John Buridan (Stanford Encyclopedia of Philosophy)

First published Mon May 13, 2002; substantive revision Mon Jul 10, 2006

Perhaps the most influential Parisian philosopher of the fourteenth
century, John Buridan did much to shape the way philosophy was
practiced not only during his own lifetime, but throughout the later
scholastic and early modern periods. He spent his entire career as a
teaching master in the arts faculty at the University of Paris,
lecturing on logic and the works of Aristotle, and producing many
commentaries and independent treatises on logic, metaphysics, natural
philosophy, and ethics. His most famous work is the Summulae de
dialectica (Compendium of Dialectic), a text of astonishing
breadth and originality aimed at redeeming the older tradition of
Aristotelian logic using the newer, terminist logic of
‘moderns’ such as Peter of Spain and William of Ockham.
Buridan applied these analytical techniques so successfully in his
metaphysics, physics, and ethics that, for many of his successors,
they came to be identified with the very method of philosophy,
understood as a secular practice, i.e., as distinct from
theology.

1. Life
2. Writings
3. Language
4. Logic
5. Metaphysics
6. Natural Philosophy
7. Ethics
Bibliography

1. Life

John Buridan was born sometime before 1300 at or near the town of
Béthune in Picardy, France. He was educated in Paris, first at
the Collège Lemoine, where he was awarded a benefice or stipend
for needy students, and then at the University of Paris, where he
received his Master of Arts degree and formal license to teach by the
mid-1320s. He enjoyed a long and illustrious career as an arts master
at Paris, serving twice (in 1328 and 1340) as university rector and
supporting himself with numerous benefices. He last appears alive and
well in a document of 1358, which mentions him adjudicating a
territorial dispute between the English and Picard nations (the
Parisian student body at the time was organized according to one’s
place of origin). He must have died shortly thereafter because in 1361,
one of his benefices was awarded to another
person.^[1]

Such is the historical record — a handful of relatively minor
details.^[2]
Buridan’s fame as a teacher and philosopher,
however, quickly turned his life into the stuff of legend. There are
stories that he met his end when the King of France had him thrown into
the Seine River in a sack because of a scandalous affair with the
Queen, that he went on to found the University of Vienna after being
expelled from Paris for his nominalist teachings, and that he even hit
the future Pope Clement VI over the head with a shoe while competing
for the affections of the wife of a German shoemaker (the blow
apparently created the prodigious memory for which Clement was widely
known). But none of these stories can be independently verified, and
most are inconsistent with what we do know about
him.^[3]
Nevertheless, they illustrate what the French scholar Edmond Faral
called the “bruits de ville” or ‘buzz’
surrounding Buridan’s name in Parisian circles, which continued for
some time after his
death.^[4]

Buridan’s academic career was unusual in two respects, both of which
help to explain his philosophical outlook. First, he appears to have
spent his entire career in the faculty of arts, without moving on to
study for a doctoral degree in one of the higher faculties of law,
medicine, or theology — the more typical career path in medieval
academia. Most of the figures we think of today as medieval
philosophers were in fact trained as theologians, including Thomas
Aquinas, Duns Scotus, and even William of Ockham (though he did not
finish his degree). Since university statutes forbade arts masters
from teaching or writing about theology, Buridan produced no
theological works and no commentary on the Sentences of Peter
Lombard, the principal genre of philosophical writing in the
fourteenth century.

Why did Buridan remain in the faculty of arts? It is unlikely that
someone of his obvious philosophical abilities would have gone
unnoticed. Nor does the reason appear to have been a lack of means,
for despite his impoverished background he did receive a number of
bursaries and stipends, and is even listed in a document of 1349 as
being among those masters capable of supporting themselves without
financial assistance from the University. One possible answer —
though in the absence of concrete evidence that he never studied
theology, it must remain speculative — is that he deliberately chose
to remain among the ‘artists [artistae]’. What
little he does say about philosophy very clearly ties the
philosophical enterprise to his office as an arts master, not to
whatever it was the theologians took themselves to be doing.
Rejecting the traditional picture of theological learning as the
perfection or completion of philosophical wisdom, Buridan seems to
articulate, perhaps sometimes in spite of himself, a new vision of
philosophy as a secular enterprise based on what is evident to the
senses and intellect, in contrast to theology, which begins from
non-evident truths revealed in scripture and doctrine. Perhaps most
tellingly, Buridan never refers to theology as constituting a
‘scientia’, or body of
knowledge.^[5]

Buridan is also different in that he remained for his entire life a
secular cleric rather than joining a religious order such as the
Dominicans or Franciscans. A papal letter of 1329 refers to him as
simply, “clericus Atrebatensis diocoesis, magister in
artibus [a cleric from the Diocese of Arras and Master of
Arts]”.^[6]
By contrast, the best-known names from the period all had religious
and intellectual affiliations beyond the university: Thomas Aquinas
(Dominican), Duns Scotus (Franciscan), William of Ockham (Franciscan),
Gregory of Rimini (Augustinian), to name a few. The benefit for
Buridan was that it freed him from the obligation to enter into the
doctrinal disputes that had begun to arise, with alarming frequency
and intensity, between religious orders, or between an order and the
church hierarchy — e.g., the dispute between the papacy and the
Franciscans over apostolic poverty. Thus, whereas Ockham spent his
entire later career on political crusades, away from philosophy, and
was finally excommunicated for his troubles, Buridan was bound only by
the intellectual and pedagogical traditions of his university. His
confessional independence also meant that he could help himself to
philosophical insights from a variety of sources. This emerges in the
sometimes eclectic character of his work, as we shall see below.

2. Writings

Most of Buridan’s works are in the form of commentaries on
Aristotle. He wrote both expositiones (expositions), or
literal commentaries consisting of detailed, line-by-line explanations
of the meaning of Aristotle’s words, and quaestiones
(questions), or longer, critical studies of the philosophical issues
raised by them, usually centered on a specific lemma from the text.
Both genres originated in the classroom, a fact that becomes clear in
the references to student queries and student concerns that survive in
the written versions. Like teachers in our own day, Buridan would
lecture more than once on the same text over the course of his career,
with the result that there are sometimes different versions of his
commentary on the same work. For example, there are three versions of
his Quaestiones on Aristotle’s De anima, the last of
which identifies itself as the “third or final lecture
[tertia sive ultima lectura]”. Where there are multiple
versions of the same commentary, their relationship is generally one
of increasing length and sophistication over time.

Buridan commented on virtually all of the major works of Aristotle.
In addition to the entire Organon, there are commentaries on
Aristotle’s Physics, On the Heavens, On
Generation and Corruption, De Anima, Parva
Naturalia, Metaphysics, Nicomachean Ethics, and
Rhetoric.^[7]
He also wrote a number of shorter, independent treatises on
controversial philosophical topics, such as the Tractatus de
relationibus [Treatise on Relations], Tractatus de
universalibus [Treatise on Universals], Tractatus de
consequentiis [Treatise on Consequences], and Quaestio de
puncto [Question on Points]. He was a very
prolific author.

But Buridan’s masterwork is the Summulae de dialectica
[Compendium of Dialectic], a comprehensive logic textbook that started
out as a commentary on the Summulae logicales or logical
compendium of the thirteenth-century dialectician, Peter of
Spain,^[8]
but soon evolved into an independent work of astonishing breadth and
originality. In it, Buridan redeems the older medieval tradition of
Aristotelian logic through the via moderna [modern way] —
i.e., the newer, terminist logic that had gradually replaced
it. Because the work was accessible to master and student alike, it
became extremely popular at Paris and in newly founded universities
such as Heidelberg, Prague, and Vienna.

Buridan’s other works were almost as widely read as the
Summulae. Handwritten copies and early printed editions were
carried by his students and followers throughout Europe, where they
were often used as primary texts in university courses on logic and
Aristotelian philosophy. The via Buridani continued to shape
European thought well into the Renaissance.

Like other medieval philosophers, Buridan has not been fully
appreciated because of the lack of modern editions and translations of
his work (see bibliography). The situation has improved recently with
the appearance of Gyula Klima’s mammoth translation of the entire
Summulae from the (now almost complete) Latin critical edition
of the text. But knowledge of Latin and the ability to read medieval
manuscripts are still essential if one wishes to study Buridan’s
thought first-hand.

3. Language

In the medieval university, arts masters provided students with their
basic education in grammar, logic or dialectic, and Aristotelian
philosophy, subjects that embodied the ideals of literacy and learning
in the Middle Ages. What they taught is perhaps best understood as a
specialized language of rational inquiry, which became the foundation
for further study in the faculties of law, medicine, and
theology. Students were required to learn, in ascending order, the
exposition and interpretation of authoritative texts (grammar), the
structure and modes of argumentative discourse (logic), and finally,
the systematic analysis and investigation of the order of nature
(Aristotelian philosophy). Although he did not write grammatical
treatises,^[9]
Buridan asserts in the very first section of the Summulae
that “positive grammar [grammatica positiva] has to be
learned first, by means of which the master is able to communicate
with the disciple, whether it be in Latin, French, Greek, or Hebrew,
or whatever else” (S 1.1.1: 6). The disciple’s knowledge of
logic and Aristotelian philosophy is built upon this grammatical
foundation.

The importance of language in Buridan’s philosophy emerges on many
levels, all of which are driven by his pedagogical aims. In logic,
grammatical rules are explicitly subsumed as necessary conditions of
the science (scientia) of logic, so that although the
logician’s notion of truth and the grammarian’s notion of congruence
are separable in theory, in practice the complete significance of a
piece of discourse cannot be determined without both. Context is
crucial to interpretation:

We should also note that some might ask whether it is the
composite or the divided sense that is properly expressed by
‘Every man or (a) donkey runs’, that is to say, whether
only the term ‘man’ or the whole subject is distributed.
And I say that we have to respond differently, in accordance with the
different manners of speaking and writing. For if immediately after
‘man’ there is a sign of division, namely, a pause or a
period, then the proposition will be called divided, and only
‘man’ will be distributed, but if not, then it will be
called ‘composite’, and the whole subject will be
distributed. (S 4.2.6: 250; cf. S 9.4, 15th sophism:
912-13).

Accordingly, logic is not about some conceptually ideal or canonical
language but the practical art of interpreting actual human discourse:

an utterance [vox] does not have any proper import
[virtus propria] in signifying and suppositing, except from
ourselves. So by an agreement of the disputing parties, as in
obligational disputes, we can impose on it a new signification and not
use it according to its common signification. We can also speak
figuratively [transsumptive] and ironically, according to a
different signification. But we call a locution ‘proper’
when we use it according to the signification commonly and principally
given to it, and we call a locution ‘improper’ when we use
it otherwise, although we can legitimately use it otherwise. So it is
absurd to say that a proposition of an author is false, absolutely
speaking, if he puts it forth incorporating an improper locution,
according to which it is true. Instead, we ought to say that it is
true, since it is enunciated according to the sense in which it is true
… So it absolutely seems to me that wherever it is evident that
an author puts forward a proposition in a true sense, although not as a
proper locution, then to deny that proposition without qualification
would be cantankerous and insolent [dyscolum et protervum].
But to avoid error, it should be properly pointed out that the
proposition is not true in the proper sense, or by virtue of its proper
meaning, and then it has to be shown in which sense it is true. (S
4.3.2: 256; cf. QIP 5: 144-145, ll. 800-829)

In Buridan’s view, the logician cannot expound the meaning of a
proposition without carefully attending to its internal features, i.e.,
the sense of the particular locutions incorporated in it, as well as to
its external features, i.e., the discourse conditions that surround
it.

This willingness to take human language as it is found, with all of
its ambiguities and rough edges, marks an important difference between
Buridan and Ockham, the fourteenth-century philosopher with whom he is
most often compared. Both make the traditional assumption that
propositions, be they spoken, written, or mental, are the bearers of
truth and falsity. Ockham, however, tends to see mental propositions
as logically ideal or, in modern parlance,
‘canonical’.^[10]
The problem with spoken and written propositions is that because they
depend on the meaning conventions of fallible users, they fail to be
universal and logically perspicuous. Thankfully, these shortcomings
can be filtered out metalinguistically once we realize that the
meanings of their constituent terms depend on their corresponding
mental concepts, which naturally signify the same for everyone. So in
Ockham’s logic, the semantic relation between these concepts and what
they signify outside the mind is of paramount importance; spoken and
written terms have semantic properties too, of course, but in an
entirely derivative way. By contrast, Buridan never privileges
conceptual discourse or suggests that the logician might use it
systematically to reform spoken or written language. He holds that
spoken and written utterances — sometimes he uses the term
‘utterance [vox]’ where Ockham has ‘term
[terminus]’ — signify concepts primarily: “the
capability of speaking was given to us in order that we could signify
our concepts to others and also the capacity of hearing was given to
us in order that the concepts of speakers could be signified to
us” (S 4.1.2: 222). Accordingly, “utterances are imposed
to signify things only through the mediation of the concepts by which
those things are conceived” (QC 1: 4, ll. 45-6). Concepts are
just the medium of signification for Buridan, the cognitive or
psychological aspect of the signification of a word.

This difference helps to explain why Buridan uses paradoxes of
self-reference to test the functionality of his logic, whereas Ockham
avoids them by claiming that a term — or at least a term in those
circumstances — cannot refer to
itself.^[11]
Buridan takes seriously the fact that people can and do utter
self-referential propositions, and thinks logicians should say what is
going on when they do. This is really a difference of perspective. As
Joël Biard has pointed out, we can divide medieval logicians into
those who try to restrict the possibilities of human discourse in the
direction of what is logically ideal, and those who are willing to
accept a proposition because it is grammatical and because the person
who utters it intends to signify something by it. Ockham, William of
Sherwood, and Walter Burley belong to the former group; Buridan and
Thomas Bradwardine to the
latter.^[12]
It also explains why Buridan tells us that it is not possible to
analyze contradictory propositions unless they “have the same
subject and predicate in utterance and also in intention” (S
9.7, 2nd sophism: 943), and his reminding us that, when testing a
proposition for contradictoriness, “it is [sometimes] necessary
to add other utterances when contradicting it…. For one should
primarily attend to the intention, for we use words only to express
the intention” (S 9.8, 11th sophism: 979). The logician must
above all be a skilled interpreter of human discourse.

For Buridan, linguistic confusion is the source of many of the
traditional problems of metaphysics and natural philosophy. His
approach is broadly nominalistic, but Buridan’s nominalism is more of
a parsimonious way of doing philosophy than a doctrine about the
ontological or metaphysical status of universals. For example, when a
cause is understood as being actual rather than merely potential, does
our conception of it qua cause change in any way? Aristotle
leaves this ambiguous in Metaphysics V.2, but some medieval
philosophers thought it necessary to posit an additional state of
affairs to explain the dynamic aspect of causality, i.e., the fact
that a contingent state of affairs needs to be brought about by some
agent. Thus, if we think of God as the cause of Socrates, there must
be something else, God’s-being-the-cause-of-Socrates (deum esse
causam Sortis), distinct from both God and Socrates, to account
for his existence. This ‘something else’ then becomes not
only what is signified by the proposition ‘God is the cause of
Socrates’ (complexe significabile), but also the proper
object of our knowledge that God is the cause of Socrates. Buridan
replies by arguing that philosophers who think this way do not know
how to interpret human discourse. They take everything too
literally. But we should not be misled by what a proposition literally
says, or seems to say, into thinking that there must be some new kind
of entity corresponding to God’s being the cause of Socrates,
especially since such reifying moves do not help us to understand what
is happening when a cause actually causes (QM V.7-8: 30va-33ra).

The same sensitivity to questions of interpretation is evident in
his treatment of propositions in natural philosophy, where he argues
that we can meaningfully use propositions containing terms such as
‘infinite [infinitum]’ and ‘point
[punctum]’ to express actual states of affairs without
committing ourselves to the existence of infinite magnitudes or
indivisible points. The key is to realize that propositions do not
always wear their meanings on their sleeves. Their component terms can
be differently construed (e.g., categorematically or
syncategorematically), and can even perform different modal functions,
which, depending on how the proposition is read (e.g., in a composite
or divided sense) can change its truth
conditions.^[13]
There will be ambiguities, of course, but Buridan is steadfast in his
assumption that the rational inquirer will always be able to sort them
out, given the right dialectical tools.

4. Logic

Following Aristotle and Porphyry, Buridan’s logic is based on two
distinct, but complementary, conceptions of its purpose: theoretical or
pedagogical (logica docens) and practical (logica
utens).^[14]
The former, he says, is so called because “it teaches
[docet] us how, and from what [materials], arguments should
be constructed, whether those arguments be demonstrative, dialectical,
or of some other kind”. The latter takes its name from the fact
that “it uses [utitur] arguments in order to prove
whether some conclusion is evident, regardless of the subject matter
of the conclusion” (QIP 1: 126-7, ll.176-80). But since the
teaching of logic is ordained to its use, Buridan holds that logic is
ultimately a practical rather than a speculative discipline.

Historians of logic usually classify Buridan among the terminists or
‘moderns’, a diverse group of thirteenth and
fourteenth-century logicians who regarded the semantic properties of
terms (literally, the ‘ends [termini]’, or
subjects and predicates, of propositions) as the primary unit of
logical analysis. As we saw above, in addition to commenting on
Aristotle’s Organon, he wrote a logical compendium, the
Summulae de dialectica, ostensibly as a commentary on Peter
of Spain’s Summulae logicales, an influential terminist
textbook written a century earlier. But Buridan’s Summulae
was essentially a new work, more that ten times longer than the
original and featuring many new and completely rewritten sections. In
it, Buridan leads his students and readers through an orderly
progression of teachings, beginning with propositions (Treatise I),
shifting down to the signification and referential function of their
component terms (II-IV), then back up to terms and propositions
insofar as they figure in more complex patterns of reasoning:
syllogisms (V), topics (VI), fallacies (VII), and finally,
demonstrations (VIII). The work concludes with a kind of exercise book
on paradoxical and otherwise puzzling propositions, showing how they
can be resolved using the techniques of the previous eight
treatises.

No encyclopedia article can do justice to the richness and variety
of Buridan’s logic, but there are several moments from the text that
illustrate how he practiced the dialectical art.

First, Buridan did much to streamline and better articulate the
methods of terminist logic. The most important analytical tool in the
Summulae is the doctrine of suppositio
[supposition], which had been a feature of terminist logic for several
generations by the time Buridan arrived in Paris. Terms were thought
to possess two general semantic properties: signification, or what a
term ‘makes known’ in the mind of the person who sees it
or hears it or conceives of it, whether mediately or immediately
(thus, the written term ‘Socrates’ brings to mind the
concept of Socrates, which in turn signifies the actual person); and
supposition, which refers to the capacity of certain substantive terms
to stand for or ‘pick out’ something in a particular
context, such as in a proposition. Although the analogy is not
perfect, supposition performs many of the same functions as what we
would call the theory of
reference.^[15]
Traditional accounts divided supposition into proper supposition,
where a term is used with its typical or standard meaning, and
improper supposition, where a term is used in some metaphorical or
figurative sense. Most logicians went on to distinguish three kinds of
proper supposition: personal, where a term stands for what it
signifies (e.g., ‘Socrates’ in ‘Socrates is a
man’); material, where it stands for itself (e.g.,
‘man’ in ‘Man has three letters’); and simple,
where it stands for a common nature or concept (e.g.,
‘man’ in ‘Man is a species’). Simple
supposition appears to have been a vestige of early terminist
logic,^[16]
whose realist practitioners needed to distinguish between referring
to a universal thing and referring to a particular thing. But by the
fourteenth century, the whole notion of universals had become more
controversial, and nominalist logicians in particular were not about
to accept any special device for referring to them through common
terms such as ‘man’. So simple supposition was readapted
to model reference to common concepts or intentions. Thus, Ockham
holds that a term exhibits simple supposition when it supposits
“for a concept in the mind [pro conceptu
mentis],” and is not being used
significatively.^[17]
What united Ockham and his terminist predecessors was their
realization that if the proposition ‘Man is a species’ is
to be true, then the term ‘man’ cannot supposit personally
for any of the individual men it ultimately signifies, since it cannot
be said of any of them that he is a species (Socrates is a man, not a
species). Accordingly, the reference of ‘man’ must be to
a common nature or concept.

But Buridan contends that there are only two ways a term can stand
for something in a proposition, personally and materially:

Of the first [section on the divisions of supposition], we
should realize that some people have posited also a third member,
which they call ‘simple supposition’. For they [e.g.,
Peter of Spain] held that universal natures are distinct from the
singulars outside of the soul. And so they said that a term supposits
personally when it supposits for the singulars themselves, that it
supposits simply when it supposits for that material nature, and
materially when it supposits for itself. But I hold that Aristotle
correctly refuted that opinion in the seventh book of the
Metaphysics [VII.3.1038b1-1039a23] and so this kind of
supposition has to be eliminated, at least according to this
interpretation. In another manner, others [e.g., Ockham] call
supposition ‘simple’ when an utterance supposits for the
concept according to which it is imposed and material when it
supposits for itself or another similar to itself. And this can be
permitted, but I do not care [about this usage], for I call both
‘material supposition’. (S 4.3.2: 253)

Buridan sees that it is misleading to assign a special logical sense
to terms being used to refer to themselves or to the concepts they
express, as if this were any different from figurative or metaphorical
usage, since only terms that refer to things existing per se
are being used in their proper sense. Thus, terms can stand either for
the things they ordinarily signify, in which case they supposit
personally, or for something else, in which case they supposit
materially. Material supposition applies whenever a term is used in
some way that departs from the meaning imposed upon it by the
linguistic community:

an utterance does not have any proper import [virtus
propria] in signifying and suppositing, except from ourselves. So
by an agreement of the disputing parties, as in obligational disputes,
we can impose on it a new signification, and not use it according to
its common signification. We can also speak figuratively
[transsumptive] and ironically, according to a different
signification. But we call a locution ‘proper’ when we use
it according to the signification properly and principally given to it,
and we call a locution ‘improper’ when we use it otherwise,
although we legitimately can use it otherwise. So it is absurd to say
that a proposition of an author is false, absolutely speaking, if he
puts it forth incorporating an improper locution, according to which it
is true. Instead, we ought to say that it is true, since it is
enunciated according to the sense in which it is true. (S 4.3.2:
256)

Notice that the default interpretation of a term is its proper
sense, defined as “the signification properly and principally
given to it”. The proper signification of a term must be based on
the fact that “utterances were primarily and principally imposed
to signify so as to stand for their ultimate significata, and
not for themselves” (S 4.3.2:
256);^[18]
that is to say, just as concepts (at least in the first instance)
naturally signify those extra-mental things that just as naturally
give rise to them, so spoken and written terms (at least in the first
instance) are imposed to signify, via their corresponding concepts,
the same ultimate
significata.^[19]
For Buridan, this capacity is natural to us as creatures endowed with
the power of cognition. It is why he insists that determining the
nature of concepts pertains not to logic but to psychology or
metaphysics, speculative sciences whose conclusions cannot be
otherwise (QDI I.3:6, ll.
4-10).^[20]
So even if we say that the proposition, ‘Man is a
species’ is true insofar as it is put forward in the context of
Aristotle’s Categories, it is not literally true, or true
according to “the signification properly and principally given
to it”, because of no per se existing man is it true to
say that he is a species. What happens is that when we work on the
Categories, we follow Aristotle’s lead and depart from
conventional usage in such a way that the term ‘man’
supposits not for individual men but for the universal concept
according to which it was imposed to signify, in which case the
proposition is true because “species and genera are universals
according to predication” (S 4.3.2: 254). So it can be true that
man is a species without it being literally true that man is
a species.

The second way in which Buridan changed the dialectical landscape
was to extend the range of traditional logic. There are numerous
examples of this, not all of which are uncontroversial because it is often
hard to tell what Buridan intended to achieve by a given innovation
(this goes for other medieval logicians as
well).^[21]
But a fairly uncontroversial example can be found in his use of
supposition to examine the structure of certain complex terms that
would remain unanalyzed on the traditional account of syllogistic
inferences. Of particular importance here is the doctrine of
ampliation. Thus, although the syllogism, ‘Nothing dead is an
animal, some man is dead; therefore, some man is not an animal’,
is an acceptable fourth-mode syllogism of the first figure
(Ferio), Buridan denies that the consequence is
“formally valid”. The reason is that in this syllogism,
‘man’ is an ampliative term, and “from an ampliated
nondistributed term the same term does not follow nonampliated”
that is, “in the minor proposition the term ‘man’
was ampliated to past [things], whereas in the conclusion it was not
ampliated,” making the premises true but the conclusion false (S
5.3.2: 326; cf. QAnPr I.14). Similarly, terms referring to the divine
persons sometimes generate counterexamples to the traditionally
accepted modes. Thus, “the following syllogism in
Barbara is invalid: ‘Every God is the son, every divine
Father is God; therefore every divine Father is the Son”, for
the transitivity of identity fails in cases “where the most
simple unity is a trinity of really distinct persons” (S 5.3.2:
327). Buridan also urges the reader to be wary of modal contexts
introduced by verbs of knowing and believing because “the verb
‘know’ ampliates the subject to supposit not only for
present things, but also for future and past ones”. This means
that without suitable qualification, “although I know that every
man is an animal, nevertheless, it does not follow that every man is
known by me to be an animal; for then it would follow that every man,
whether alive or dead or yet to be born, would be known by me to be an
animal, which is false” (S 5.6.8: 348). What is noteworthy in
these and other examples is Buridan’s use of the doctrine of
supposition to extend the range of ‘truth-makers’ for
modal inferences, e.g., in his assumption that “the presence of
a modal copula — any modal copula — in a proposition
ampliates the subject to stand for not only the actual things but also
the possible things that fall under that
term”.^[22]
Because it makes merely possible objects relevant to the evaluation
of modal inferences, ampliation can be seen as a kind of Buridanian
equivalent of possible worlds semantics, though it would be a mistake
to regard it as a remarkable anticipation of that twentieth-century
doctrine. Buridan’s remarks on its theoretical significance are
few,^[23]
and, despite the degree of technical sophistication involved, he
probably did not see it as a radical innovation, but as part of his
ongoing effort to make existing schemes for checking inferences more
practicable.

Third, and finally, Buridan made major contributions to certain
forms of logical inquiry that originated in the medieval period. Most
modern logicians know of his solutions to alethic paradoxes such as the
Liar, which are addressed in the eighth and final chapter of ninth
treatise of the Summulae, which belongs to the medieval
literature of sophismata or
insolubilia.^[24]
The 7th sophism Buridan considers is ‘Every proposition is
false’. The case posits “that all true propositions are
annihilated while the false ones remain [in existence], and then
Socrates propounds only this [proposition]: ‘Every proposition
is false’” (S 9.8, 7th sophism: 965). The question is then
asked whether Socrates’s proposition is true or false. The arguments
on each side of the question illustrate the difficulties one faces if
‘true’ and ‘false’ are interpreted
strictly. The argument that it is false assumes that “it is
impossible for the same proposition to be true and false when
propounded in the same language and understood in the same way by
everyone hearing it”, and proceeds to argue that the sophism is
false because any proposition which entails its own contradictory is
impossible, and therefore false. The opposite side begins by focusing
on the logical form of the sophism as a universal affirmative that has
no counter-instance in the case at hand, which stated that all true
propositions have been annihilated with only the false ones
remaining. Second, the sophism must be true because the subject and
predicate terms supposit for the same things: if every proposition is
false, then each and every propositional significate of the term
‘every proposition’ must be false, as it indeed is,
according to the case. Finally, the sophism must be true because
“it signifies only that every proposition is false; and this is
how things are [ita est]”, according to the case (S
9.8, 7th sophism: 965).

Buridan writes as if this particular sophism enjoyed some notoriety
among logic teachers at Paris, although all but one of the alternative
solutions he mentions were discussed and criticized from the very
beginning of the insolubilia literature. These involve various
ad hoc proposals that either build new assumptions into the
case or else make up new rules about how the terms of the sophism are
to be
interpreted.^[25]
Into the first category falls a solution known as the
‘transcasus’, which involves the bizarre
suggestion that the time Socrates utters his proposition and the time
referred to by the verb of the proposition are not the same. This
would allow us to say that if there are no true propositions during
the first hour of a certain day, Socrates could utter his proposition
at the end of this hour and it would be true, where he is understood
as referring “not to the time at which he speaks but to the time
of that first hour”. But this is of no help if we stick to the
case and assume that the times are the same. Alternatively, in a
solution advocated by the ‘restringentes
[restrictors]’ — so-called because they avoided self-reference
by restricting what a term can supposit for — we could make the
proposition non-reflexive by stipulating that “terms that are
apt to supposit for propositions are not put in propositions to
supposit for the propositions in which they are put, but for
others”. But Buridan rightly rejects this second strategy as
failing to take seriously our conventional understanding of terms, for
when one uses the term ‘proposition’, he says, “one
understands indifferently all propositions, indeed, present, past, and
future ones, his own as well as those of another person”. A
moment’s reflection should make it obvious that “this solution
is worth nothing: for what one understands, of that he can speak
[quod aliquis intelligit, de hoc potest loqui]” (S 9.8,
7th sophism:
966).^[26]

Buridan’s quick answer to the sophism is that Socrates’s proposition
is false in the case at hand. But before moving on to his final answer,
he first discusses a solution described as being held by some people,
including
himself.^[27]
This is that there is another condition, in addition to the
requirement that its terms stand for the same thing or things, which a
proposition must meet if it is to be true. A proposition must also
signify or assert itself to be true (S 9.8, 7th sophism:
967).^[28]
In her detailed analysis of this sophism,
Fabienne Pironet has shown that the text in which Buridan defends this
earlier view is his question commentary on Aristotle’s Posterior
Analytics, where it is expressed in terms of the traditional
formula that “howsoever [a proposition] signifies, so it is
[qualitercumque significat, ita est]” (QAnPo
I.10).^[29]
Now Buridan holds that all propositions satisfy this condition
trivially: “every proposition by its form signifies or asserts
itself to be true” (S 9.8, 7th sophism: 967). The problem with
self-referential paradoxes is that they also seem to signify that they
are false. Thus, although the proposition ‘I say what is false
[ego dico falsum]’ “signifies itself to be true
in some fashion, nevertheless this is not so entirely, or howsoever it
signifies [licet aliqualiter sic significat, non tamen totaliter
vel qualitercumque ita est]. Therefore it is false” (QAnPo
I.10).

Unfortunately, this looks no less ad hoc than the
transcasus and restriction solutions he has just criticized.
Why shouldn’t other propositions, besides the paradoxical ones, be
able to signify that they are false? Buridan does not say in his
commentary on the Posterior Analytics, and in the
Summulae he rejects his earlier view for the rather different
reason that it is false “that every proposition signifies or
asserts itself to be true” (S 9.8, 7th sophism: 968). His
argument is not exactly clear, but the problem appears to be semantic:
he cannot find an interpretation of the phrase ‘itself to be
true [se esse veram]’ in the supplementary condition
that will permit it to function as a general principle. Consider the
proposition ‘A man is an animal [homo est
animal]’. If we understand it materially, i.e., as standing
for a proposition, then it will signify ‘The proposition
“A man is an animal” is true’, which is false
because it refers to second intentions (concepts or signs by means of
which we conceive of other concepts or signs as such), and the
original proposition refers to things (human beings and animals), not
concepts. But what if we say that a proposition signifies itself to be
true if it is taken significatively for the things or first
intentions, rather than materially? This will not work either, argues
Buridan, because then the affirmative proposition ‘A man is a
donkey [homo est asinus]’ would signify that a man is a
donkey, which is false because the subject term ‘man’ does
not supposit for anything (no human beings are
donkeys).^[30]
Accordingly, we cannot base our solution to self-referential
paradoxes on the idea that every proposition signifies or asserts
itself to be
true.^[31]

The solution Buridan finally settles on receives the somewhat tepid
endorsement of being “closer to the truth” than the
previous solution — a reflection, perhaps, of his awareness of the
imperfectability of any formal system that tries to stick close to the
facts of human language. Here, the idea that a proposition formally
signifies itself to be true is replaced by the notion of implication
from the doctrine of consequences. “Every proposition,” he
says, “virtually implies another proposition in which the
predicate ‘true’ is affirmed of the subject that supposits
for [the original proposition]” (S 9.8, 7th sophism:
969).^[32]
Unlike the old solution, in which the second proposition is signified
by the first and hence part of its meaning, the new solution assumes
only that the second proposition follows logically from the first, so
that its meaning can be expounded separately. In this way, for the
truth of any proposition P, it is required not only (1) that the
subject and predicate terms of P stand for the same thing or
things,^[33]
but also (2) that P implies another proposition,
‘P is true’, which must also be true. Otherwise,
we would have a true antecedent and a false consequent, violating
Buridan’s fifth theorem regarding assertoric consequences, which
states, “it is impossible for what is false to follow from what
is true [impossibile est ex veris sequi falsum]” (TC
I.8: 34, l. 97). Applying this to the 7th sophism, the constituent
terms in the proposition uttered by Socrates — ‘Every
proposition’ and ‘false’ — stand for the same
things, since in the posited case, “all true propositions are
annihilated and the false ones remain, and then Socrates propounds
only this: ‘Every proposition is false’”. So the
first condition is satisfied. But the implied proposition,
‘P is true’ (where P is the name of
‘Every proposition is false’), is false because its
constituent terms, ‘Every proposition is false’ and
‘true’, do not stand for the same thing, since ex
hypothesi, P stands for the antecedent proposition
‘Every proposition is false’, not for things that are
true. But this gives us a true antecedent and a false consequent, and
so the consequence does not hold. Therefore, the sophism is false.

5. Metaphysics

Buridan’s metaphysics is thoroughly informed by his logic. He tries
wherever possible to apply the Summulae‘s analytical
techniques to solve problems in speculative philosophy. His approach
is critical in the sense that he tends to view traditional problems in
metaphysics as based on confusions of logic or language. For the same
reason, his solutions are not original in the modern sense of being
without precedent, although they have few equals in terms of their
elegance and economy of expression. Where philosophical argumentation
is concerned, Buridan is a master craftsman.

Like most arts masters in fourteenth-century Paris, Buridan is careful
to dissociate the metaphysical questions he asks as a philosopher from
similar questions that might be asked by a theologian. Jurisdictional
disputes forced Parisian arts masters to be quite clear about how they
were approaching a
problem,^[34]
although what we now identify as medieval philosophy was practiced by
both sides. As far as Buridan is concerned, much of the confusion over
the proper domains of metaphysics and theology stems from Aristotle
himself, who identifies three kinds of speculative science: physics,
mathematics, and
theology.^[35]
In his question commentary on the Metaphysics, he provides
the standard medieval interpretation of this passage, reading
‘theology’ as ‘metaphysics’ and
differentiating the three sciences in terms of how they treat their
respective subjects: whereas the natural philosopher considers things
insofar as they are qualified by motion, and the mathematician insofar
as they are quantified by number, the metaphysician considers them
only insofar as they pertain to the “concept of being [ad
rationem essendi]” (QM VI.2:
34ra).^[36]
For the difference between metaphysics and theology, however, we need
to go to the very beginning of the commentary, where he offers the
following gloss of Aristotle’s remarks:

It should also be noted that [when we ask whether
metaphysics is the same as wisdom,] we are not comparing metaphysics to
theology, which proceeds from beliefs that are not known, because
although these beliefs are not known per se and most evident,
we hold without doubt that theology is the more principal discipline
and that it is wisdom most properly speaking. In this question,
however, we are merely asking about intellectual habits based on human
reason, [i.e.,] those discovered by the process of reasoning, which are
deduced from what is evident to us. For it is in this sense that
Aristotle calls metaphysics ‘theology’ and ‘the
divine science’. Accordingly, metaphysics differs from theology
in the fact that although each considers God and those things that
pertain to divinity, metaphysics only considers them as regards what
can be proved and implied, or inductively inferred, by demonstrative
reason. But theology has for its principles articles [of faith], which
are believed quite apart from their evidentness, and further, considers
whatever can be deduced from articles of this kind. (QM I.2:
4ra-rb)

The difference is that theologians take their principles
(‘principia’ = (lit.) ‘starting
points’) from articles of faith rather than, like the
philosophers, from what is evident to the senses and intellect. So it
is possible for the same question — e.g., about the limits of divine
omnipotence — to be raised in both domains, though it will have a
more creaturely orientation for the
philosopher.^[37]
Buridan concedes de jure place of privilege to theology
because of its subject matter, but treats philosophy and theology as
de facto equivalent in the speculative realm. Metaphysics, or
philosophical wisdom, cannot be ordained by theology because its
methods, which are rooted in its principles, are different. Philosophy
is accordingly not inferior to theology, just
different.^[38]

With regard to the problem of
universals,^[39]
Buridan does not so much create a new theory as show how our
theoretical commitments can be expressed with a minimum of ambiguity
and fuss. Like Ockham, he is a nominalist, although this term must be
used with caution in later medieval philosophy because of the modern
tendency to identify it with the denial of real universals. It must be
remembered that most fourteenth-century philosophers were nominalists
in this sense because they associated the contrary doctrine with
Plato, with whom they were familiar only secondarily as one of the
authors whose views are thoroughly discredited by Aristotle in Book I
of the
Metaphysics.^[40]
But medieval nominalism involved much more than rejecting Platonic
universals. Its history can be traced to twelfth-century disputes over
the reading of sacred texts, in which the techniques of logicians such
as Abelard were pitted against those of grammarians such as Peter
Helias.^[41]
As these disputes evolved and matured, nominalism was gradually
absorbed into the teaching of philosophers working in the faculty of
arts, so that by Buridan’s time, it is better to think of nominalism
as a practice, or way of doing philosophy, rather than as a piece of
doctrine.

When Buridan considers questions such as “whether universals
actually exist outside the soul” (TDUI: 137), his remarks are
almost always aimed at clarifying the meaning of the term
‘universal’ with respect to other terms such as
‘individual’, ‘particular’, and
‘singular’. His rejection of realism is expressed in the
claim that universal terms have no ultimate significate, i.e., nothing
outside the soul they can ‘make known’ as
such.^[42]
Hence, an account is needed of what such terms mean. Here, it is
almost as if Buridan thinks there is something ill-formed about
propositions where the term ‘universal’ occurs in the
subject position, for when confronted with them his first move is
always to tell us how the term ‘universal’ is to be
understood (QIP 3: 136, ll.
477-488).^[43]
He argues further that the primary
signification of ‘universal’ is ‘predicable of
many’, which makes it a term of second intention, or a term of
terms, since only terms are predicable (QIP 3: 135-136; 4: 139; TDUI:
148).^[44]
The second-intentional status of the term ‘universal’ is
also evident in propositions, where it does not signify a
‘what’ but a ‘how’, i.e., how we conceive of
something — in this case how the term so designated is
“indifferent to many supposits,” or individuals
(TDUI:59).^[45]
As we saw above, logic is the study of terms such as
‘proposition’ taken materially, signifying actual tokens
of the type (QDI I.1: 6). Moving from propositions to arguments,
Buridan insists that terms in the premises and conclusions of
demonstrative arguments must be taken as standing materially, i.e.,
for themselves in the particular discourse conditions which surround
them, rather than personally, for their extra-mental significates (QIP
1: 128, ll. 223-237). Likewise, the proximate object of scientific
knowledge is the actual demonstrated or demonstrable conclusion rather
than the state of affairs it signifies, although Buridan is willing to
concede that “the terms of those demonstrable conclusions, or
even the things signified by those conclusions” might be
considered “remote”, or secondary, objects of knowledge
(QIP 1: 127, l.
208-209).^[46]
Careful and systematic analysis is the best antidote for metaphysical
perplexity because the trouble usually begins with untutored persons
who use some word or concept without knowing what it means.

It should be noted that Buridan’s methods do not always produce
parsimonious results. Like Ockham, he has only substances and qualities
in his basic ontology, but he is much more willing than Ockham to
expand this in the direction of modes or ways of being when confronted
with recalcitrant phenomena. Thus, he argues that we must treat the
question of how something is as distinct from what it
is if we are to have a coherent understanding of motion, especially
since the Ockhamist view is forced to posit an infinite succession of
spatial qualities (QM V.9: 32va; QP II.3:1ra-rb; QP IV.11:
77va-78rb).^[47]
Likewise, in a famous passage, Buridan is driven by his own
experience to reject Ockham’s explanation of condensation and
rarefaction as kinds of locomotion. Why, he asks, does he find himself
unable to compress further the air in a bellows which has been stopped
up at one end? Not because of its matter, since more matter could
exist in a much smaller space; nor because of the substantial form of
the air, which would fill a much smaller space once it has been
cooled; nor even because of the heat it possesses, since more heat
could exist in a much smaller space, such as at the end of a red-hot
poker. No, the air must have a distinct quantitative form or magnitude
preventing it from being moved. Against those who would do away with
this distinction, Buridan argues that “a magnitude of this sort
has not been posited in vain, for we have been compelled to posit it
by arguments that make it seem as useful or even more useful to
natural philosophy than [the qualities of] whiteness or
blackness” (QP.8:
11vb).^[48]

6. Natural Philosophy

Medieval natural philosophy included both the rich commentary
tradition on Aristotle’s Physics, as well as treatises and
commentaries on Aristotle’s other writings about the natural world:
On the Heavens, On Generation and Corruption, De
anima, the short treatises on animate powers known as the
‘Parva Naturalia’, and the works on the history,
parts, and generation of animals. Buridan wrote commentaries on nearly
all of these texts. Like his contemporaries, he understood the
speculative sub-disciplines of physics as an orderly progression of
teachings. Thus, demonstration in psychology was thought to borrow its
principles or starting points from physics, the higher science to
which it is subordinated, with its conclusions in turn supplying
principles for demonstrations in the more specialized studies of
sensation and animal locomotion. The ordering metaphor is never far
from Buridan’s mind. He remarks to readers of his commentary on
Aristotle’s De motibus animalium that in this book, “we
descend to the different species of motion in particular, e.g., to the
fact that some animals fly, others swim, and so on” (DMA I:
535)

Besides logic, natural philosophy is the other field in which Buridan
has enjoyed some recognition. This is largely due to the efforts of
the pioneering historians of science Pierre Duhem and Anneliese Maier,
who saw that Buridan played a key role in the demise of the
Aristotelian view of the
cosmos.^[49]
Buridan’s major contribution here was to develop and popularize the
theory of impetus, or impressed force, to explain projectile
motion. Rejecting the discredited Aristotelian idea of antiperistasis,
according to which the tendency of a thrown projectile to continue
moving is due to a proximate but external moving cause (such as the
air surrounding
it),^[50]
he argues that only an internal motive force, transmitted from the
mover to the projectile, could explain its continued motion. The
theory of impetus probably did not originate with
Buridan,^[51]
but his account appears to be unique in that he entertains the
possibility that it might not be self-dissipating: “after
leaving the arm of the thrower, the projectile would be moved by an
impetus given to it by the thrower,” he says, “and would
continue to be moved as long as the impetus remained stronger than the
resistance, and would be of infinite duration were it not diminished
and corrupted by a contrary force resisting it or by something
inclining it to a contrary motion” (QM XII.9: 73ra). He also
contends that impetus is a variable quality whose force is determined
by the speed and quantity of the matter in the subject, so that the
acceleration of a falling body can be understood in terms of its
gradual accumulation of units of impetus. But despite its
revolutionary implications, Buridan did not use the concept of impetus
to transform the science of mechanics. He was not, as Duhem argued, a
forerunner of Galileo. He remained unapologetically Aristotelian in
too many other respects, continuing to hold that motion and rest are
contrary states of bodies and that the world is finite in
extent. Buridan seems to have been a philosopher who, though well
aware of the shortcomings of the Aristotelian natural philosophy,
tried to reshape as much of it as he could in the face of a rapidly
mechanizing
worldview.^[52]
His revolution was in the details. The big, decisive break was left
to his successors.

Buridan’s account of motion is in keeping with his approach to natural
science, which is empirical in the sense that it emphasizes the
evidentness of appearances, the reliability of a posteriori modes of
reasoning, and the application of naturalistic tropes or models of
explanation (such as the concept of impetus) to a variety of
phenomena. He is inclined to dismiss purely theological assumptions
as irrelevant to the practice of philosophy, as we see in the
following tongue-in-cheek remark: “one might assume that there
are many more separate substances than there are celestial spheres and
celestial motions, viz., great legions of angels [magnae legiones
angelorum], but this cannot be proved by demonstrative arguments
originating from sense perception” (QM II.9:
73ra).^[53]
But there are some theological considerations that must be taken
seriously. He concedes that divine omnipotence is such that it is
always possible for God to deceive us in ways we could never detect,
although this is tempered by his confidence, for which he cites
empirical evidence, that our ordinary powers of perception and
inductive inference are sufficiently reliable to make “the
comprehension of truth with certitude possible for us” (QM II.1:
9ra). He has little patience for skeptical arguments questioning the
possibility of scientific knowledge, such as those he believed to have
been advanced by Nicholas of Autrecourt, arguing that it is absurd to
demand that all knowledge be demonstrable by reduction to the
principle of non-contradiction. Natural science is about what happens
for the most part, i.e., assuming the common course of nature. For the
same reason, explanatory models in one special science can be usually
applied to others in a way that enhances our understanding of the
phenomena. Thus, the concept of impetus recurs in Buridan’s psychology
to explain the difference between occurrent and dispositional
thinking, as well as in his ethics, to account for the relative ease
with which virtuous persons are able to do the right thing (they have
acquired, or cultivated within themselves, an impetus to act
virtuously).

In psychology, the study of moving beings qua animate,
Buridan changed the Aristotelian paradigm in important ways. In
contrast with Thomas Aquinas, who wanted to attribute metaphysically
more robust qualities, such as per se subsistence, to the
human soul, Buridan does not think that psychology is in a position to
reveal anything about the inherent nature of its subject, and so he refuses
to speculate about it. He sees the science of psychology as concerned
not with some quidditative concept of the soul arrived at by a
priori reasoning, but with specifying the relation between animate
qualities and the soul as their proper subject: “the natural
philosopher only studies substances in relation to their motion and
operations. And since natural forms require for their operations a
determinate matter made suitable for them by qualitative and
quantitative dispositions, natural scientists must define forms through
their proper matter. Therefore, in its natural definition, the soul
must be defined by means of a physical, organic body” (QDA II.3:
34). This led to an even more attenuated conception of the soul in the
De anima commentaries of Buridan’s Parisian successors, Nicole
Oresme and Peter of Ailly, for whom the soul functions as a kind of
placeholder whose nature is not even relevant to psychology.
Consideration of the soul’s ultimate nature migrated to the
faculty of theology, where it was considered along with the same
Augustinian dreaming arguments that undoubtedly influenced
Descartes.^[54]

Buridan’s resolute naturalism is even more evident in his account of
human knowledge. Here he is a representationalist, but mainly because
he can find no evidence to support the contrary view, defended by both
Duns Scotus and William of Ockham, that humans possess an
intuitive mode of knowing that gives us a direct and unmediated
awareness of the existence of some
subject.^[55]
Buridan holds that cognition can occur only when the intellect
apprehends an object by means of a particular species or concept
representing it. How we use the concept in our act of apprehension
determines whether we cognize singularly or universally: singularly,
if its object appears to us “in the manner of something existing
in the presence of the person cognizing it” universally, if we
focus on certain features of the concept to the exclusion of others,
such as when we cognize “all human beings indifferently”
via the humanity that is in the concept of Socrates (QDA III.8: 79-80;
QP I.7: 8va). How do we know whether our concept of Socrates is really
a concept of Socrates? As noted above, Buridan tends to regard
skeptical worries as tiresome and pedantic. Like most pre-Cartesian
epistemologists (if it makes sense to use that term before Descartes),
he is more interested in explaining the process by which we come to
have knowledge than he is in justifying knowledge claims.

7. Ethics

Buridan’s commentary on Aristotle’s Nicomachean Ethics is
one of his most influential works, though it is today perhaps the least
studied. It contains significant discussions of the structure of the
will and its relation to the intellect, the nature of human freedom,
the phenomenon of akrasia or weakness of will, practical
reason, and the unity of the
virtues.^[56]

In moral psychology, Buridan appears to effect a compromise between
two rival views on the relation between the will and the intellect: the
intellectualist or naturalist tradition associated with Aristotle and
Thomas Aquinas, according to which the will is always subordinate to
the intellect, and the voluntarist tradition of Augustine and
Franciscan thinkers such as Duns Scotus and William of Ockham, which
held that the will is sometimes capable of autonomous activity.
Buridan’s apparent compromise is to argue (with the intellectualists)
that human happiness ultimately consists in an intellectual act,
“the perfect apprehension of God”, rather than in a
volitional act such as perfectly willing or perfectly loving God (QNE
X.5: 213rb), although he emphasizes (with the voluntarists) the role of
the will as a self-determining power in achieving that end. The
compromise turns on Buridan’s innovative conception of free choice,
which develops Albert the Great’s notion that certainty admits of
degrees.^[57]
The idea is that even if the will lacks
the power to choose evil as such, it is still able to defer its choice
and do nothing if the goodness of one of the alternatives presented to
it is unclear or uncertain. Of course, given our poor epistemic
position in this life, it almost always has this power because it
is almost always possible in practice to doubt the goodness of a
proposed course of action. The compromise is only apparent, however,
because it turns out that the will’s act of deferment is possible only
if “the intellect would judge it to be good to consider the
matter further” (QNE III.5:
44va).^[58]
This claim, together with his assumptions that the will can only
choose non-optimally through ignorance or impediment (QNE III.3-5; 9),
places deferment squarely under the jurisdiction of the intellect,
which must weigh the relative goodness of different possible courses
of action, including deferment. It is not the case that the will can
choose to defer regardless of what the intellect decides, or that the
will can choose to defer even if the intellect has judged deferment to
be less good than some other course of action. Accordingly, if this is
a compromise between the intellectualists and the voluntarists, it is
a disingenuous one. It is more likely that Buridan simply appropriated
voluntarist terminology to express what is otherwise a
straightforwardly intellectualist account of the will, perhaps to
dispel the cloud of heterodoxy which had surrounded intellectualist
moral psychology since the Condemnation of
1277.^[59]

It is also in Buridan’s moral psychology that we find the most
plausible explanation of the example that has come down to us known as
‘Buridan’s Ass’, in which a donkey starves to death because
it has no reason to choose between two equidistant and equally tempting
piles of hay. This particular example is nowhere to be found in
Buridan’s writings, although there are versions of it going back at
least to Aristotle (see De Caelo
295b32).^[60]
The best explanation of its association with Buridan is that it
originated as a parody of his account of free choice by later critics,
who found absurd the idea that the will’s freedom could consist in
inaction, i.e., in its ability to defer or ‘send back’ for
further consideration any practical judgment that is not absolutely
certain.

Bibliography

Early Printed Editions

Buridan, John: 1509, Subtilissimae Quaestiones super octo
Physicorum libros Aristotelis, Paris. Rpr. 1964, as Kommentar
zur Aristotelischen Physik, Minerva, Frankfurt a. M. [QM]
Buridan, John: 1513, Quaestiones super decem libros Ethicorum
Aristotelis ad Nicomachum, Paris. Rpr. 1968, as Super decem
libros Ethicorum, Minerva, Frankfurt a. M. [QNE]
Buridan, John: 1588 (actually 1518), In Metaphysicen
Aristotelis Questiones argutissimae, Paris. Rpr. 1964, as
Kommentar zur Aristotelischen Metaphysik, Minerva, Frankfurt
a. M. [QP]

Modern Editions

Bos, E. P. (ed.): 1994, Johannes Buridanus, Summulae: In
Praedicamenta, Artistarium 10-3, Ingenium, Nijmegen.
Dekker, Dirk-Jan: 2004, “John Buridan’s Treatise, De
dependentiis, diversitatibus, et convenientiis,”
Vivarium 42.1: 109-149.
Hubien, Hubert (ed.): 1976, Iohannis Buridani Tractatus de
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Translations

Hughes, G. E. (ed. & tr.): 1982, John Buridan on
Self-Reference: Chapter Eight of Buridan’s
‘Sophismata’, An Edition and Translation with an
Introduction and Philosophical Commentary, Cambridge University Press,
Cambridge-London-New York. (Cambridge also published a paperbound
edition of this book, though without the facing Latin text and hence
with different pagination. It also has a slightly different subtitle,
“Chapter Eight of Buridan’s ‘Sophismata’, translated
with an Introduction and a philosophical Commentary”, which is
useful for identifying it in online searches.)
Kilcullen, John (ed. & tr.): 2001, “Jean Buridan, Questions
on Book X of the Ethics,” in The Cambridge Translations of
Medieval Philosophical Texts. Volume II: Ethics and Political
Philosophy, ed. Arthur Stephen McGrade, John Kilcullen, and
Matthew Kempshall, Cambridge University Press, Cambridge-New York.
Pp. 498-586.
King, Peter (tr.): 1985, John Buridan’s Logic: The
Treatise on Supposition; The Treatise on Consequences, Translation from
the Latin with a Philosophical Introduction, Reidel,
Dordrecht-Boston-Lancaster.
Klima, Gyula (tr.): 2001, John Buridan: ‘Summulae de
Dialectica’, Yale Library of Medieval Philosophy, Yale
University Press, New Haven-London. [S]

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