regressus*-Method




The so-called *regressus-*method is a model for combining
composition and resolution: the idea of this combinatory process is
found in the Aristotelian tradition from Averroes on, and it was
vitally revived among the Italian Aristotelians and medical authors.
According to this method, the natural philosopher should first infer
from the known effect the existence of the cause of this very effect.
Sometimes he may use induction, but usually resolution, which was also
called *demonstratio quia* or demonstration from the fact. Then
in the second step, in the so-called *demonstratio propter
quid* or demonstration from the reasoned fact (or composition),
the natural philosopher should infer from the cause to the effect. The
effect is now known through its cause, and hence in a scientific
manner (Risse 1983). The crucial problem with this procedure is how to
avoid mere circular reasoning, or rather, how to make sure that the
cause, whose existence is demonstrated in the first step, is indeed
the cause of this very effect. From the beginning of the sixteenth
century, it had become clear that it was necessary to introduce a
third, intermediary step, which involved some kind of intellectual
consideration (*negotiatio intellectus*) (Kessler 1998,
p. 838).




Zabarella also had to face the question, how the intellect in fact
made this mental consideration. He solves the problem in terms of his
psychology of knowledge and calls this third step a mental examination
(*examen mentale*). Since for him the task of this intermediary
step is to make distinct the confused knowledge of the cause that was
acquired through the first step, he refers to his work on the agent
mind (*Liber de mente agente*) in which he develops an account
of the transformation of confused into distinct knowledge through the
analysis of a given whole in terms of its parts. He presents this
process as the specific ability of the human mind. Thus once more
method as a means of acquiring knowledge is based on the cognitive
structure of knowing subject rather than on the ontological structure
of the object of knowledge. In his commentary on the *Posterior
Analytics* Zabarella identified Aristotle's proofs that the
planets are near and that the moon is a sphere as instances of the
*regressus-*method. Other examples of the same method he
analyzed are Aristotle's proof of the existence of "first
matter" (*materia prima*) from substantial change and his
proof of an "eternal first mover" (*primus motor
aeternus*) from local motion (Wallace 1999, p. 338).




The interminable discussion of the methodology of arts and sciences in
the sixteenth century may be seen as an attempt to defend the
scientific status of either the recently found autonomous sciences,
like natural philosophy, or, on the other hand, the empirically based
productive arts. The discussions of orders and methods, resolutions,
compositions and the *regressus*-method are, therefore, not
merely further elaborations of an old Aristotelian tradition, but also
expressions of opinions in a lively debate concerning the changing
relationships between various arts and sciences in sixteenth-century
Italian universities (Mikkeli 1997, p. 228).


## 6. The Science of the Soul




The most influential section in the Aristotelian tradition, where the
relationship between the theoretical or speculative sciences is dealt
with, is the beginning of Aristotle's treatise *On the Soul.*
Aristotle gives two criteria for the hierarchy: the dignity of their
subject-matter and the exactness of their demonstrations. In his
posthumous commentary on *De anima* Zabarella raises the
question of the hierarchy of the sciences. In most cases, in
Zabarella's view, the science with a nobler subject-matter can be
considered superior, but not always. All human knowledge can be
compared and there are no grounds for giving either of these criteria
absolute priority. In the contemplative sciences the nobility of the
subject-matter should be considered superior to the causality of
knowledge. In logic, however, where the instruments of science are
considered, the nobler instrument is the one that is more precise and
produces more certain knowledge.




Zabarella, then, did not give one decisive criterion according to
which all arts and sciences could be arranged into one single
hierarchy. However, when dealing with the place of the science of the
soul among the other sciences, Zabarella gives an description of the
nobility of this part of natural philosophy. Zabarella opposed the
definition of the science of the soul as a middle discipline between
physics and metaphysics. He states that Aristotle did not only wish to
compare the science of the soul with other sciences, but to compare it
with other parts of natural science. In Zabarella's view it is obvious
that the science of the soul is the most noble part of natural
philosophy, the king and emperor of every other part, which are all
dependent upon it, because it shows the first cause and the sum of
everything that is in animals and in plants. The science of the soul
is more exquisite and certain than all the parts of natural
philosophy, because the causes of the science of the soul are more
exact, not only to us, but also according to nature (Mikkeli 1997,
p. 220).




Zabarella's position here can be interpreted as an attempt to raise
the status of an independent natural philosophy by emphasizing the
nobility of the science of the soul. In fact, it seems that he wanted
to elevate the status of *De anima* to that of a special
science among other natural disciplines that is the noblest and most
precise of all natural sciences on which all the other parts of
natural philosophy could rely. What in the medieval times had perhaps
been considered to be part of metaphysics was now the most valuable
part of natural philosophy. Following the Alexandrian tradition,
Zabarella himself left the question of the immortality of the soul to
the theologians, because it did not belong to natural philosophy, and
since Aristotle, as a natural philosopher, had not been explicit about
it (Kessler 2011, p. 52). It is, in fact, hard to be sure, whether
Zabarella himself thought that the soul was mortal. However, in his
commentary on Aristotle's treatise *On the Soul* Zabarella
tried at least to prove that Aristotle himself did not consider it
immortal (Mitrovic 2009; Valverde 2012).




Zabarella reconstructed the process of intellection on the lines of
sense-perception, that is that the intelligible *species*,
produced concurrently by the *phantasma* and the illuminating
agent intellect, moved the possible intellect into cognition. To be
known, the *phantasma,* which was gained by sense-perception,
had to undergo a double process. Itself material and consequently
containing the universal structure needed in science only in a
confused and unintelligible way, it had to be illuminated by the agent
intellect, so that the universal in the individual was rendered
distinct and intelligible. Since the illumination was generally
required for any act of knowledge in the same way, its agent did not
have to be an individual operating individually in the different acts
of intellection, but rather could be an universal one, which rendered
reality in general intelligible, thus serving as an all-embracing
guarantee of intelligibility. The agent intellect could therefore be
identified with God himself as the principle of intelligibility. When
identifying the active intellect with God as the first cause of all
that exists and can be known, Zabarella has clearly in his mind that
the active intellect does no longer play a substantial role in this
naturalistic philosophy of nature after this initial act of intellection (Kessler 2011, pp. 56-57).




Therefore with the metaphysical requirements of intellection taken for
granted, the main epistemological problem shifted to the manner in
which the intelligible *species* was turned into a known
object. Zabarella, considering the agent intellect as the divine
cause of general intelligibility, could renounce innate principles and
retain the Aristotelian teaching of the inductive acquisition of the
first principles themselves. But Zabarella had instead the problem of
restoring to the human mind an active faculty which would account for
the act of judgement. Therefore he redefined the possible intellect as
an active faculty as well. This equally active and passive human
intellect (which Zabarella called *patibilis* instead of
*possibilis*) considered all that was offered to it by the
illuminated *phantasma*, contemplated whatever it wanted to,
and in doing so selected and abstracted those structures it wished to
know and through judging understood them and became itself the object
of knowledge. For Zabarella intellection therefore was not a process
automatically determined whenever an exterior impulse was given, but
rather depended essentially on human will and intention. In
Zabarella's view, the science of the soul was concerned with what was
necessary and therefore always equally present in any human mind, even
if unconsciously. Methodology, on the other hand, was concerned with
the use a human being made of these natural faculties. Since this use
could be true or false, better or worse, truth and error depended
entirely on whether or not the correct method was being used (Kessler
1988, pp. 530-534).


## 7. The Perfection of the Philosophy of Nature




Natural philosophy has to know and teach the very essence of natural
beings. First, it has to deal with their basic principles, such as
matter and motion, which are not natural beings themselves. These
principles of natural philosophy are discussed in Aristotle's
*Physics*. Moreover, natural philosophy has to deal with the
accidents of natural beings understood through their causes. These are
the subject of Aristotle's other writings on nature, from *On the
Heavens* to *On the Soul* (on Zabarella's ideas
on *Physics*, see Biard 2005).




In *De naturalis scientiae constitutione*, the first treatise
in his collected works on natural philosophy (*De rebus
naturalibus*), Zabarella deals in detail with the questions of the
order and perfection of the natural sciences. He claims, for example,
that the book on minerals is necessary because the natural philosophy
would otherwise be incomplete. The place of the book on minerals in
Aristotelian *corpus* on natural philosophy is immediately
after the book *On Meteorology.* Whether Aristotle himself
wrote on minerals is questionable, but he at least recognized the
importance of the subject. However, later both Theophrastus and
Albertus Magnus wrote on this important subject. Thus Zabarella did
not consider Aristotle's works as a complete *corpus* to which
nothing could be added. In *De methodis* Zabarella states that
Aristotle wrote on subjects of his own choice, but it would be an
exaggeration to claim that he was incapable of making
mistakes. Aristotle was not infallible and it would be erroneous to
insist that he knew the truth of everything he wrote. Nevertheless, he
was an outstanding scholar in Zabarella's view, who, for example,
turned the study of logic into a discipline.




In the last chapter of *De naturalis scientiae constitutione*
Zabarella discusses the question of the perfection of the natural
sciences (*De perfectione scientiae naturalis ac de eius
ordine*). Zabarella states that Aristotle's philosophy of nature
may be perfect in structure and form, but it is incomplete in terms of
its reference to natural beings. There is much Aristotle did not
discuss at all and indeed much that was outside his cognisance.
Although he dealt comparatively little with plants and animals, it is
not difficult to pinpoint their proper palces in the Aristotelian
system of the natural sciences. Therefore Zabarella emphasizes that
Aristotle's philosophy of nature is complete at least in theory.
Zabarella compares Aristotle's works on natural philosophy to the
geometry and arithmetic of Euclid. There are many theorems which can
be demonstrated from his works even if he did not himself actually
write them. For Zabarella this is no reason to judge Euclid's geometry
or arithmetic defective or incomplete. If Euclid had wished, he could
have demonstrated all the particular cases, but his book would have
become so enormous that it surely would have daunted the reader.
Zabarella suggests that this is exactly why Euclid entitled his book
*The Elements*, and from this foundation all the other theorems
can be demonstrated.




In parallel view Zabarella thinks that Aristotle's natural philosophy
can be called perfect, since it deals with all the knowledge that is
possible for human intellect to obtain, either in practice or at least
in theory. Also in his logical works Zabarella emphasizes the idea of
a perfect natural philosophy, which consists of a perfect and distinct
knowledge of natural beings through their causes. Zabarella reminds
that scientific knowledge can never be called confused or
imperfect. Therefore the scientific ideal Zabarella presents is
profoundly different from the modern view of a scientist making new
discoveries. According to Zabarella, science can be "new"
only in a restricted sense; the work of a scientist is more like
correcting the mistakes and filling the gaps in a ready-made
Aristotelian world-system (Mikkeli 1992; 1997, pp. 214-215; 2010,
p. 189)


## 8. Natural Philosophy and Medicine




Among the Paduan Aristotelians Zabarella was probably the author who
discussed most thoroughly the relationship between the philosophy of
nature and medical art. While in subject-matter these disciplines were
close to each other, in their essence and methodology they were far
apart. Unlike many of his contemporaries, Zabarella did not consider
medicine to subalternated to the philosophy of nature. Nor did he see
the distinction between theoretical and practical medicine as
accidental; instead he wanted to consider the whole art of medicine as
operational. In spite of medicine's prominent place among the arts;
Zabarella sharply denied its scientific status, and insisted that
writers who claim that medicine is a science are mistaken. Neither the
art of medicine nor its singular parts can be considered as science.
For him it was enough to admit that it is the noblest of all arts.




In his *De natura logicae* (part of the *Opera logica*)
Zabarella attacks writers who put medicine alongside the philosophy of
nature among the sciences. Contemplative philosophy appropriates
nothing from the productive arts, but instead the arts adopt
everything from philosophy. No matter how valuable and precise
medicine may be, it could never be a science because it is practised
not for the sake of knowledge, but for an end product: that is, the
maintenance or restoration of health. If knowledge of the human body
is considered purely for its own sake, rather than for curative
purposes, it should be called natural philosophy rather than
medicine. Even if it were admitted that medicine could be practised
for the sake of knowledge, it could not be called a pure science,
because it does not explain the first causes, and without this
comprehension the other causes cannot be clearly apprehended. Health
cannot be fully comprehended and the goal of medicine cannot be
achieved, if a physician does not comprehend all the parst of a human
body and their nature, composition, purpose, and function.




Zabarella recognizes two different ways in which a physician can know
the parts of a human body. First, he may learn them through perceptive
knowledge and anatomical observations, thereby assimilating the matter
of his discipline without understanding its rationale. A physician can
also become familiar with the parts of human body through philosophy
of nature where he may learn the reasons, which lie behind what he
actually sees. Zabarella thinks Aristotle made the same distinction in
his books the *History of Animals* and the *Parts of
Animals.* In the first he relies on sense perception to classify
the different parts of animals. In the second, he offers causal
explanations for what he is considering. In Zabarella's opinion this
order of understanding results from our own inability to comprehend
everything at once. It is thus better to progress gradually from
confuse to distinct knowledge. In *De rebus naturalibus*
Zabarella points out that the art of medicine adopts the physiological
part from the philosophy of nature. If medical writers want to know
the anatomy of the human body, they must therefore follow Aristotle
methodologically. Therefore they should not study the *History of
Animals*, but instead the *Parts of Animals*, which shows
us the functions of different parts of the bodies in question. The
subject-matter of medicine involves maintaining or recovering health
only in human beings, not in other animals. Since the whole discipline
deals only with the human body, it cannot be a science in Zabarella's
view. What a natural philosopher writes about animals, a medical
writer should apply to human beings.




Zabarella moves from the universal and scientific discussion of
natural philosophy to a consideration of its particular aspects from
the standpoint of operation, not knowledge. Moreover, Zabarella
believed that natural philosophy and medicine differ not only in their
aims and subject-matters, but also in their methods. The resolutive
method is proper to medicine and the compositive method to the
philosophy of nature. A physician does not use demonstrations, and if
he does, he borrows them from natural philosophy. In medical art the
resolutive order of presentation proceeds from knowledge to cure. The
end, that is maintaining or recovering health, is broken down into
principles, on which the operation is then based. In the order of
presentation Zabarella wants to differentiate between the presentation
of a whole discipline and that of a part of it. For example, the first
part of the art of medicine, physiology, has a compositive order as
against the medicine as a whole, which is arranged according to a
resolutive order. In Zabarella's view this shows that physiology
does not really belong to medicine at all, but to natural philosophy,
because in physiology the nature of a human body is studied apart from
operation.




Zabarella's conclusion about the relationship between the art
of medicine and natural philosophy is that the latter must consider the
universal qualities of health and sickness, while the former
concentrates on finding remedies for particular diseases. Zabarella
suggests that Aristotle wrote a book of health and sickness of which
nothing but a small fragment remains. These fragments are on the
borderline of these two disciplines. Zabarella sums this up: where the
philosopher ends, there the physician begins (*ubi desinit
philosophus, ibi incipit medicus*). From the universal
consideration of sickness and health the physician descends to the
treatment of all particular diseases and to knowledge of their causes.
While discussing the principles of medical art Zabarella compares
anatomical principles with principles derived from natural philosophy.
In his view, only the philosophy of nature, not anatomy, can provide a
solid basis for medical practioners (Mikkeli 1997, pp. 221-225).


## 9. Aftermath




From the things considered above, it becomes clear that Zabarella
cannot be considered as a precursor of modern experimental science. In
spite of its empirical basis, Zabarella's natural philosophy is not
concerned with anything akin to experiment. Indeed, if experiments
were to be developed, they would find their place in the productive
arts rather than in natural philosophy. Zabarella did not use
experiments in order to verify or falsify theories in the modern
sense. (Schmitt 1969) However, he made observations of natural
things, but they were just made to exemplify and illustrate the
demonstrative reasoning used in the theoretical natural
philosophy (Rossi 1983, p. 146).




During the past decades Zabarella's name has been linked to modern
science. John Herman Randall published already in 1940 (and again in
1961) his famous idea on "the School of Padua" that would
have been the precursor of modern science. Following Ernst Cassirer,
Randall referred to the Renaissance discussions of
*regressus-*method up to Zabarella as a preparation for Galileo
Galilei's new method of natural science. However, the Aristotelian
terminology and doctrines that Zabarella and Galileo share, seem for
the most part to have been commonplaces of late medieval and
Renaissance thought. Galileo may have known Zabarella's writings, but
far more important source for Galileo was the Jesuit scholars, above
all Paolo della Valle, working at the Collegio Romano at
Rome (Wallace 1999, p. 338).




Instead of overemphasizing the connection between Zabarella and
Galileo, it should be noted that Zabarella's thought had a large
impact among Protestant Aristotelians in Germany and in the Low
Countries during the late sixteenth century and first part of the
seventeenth century (Backus 1989; Maclean 2002). Zabarella's books
were known even in the remote Scandinavian countries surprisingly
early already at the turn of the seventeenth-century (Mikkeli
2002). Zabarella's clear and systematic interpretation of Aristotle's
logic and natural philosophy was used as a basis for numerous
Aristotelian textbooks printed in Germany. Moreover, the Protestant
academics found Zabarella's instrumentalist view of logic useful for
their theological purposes (Kusukawa 2002). Also in the British Isles
the Scholastic revival of the early seventeenth century owed much to
Zabarella's writings (Sgarbi 2012; Sgarbi 2013, 53-78). Recently
there has been some considerations whether Zabarella's distinction
between the objects of science (*res considerata*) and the way
of considering (*modus considerandi*) had an impact on the
distinction between matter and form in Immanuel Kant's philosophy
(Sgarbi 2010). Even some modern scholars of Aristotle have still
consulted his commentaries with profit.