William of Ockham (Stanford Encyclopedia of Philosophy)

William of Ockham
(Stanford Encyclopedia of Philosophy)

First published Fri Aug 16, 2002; substantive revision Sun Jul 9, 2006

William of Ockham (c. 1287-1347) is, along with Thomas Aquinas and
John Duns Scotus, among the most prominent figures in the history of
philosophy during the High Middle Ages. He is probably best known
today for his espousal of metaphysical nominalism; indeed, the
methodological principle known as “Ockham’s Razor” is
named after him. But Ockham held important, often influential views
not only in metaphysics but also in all other major areas of medieval
philosophy—logic, physics or natural philosophy, theory of
knowledge, ethics, and political philosophy—as well as in

1. Life

Ockham led an unusually eventful life for a philosopher. As with so
many medieval figures who were not prominent when they were born, we
know next to nothing about the circumstances of Ockham’s birth and
early years, and have to estimate dates by extrapolating from known
dates of events later in his

Ockham’s life may be divided into three main periods.

1.1 England (c. 1287-1324)

Ockham was born, probably in late 1287 or early 1288, in the village
of Ockham (= Oak Hamlet) in Surrey, a little to the southwest of

He probably learned basic Latin at a village
school in Ockham or nearby, but this is not
At an early age, somewhere between seven and thirteen, Ockham was
“given” to the Franciscan order (the so called
There was no Franciscan house (called a “convent”) in the
tiny village of Ockham itself; the nearest one was in London, a day’s
ride to the northeast. It was there that Ockham was sent.

As an educational institution, even for higher education, London
Greyfriars was a distinguished place; at the time, it was second only
to the full-fledged Universities of Paris and Oxford. At Greyfriars,
Ockham probably got most of his “grade school” education,
and then went on to what we might think of as “high
school” education in basic logic and “science”
(natural philosophy), beginning around the age of fourteen.

Around 1310, when he was about 23, Ockham began his theological
training. It is not certain where this training occurred. It could well
have been at the London Convent, or it could have been at Oxford, where
there was another Franciscan convent associated with the university. In
any event, Ockham was at Oxford studying theology by at least the year
1318-19, and probably the previous year as well, when (in 1317) he
began a required two-year cycle of lectures commenting on Peter
Lombard’s Sentences, the standard theological textbook of the
day. Then, probably in 1321, Ockham returned to London Greyfriars,
where he remained. Although he had taken the initial steps in the
theology program at Oxford (hence his occasional nickname, the
Venerabilis Inceptor, “Venerable Beginner”),
Ockham did not complete the program there, and never became a fully
qualified “master” of theology at Oxford. Nevertheless,
London Greyfriars was an intellectually lively place, and Ockham was by
no means isolated from the heat of academic controversy. Among his
“housemates” were two other important Franciscan thinkers
of the day, Walter Chatton and Adam Wodeham, both sharp critics of
Ockham’s views. It was in this context that Ockham wrote many of his
most important philosophical and theological works.

In 1323 Ockham was called before the Franciscan province’s chapter
meeting, held that year in Bristol, to defend his views, which were
regarded with suspicion by some of his confreres. About the same time,
someone—it is not clear who—went from England to the Papal
court at Avignon and charged Ockham with teaching

As a result, a commission of theologians was set up to study the
case. Ockham was called to Avignon in May, 1324, to answer the
charges. He never went back to England.

1.2 Avignon (1324-28)

While in Avignon, Ockham stayed at the Franciscan convent there. It
has sometimes been suggested that he was effectively under
“house arrest,” but this seems an exaggeration. On the
contrary, he appears to have been free to do more or less as he
pleased, although of course he did have to be “on hand” in
case the investigating commission wanted to question him about his
writings. The investigation must not have demanded much of Ockham’s
own time, since he was able to work on a number of other projects
while he was in Avignon, including finishing his last major
theological work, the Quodlibets. It should be pointed out
that, although there were some stern pronouncements that came out of
the investigation of Ockham, his views were never officially condemned
as heretical.

In 1327, Michael of Cesena, the Franciscan “Minister
General” (the chief administrative officer of the order) likewise
came to Avignon, in his case because of an emerging controversy between
the Franciscans and the current Pope, John XXII, over the idea of
“Apostolic poverty,” the view that Jesus and the Apostles
owned no property at all of their own but, like the mendicant
Franciscans, went around begging and living off the generosity of
others. The Franciscans held this view, and maintained that their own
practices were a special form of “imitation of Christ.”
Pope John XXII rejected the doctrine, which is why Michael of Cesena
was in Avignon.

Things came to a real crisis in 1328, when Michael and the Pope had
a serious confrontation over the matter. As a result, Michael asked
Ockham to study the question from the point of view of previous papal
statements and John’s own previous writings on the subject. When he did
so, Ockham came to the conclusion, apparently somewhat to his own
surprise, that John’s view was not only wrong but outright heretical.
Furthermore, the heresy was not just an honest mistake; it was
stubbornly heretical, a view John maintained even after he
had been shown it was wrong
. As a result, Ockham argued, Pope John
was not just teaching heresy, but was a heretic himself in the
strongest possible sense, and had therefore effectively abdicated his
papacy. In short, Pope John XXII was no pope at all!

Clearly, things had become intolerable for Ockham in Avignon.

1.3 Munich (1328/29-47)

Under cover of darkness the night of May 26, 1328, Michael of
Cesena, Ockham, and a few other sympathetic Franciscans fled Avignon
and went into exile. They initially went to Italy, where Louis (Ludwig)
of Bavaria, the Holy Roman Emperor, was in Pisa at the time, along with
his court and retinue. The Holy Roman Emperor was engaged in a
political dispute with the Papacy, and Ockham’s group found refuge
under his protection. On June 6, 1328, Ockham was officially
excommunicated for leaving Avignon without
Around 1329, Louis returned to Munich, together with Michael, Ockham
and the rest of their fugitive band. Ockham stayed there, or at any
rate in areas under Imperial control, until his death. During this
time, Ockham wrote exclusively on political
He died on the night of April 9/10,
1347, at roughly the age of

2. Writings

Ockham’s writings are conventionally divided into two groups: the so
called “academic” writings and the “political”
ones. By and large, the former were written or at least begun while
Ockham was still in England, while the latter were written toward the
end of Ockham’s Avignon period and later, in
With the exception of his Dialogue, a huge political work,
all are now available in modern critical editions, and many are now
translated into English, in whole or in

The academic writings are in turn divided into two groups: the
“theological” works and the “philosophical”
ones, although both groups are essential for any study of Ockham’s

Among Ockham’s most important writings are:

  • Academic Writings
    • Theological Works
      • Commentary on the Sentences of Peter Lombard (1317-18).
        Book I survives in an ordinatio or scriptum—a
        revised and corrected version, approved by the author himself for
        distribution. Books II-IV survive only as a reportatio—a
        transcript of the actually delivered lectures, taken down by a
        “reporter,” without benefit of later revisions or
        corrections by the author.
      • Seven Quodlibets (based on London disputations held in
        1322-24, but revised and edited in Avignon 1324-25).
    • Philosophical Works
      • Logical Writings
        • Expositions of Porphyry’s Isagoge and of
          Aristotle’s Categories, On Interpretation, and Sophistic
        • Summa of Logic (c. 1323). A large, independent and
          systematic treatment of logic and semantics.
        • Treatise on Predestination and God’s Foreknowledge with Respect
          to Future Contingents
      • Writings on Natural Philosophy
        • Exposition of Aristotle’s Physics (1322-24). A detailed,
          close commentary. Incomplete.
        • Questions on Aristotle’s Books of the Physics (before
          1324). Not strictly a commentary, this work nevertheless discusses a
          long series of questions arising out of Aristotle’s
  • Political Writings
    • Eight Questions on the Power of the Pope (1340-41).
    • The Work of Ninety Days (1332-34).
    • Letter to the Friars Minor (1334).
    • Short Discourse (1341-42).
    • Dialogue (c. 1334-46).

Several lesser items are omitted from the above list.

3. Logic and Semantics

Ockham is rightly regarded as one of the most significant logicians
of the Middle Ages. Nevertheless, his originality and influence should
not be exaggerated. For all his deserved reputation, his logical views
are sometimes completely
and occasionally very

Logic, for Ockham, is crucial to the advancement of knowledge. In
the “Prefatory Letter” to his Summa of Logic, for example, he
praises it in striking language:

For logic is the most useful tool of all the arts. Without
it no science can be fully known. It is not worn out by repeated use,
after the manner of material tools, but rather admits of continual
growth through the diligent exercise of any other science. For just as
a mechanic who lacks a complete knowledge of his tool gains a fuller
[knowledge] by using it, so one who is educated in the firm principles
of logic, while he painstakingly devotes his labor to the other
sciences, acquires at the same time a greater skill at this

Ockham’s main logical writings consist of a series of commentaries
(or “expositions”) on Aristotle’s and Porphyry’s own
logical works, plus his own Summa of Logic, his major work in
the field. His Treatise on Predestination contains an
influential theory on the logic of future contingent propositions, and
other works as well include occasional discussions of logical topics,
notably his Quodlibets.

3.1 The Summa of Logic

Ockham’s Summa of Logic is divided into three parts, with
the third part subdivided into four subparts. Part I divides language,
in accordance with Aristotle’s On Interpretation (1,
16a3-8, as influenced by Boethius’s interpretation), into
written, spoken and mental language, with the written kind dependent on
the spoken, and the spoken on mental language. Mental language, the
language of thought, is thus the most primitive and basic level of
language. Part I goes on to lay out a fairly detailed theory of terms,
including the distinctions between (a) categorematic and
syncategorematic terms, (b) abstract and concrete terms, and (c)
absolute and connotative terms. Part I then concludes with a discussion
of the five “predicables” from Porphyry’s Isagoge

and of each of Aristotle’s categories.

While Part I is about terms, Part II is about
“propositions,” which are made up of terms. Part II gives a
systematic and nuanced theory of truth conditions for the four
traditional kinds of assertoric categorical propositions on the
“Square of Opposition,” and then goes on to tensed, modal
and more complicated categorical propositions, as well as a variety of
“hypothetical” (molecular[13])
propositions. The
vehicle for this account of truth conditions is the semantic theory of
“supposition,” which will be treated below.

If Part I is about terms and Part II about propositions made up of
terms, Part III is about arguments, which are in turn made up of
propositions made up of terms. As mentioned, Part III is divided into
four subparts. Part III.1 treats syllogisms, and includes a
comprehensive theory of modal

Part III.2 concerns demonstrative syllogisms in particular. Part
III.3 is in effect Ockham’s theory of consequence, although it also
includes discussions of semantic paradoxes like the Liar (the so
called insolubilia) and of the still little-understood
disputation form known as “obligation.” Part III.4 is a
discussion of fallacies.

Thus, while the Summa of Logic is not in any sense a
“commentary” on Aristotle’s logical writings, it
nevertheless covers all the traditional ground in the traditional
order: Porphyry’s Isagoge and Aristotle’s Categories

in Part I, On Interpretation in Part II, Prior
in Part III.1, Posterior Analytics in Part
III.2, Topics (and much else) in Part III.3, and finally
Sophistic Refutations in Part III.4.

3.2 Signification, Connotation, Supposition

Part I of the Summa of Logic also introduces a number of
semantic notions that play an important role throughout much of
Ockham’s philosophy. None of these notions is original with Ockham,
although he develops them with great sophistication and employs them
with skill.

The most basic such notion is “signification.” For the
Middle Ages, a term “signifies” what it makes us think
. This notion of signification was unanimously accepted;
although there was great dispute over what terms signified,
there was agreement over the

Ockham, unlike many (but no means all) other medieval logicians, held
that terms do not in general signify thought, but can signify anything
at all (including things not presently existing). The function of
language, therefore, is not so much to communicate thoughts from one
mind to another, but to convey information about the

In Summa of Logic I.33, Ockham acknowledges four different
kinds of signification, although the third and fourth kinds are not
clearly distinguished. In his first sense, a term signifies whatever
things it is truly predicable of by means of a present-tensed,
assertoric copula. That is, a term t signifies a thing
x if and only if ‘This is a t’ is true,
pointing to x. In the second sense, t signifies

x if and only if ‘This is (or was, or will be, or can
be) a t’ is true, pointing to
These first two senses of signification are together called
“primary” signification.

In the third and fourth senses, terms can also be said to signify
certain things they are not truly predicable of, no matter the
tense or modality of the copula. For instance, the word
‘brave’ not only makes us think of brave people (whether
presently existing or not); it also makes us think of the

bravery in virtue of which we call them “brave.”
Thus, ‘brave’ signifies and is truly predicable of brave
people, but also signifies bravery, even though it is not truly
predicable of bravery. (Bravery is not brave.) This kind of
signification is called “secondary” signification.
a first approximation, then, we can say that what a term secondarily
signifies is exactly what it signifies but does not primarily
signify. Again to a first approximation, we can say that a
“connotative” term is just a term that has a secondary
signification, and that such a connotative term “connotes”
exactly what it secondarily signifies; in short, connotation is just

The theory of supposition was the centerpiece of late medieval
semantic theory. Supposition is not the same as signification. First of
all, terms signify wherever we encounter them, whereas they have
supposition only in the context of a proposition. But the differences
go beyond that. Whereas signification is a psychological, cognitive
relation, the theory of supposition is, at least in part, a theory of
reference. For Ockham, there are three main kinds of

  • Personal supposition, in which a term supposits for (refers to)
    what it signifies (in either of the first two senses of signification
    described above). For example, in ‘Every dog is a mammal’,
    both ‘dog’ and ‘mammal’ have personal
  • Simple supposition, in which a term supposits for a concept it does
    not signify. Thus, in ‘Dog is a species’ or ‘Dog is a
    universal’, the subject ‘dog’ has simple supposition.
    For Ockham the nominalist, the only real universals are universal
    concepts in the mind and, derivatively, universal spoken or written
    terms expressing those concepts.
  • Material supposition, in which a term supposits for a spoken or
    written expression it does not signify. Thus, in ‘Dog has three
    letters’, the subject ‘dog’ has material

Personal supposition, which was the main focus, was divided into
various subkinds, distinguished in terms of a theory of “descent
to singulars” and “ascent from singulars.” A quick
example will give the flavor: In ‘Every dog is a mammal’,
‘dog’ is said to have “confused and
distributive” personal supposition insofar as

  • It is possible to “descend to singulars” as follows:
    “Every dog is a mammal; therefore, Fido is a mammal, and Rover is
    a mammal, and Bowser is a mammal …,” and so on for all
  • It is not possible to “ascend from any one
    singular” as follows: “Fido is a mammal; therefore, every
    dog is a mammal.”

Although the mechanics of this part of supposition theory are well
understood, in Ockham and in other authors, its exact purpose remains a
mystery. Although at first the theory looks like an account of truth
conditions for quantified propositions, it will not work for that
purpose. And although the theory was sometimes used as an aid to
spotting and analyzing fallacies, this was never done systematically
and the theory is in any event ill suited for that

3.3 Mental Language, Synonymy, and Connotation

Ockham was perhaps the first person to give not just lip service to
the notion of “mental language” (because Aristotle and
Boethius had mentioned it), but actually to develop the notion in some
detail and to put it to work for
Written language for Ockham is “subordinated” to spoken
language, and spoken language is “subordinated” to mental
language. For Ockham, the terms of mental language are concepts; its
propositions are mental judgments. Whereas the signification of terms
in spoken and written language is purely conventional and can be
changed (hence in English we say ‘dog’ whereas in Latin it
is ‘canis’), the signification of terms
(concepts) in mental language is established by nature once and for
all. Concepts “naturally signify” what they are concepts
of; this “natural signification” is thought of as a kind
of representation relation, based on the fact that concepts are in
some way “naturally similar” to their objects.

This arrangement provides an account of synonymy (both
interlinguistic and intralinguistic) and equivocation in spoken and
written language. Two terms (whether from the same or different
spoken/written languages) are synonymous if and only if they
are subordinated to the same concept; a single given term of
spoken/written language is equivocal if and only if it is
subordinated to more than one concept simultaneously.

This raises an obvious question: Is there synonymy or equivocation in
mental language itself? (If there is, it will obviously have to be
accounted for in some other way than for spoken/written language.) A
great deal of modern secondary literature has been devoted to this
question. Trentman [1970] was the first to argue that no, there is no
synonymy or equivocation in mental language. On the contrary, he
argued, mental language for Ockham is a kind of lean, stripped down,
“canonical” language with no frills or inessentials, a
little like the “ideal languages” postulated by logical
atomists in the first part of the twentieth century. Spade [1980]
likewise argued in greater detail, on both theoretical and textual
grounds, that there is no synonymy or equivocation in mental language.
More recently, Panaccio [1990] and [2004], Tweedale [1992] (both on
largely textual grounds), and Chalmers [1999] (on mainly theoretical
grounds) have argued the contrary case for synonymy, that Ockham
did—or, for Chalmers, at least should
have—allowed for certain kinds of mental synonymy.

The situation is complicated, but it goes to the heart of much of
what Ockham is up to. In order to see why, let us return briefly to the
theory of
Connotation was described
in terms of primary and secondary
signification. But in Summa of Logic I.10, Ockham himself
draws the distinction between absolute and connotative terms by means
of the theory of definition.

For Ockham, there are two kinds of definitions: real
definitions and nominal definitions. A real definition is
somehow supposed to reveal the essential metaphysical structure of what
it defines; nominal definitions do not do that. As Ockham sets it up,
all connotative terms have nominal definitions, never real
definitions, and absolute terms (although not all of them)
have real definitions, never nominal definitions. (Some absolute terms
have no definitions at

As an example of a real definition, consider: ‘Man is a rational
animal’ or ‘Man is a substance composed of a body and an
intellective soul’. Each of these traditional definitions is
correct, and each in its own way expresses the essential metaphysical
structure of a human being. But notice: the two definitions do not
signify (make us think of) exactly the same things. The first
one makes us think of all rational things (in virtue of the first word
of the definiens) plus all animals (whether rational or not, in virtue
of the second word of the definiens). The second definition makes us
think of, among other things, all substances (in virtue of the word
‘substance’ in the definiens), whereas the first one does
not. It follows therefore that an absolute term can have several
distinct real definitions that don’t always signify exactly the same
things. They will primarily signify—be truly predicable
of—exactly the same things, since they will primarily signify
just what the term they define primarily signifies. But they can also
(secondarily) signify other things as

Nominal definitions, Ockham says, are different. Like real
definitions, there can be several distinct nominal definitions of the
same connotative term. But in the case of nominal definitions, all the
definitions of a given term will signify exactly the same things in
exactly the same ways. This is a very strong claim, and
appears to mean that for Ockham all nominal definitions of a given
connotative term are synonymous. Furthermore, Ockham seems to think of
connotative terms as in effect a kind of shorthand abbreviation for
their nominal definitions. If all this is so, then it means that not
only are all the nominal definitions of a given connotative term
synonymous with one another; they are also all synonymous with the term
they define.

If, therefore, there is no synonymy in mental language, it follows
that there will be no connotative terms in mental language either. Or,
more carefully put, either there are no simple
connotative terms in mental language, or else, if there are,
then mental language does not have the wherewithal to formulate their
(complex) nominal definitions. The latter hypothesis would seem to
cripple mental language entirely. Hence the prevailing view until
approximately 1990 was that for Ockham there are no simple

connotative terms in mental language. There are connotative
expressions there, but all of them are complex expressions that, if one
wants to put it this way, can in a “degenerate” sense (as
mathematicians speak of “degenerate” cases) be said to
serve as their own nominal definitions. It remains that no two
expressions of mental language are synonymous.

But in 1990 Claude Panaccio published a paper that showed once and
for all that Ockham did hold that there are simple connotative terms in
mental language. He says it explicitly and repeatedly, and in a variety
of texts (just not the texts that had been previously focused on).
Since that time the secondary literature seems to have gradually
converged on the view that, for Ockham, there is no synonymy among
simple terms in mental language, but that synonymy
can occur there between simple terms and complex expressions,
or between various complex expressions.

It should be emphasized that these matters are far from settled, and
some of the claims above are controversial. Readers should nevertheless
be aware of the issues. For much perhaps rests on them. This is because
Ockham’s use of connotation theory is crucial to his ontological

For Ockham, absolute terms are a guide to ontology. Because
Ockham thinks that, in the normal course of events, we get the
absolute terms of our mental language from a direct experience of the
things they signify, it follows that absolute terms are truly
predicable of (past or present) things. But connotative terms
are not like that; we can and do have connotative terms for all sorts
of things that have never existed—even for things that
cannot exist, like (according to the medieval view)
‘chimera’ and ‘vacuum’.

Since simple connotative terms are in effect shorthand abbreviations
for their nominal definitions, they can be systematically eliminated
and replaced by those nominal definitions without loss of expressive
power. If those nominal definitions in turn contain further connotative
terms of their own, the latter can in turn be expanded into their own
nominal definitions. And so on, until we arrive at a fully expanded
nominal definition of the original, simple connotative term, a
definition that consists only of absolute terms and of various
syncategorematic expressions.

At least that has seemed until recently to be the goal. If this
picture is correct, then what Ockham tries to do is to eliminate the
need for many putative entities by parsing away all talk of them via
his theory of connotation. As we shall see, most of the Aristotelian
categories, for example, are needless “extras” in a
perfectly adequate ontology; we do not need any entities in those
putative categories.

Thus the question whether there is synonymy in mental language may be
crucial to our understanding of the success of Ockham’s overall
ontological project. Since spoken or written language is semantically
derivative on mental language, it is vital that we get the semantics
of mental language to work out right for Ockham, or else the
systematic coherence of much of what he has to say will be in

Recent work, particularly Panaccio [2004], has begun to raise
suspicions about some parts of the interpretation just
presented. Indeed, it must be admitted that this interpretation does
make Ockham’s mental language look perhaps all too much like the
reductive, canonical, ideal languages of twentieth-century logical
atomism. This is not the place to rehearse all the details. But
readers should be aware that a new picture of Ockham’s mental language
may be emerging.

4. Metaphysics

Ockham was a nominalist, indeed he is the person whose name is
perhaps most famously associated with nominalism. But nominalism means
many different things:

  • A denial of metaphysical universals. Ockham was emphatically a
    nominalist in this sense.
  • An emphasis on reducing one’s ontology to a bare minimum, on paring
    down the supply of fundamental ontological categories. Ockham was
    likewise a nominalist in this sense.
  • A denial of “abstract” entities. Depending on what one
    means, Ockham was or was not a nominalist in this sense. He believed in
    “abstractions” such as whiteness and
    humanity, for instance, although he did not believe they were
    universals. (On the contrary, there are as many distinct whitenesses as
    there are white things.) He certainly believed in immaterial
    entities such as God and angels. He did not believe in mathematical
    (“quantitative”) entities of any kind.

The first two kinds of nominalism listed above are independent of
one another. Historically, there have been philosophers who denied
metaphysical universals, but allowed (individual) entities in more
ontological categories than Ockham does. Conversely, one might reduce
the number of ontological categories, and yet hold that universal
entities are needed in the categories that remain.

4.1 Ockham’s Razor

Still, Ockham’s “nominalism,” in both the first and the
second of the above senses, is often viewed as derived from a common
source: an underlying concern for ontological parsimony. This is summed
up in the famous slogan known as “Ockham’s Razor,” often
expressed as “Don’t multiply entities beyond
Although the sentiment is certainly Ockham’s, that particular
formulation is nowhere to be found in his texts. Moreover, as usually
stated, it is a sentiment that virtually all philosophers,
medieval or otherwise, would accept; no one wants a needlessly bloated
ontology. The question, of course, is which entities are needed and
which are not.

Ockham’s Razor, in the senses in which it can be found in Ockham
himself, never allows us to deny putative entities; at best it
allows us to refrain from positing them in the absence of known
compelling reasons for doing so. In part, this is because human beings
can never be sure they know what is and what is not “beyond
necessity”; the necessities are not always clear to us. But even
if we did know them, Ockham would still not allow that his Razor allows
us to deny entities that are unnecessary. For Ockham, the only
truly necessary entity is God; everything else, the whole of creation,
is radically contingent through and through. In short, Ockham does not
accept the Principle of Sufficient Reason.

Nevertheless, we do sometimes have sufficient methodological grounds
for positively affirming the existence of certain things. Ockham
acknowledges three sources for such grounds (three sources of positive
knowledge). As he says in Sent. I, dist. 30, q. 1: “For
nothing ought to be posited without a reason given, unless it is
self-evident (literally, known through itself) or known by
experience or proved by the authority of Sacred Scripture.”

4.2 The Rejection of Universals

In the case of universal entities, Ockham’s nominalism is
not based on his Razor, his principle of parsimony. That
is, Ockham does not hold merely that there is no good reason for
affirming universals, so that we should refrain from doing so in the
absence of further evidence. No, he holds that theories of universals,
or at least the theories he considers, are outright
incoherent; they either are self-contradictory or at least
violate certain other things we know are true in virtue of the three
sources just cited. For Ockham, the only universal entities it makes
sense to talk about are universal concepts, and derivative on
them, universal terms in spoken and written language. Metaphysically,
these “universal” concepts are singular entities like all
others; they are “universal” only in the sense of being
“predicable of many.”

But this was a view Ockham came to gradually. Over the course of his
career, Ockham changed his view of what universal concepts are. To
begin with, he adopted what is known as the fictum-theory, a
theory according to which universals have no “real”
existence at all in the Aristotelian categories, but instead are purely
“intentional objects” more or less in the sense of modern
phenomenology; they have only a kind of “thought”-reality.
Such “fictive” objects were metaphysically universal; they
just weren’t real. Eventually, however, Ockham came to think this
intentional realm of “fictive” entities was not needed, and
by the time of his Summa of Logic and the Quodlibets adopted
instead a so called intellectio-theory, according to which a
universal concept is just the act of thinking about several
objects at once; metaphysically it is quite singular, and is
“universal” only in the sense of being predicable of

4.3 Exposition or Parsing Away Entities

Thus, Ockham is quite certain there are no metaphysically universal
entities. But when it comes to paring down the number of basic
ontological categories, he is more cautious, and it is there that he
uses his Razor ruthlessly—always to suspend judgment, never to

The main vehicle for this “ontological reduction” is the
theory of connotation, coupled with the related theory of
“exposition.” The theory of exposition, which is not fully
developed in Ockham, will become increasingly prominent in authors
immediately after him. In effect, the theory of connotation is related
to the theory of exposition as explicit definition is related to
contextual definition. The notion of the “square” of a
number can be explicitly defined, for example, as the result of
multiplying that number by itself. Contextual definition operates not
at the level of terms, but at the level of propositions. Thus, Bertrand
Russell famously treated ‘The present king of France is
bald’ as amounting to ‘There is an x such that
x is a present king of France and x is bald, and for
all y if y is a present king of France then

y = x’. We are never given any outright
definition of the term ‘present king of France’, but
instead are given a technique of paraphrasing away seemingly
referential occurrences of that term in such a way that we are not
committed to any actually existing present kings of France. So too,
Ockham tries to provide us, at the propositional level, with
paraphrases of propositions that seem at first to refer to entities he
sees no reason to believe

For example, in Summa of Logic, II.11, among other places,
Ockham argues that we can account for the truth of ‘Socrates is similar
to Plato’ without having to appeal to a relational entity called

For example, for the truth of ‘Socrates is similar to
Plato’, it is required that Socrates have some quality and that
Plato have a quality of the same species. Thus, from the very fact that
Socrates is white and Plato is white, Socrates is similar to Plato and
conversely. Likewise, if both are black, or hot, [then] they are
similar without anything else added. (Emphasis

this way, Ockham removes all need for entities in seven of the
traditional Aristotelian ten categories; all that remain are entities
in the categories of substance and quality, and a few entities in the
category of relation, which Ockham thinks are required for theological
reasons pertaining to the Trinity, the Incarnation and the Eucharist,
even though our natural cognitive powers would see no reason for them
As is to be expected, the ultimate success
of Ockham’s program is a matter of considerable

5. Natural Philosophy

Ockham’s “physics” or natural philosophy is of a broadly
Aristotelian sort, although he interprets Aristotle in his own fashion.
Ockham wrote a great deal in this area; indeed his Exposition
of Aristotle’s Physics
is his longest work except for his
Commentary on the Sentences.[31]

As a nominalist about universals, Ockham had to deal with the
Aristotelian claim in the Posterior Analytics that science is
about what is universal and necessary. He discusses this issue in the
Prologue to his Exposition of the
and there agrees with Aristotle. But he interprets Aristotle’s dictum
as saying that science is about certain propositions with general
(universal) terms in them; it is only in that sense that science deals
with the universal. This of course does not mean that for Ockham our
scientific knowledge can never get beyond the level of language to
actual things. He distinguishes various senses of ‘to
know’ (scire, from which we get scientia or

  • In one sense, to “know” is to know a proposition, or a
    term in that proposition. It is in this sense that the object of a
    science is universal, and this is what Aristotle had in mind.
  • In another sense, we can be said to “know” what the
    proposition is about, what its terms have supposition for. What we
    “know” in that sense is always metaphysically individual,
    since for Ockham there isn’t anything else. This is not the sense in
    which Aristotle was speaking.

As described
Ockham holds that we do not need to allow entities in all ten of
Aristotle’s categories. In particular, we do not need them in the
category of quantity. For Ockham, there is no need for real
“mathematical” entities—numbers, points, lines,
surfaces, solids (in the geometrical sense). Talk about such things
can invariably be parsed away, via the theory of connotation or
exposition, in favor of talk about substances and qualities (and, in
certain theological contexts, a few relations). This Ockhamist move is
illustrative of and influential on an important development in late
medieval physics: the application of mathematics to non-mathematical
things, culminating in Galileo’s famous statement that the “book
of nature” is written in the “language of

Such an application of mathematics violates a traditional Aristotelian
prohibition against metabasis eis allo genos, grounded on
quite reasonable considerations. The basic idea is that things cannot
be legitimately compared in any respect in which they differ in
species. Thus it makes little sense to ask whether the soprano’s high
C is higher or lower than Mount Everest—much less to ask
(quantitatively) how much higher or lower it is. But for
Aristotle, straight lines and curved lines belong to different species
of lines. Hence they cannot be meaningfully compared or measured
against one another. The same holds for rectilinear motion and
circular motion.

Although the basic idea is reasonable enough, Ockham recognized that
there are problems. The length of a coiled rope, for example, can
straightforwardly be compared to the length of an uncoiled rope, and
the one can meaningfully be said to be longer or shorter than, or
equal in length to, the other. For that matter, a single rope
surely stays the same length, whether it is coiled or extended
full-length. Ockham’s solution to these problems is to note that, on
his ontology, straight lines and curved lines are not really

different species of lines—because lines are not really
things in the first place. Talk about lines is simply a “manner
of speaking” that can be parsed (“expounded”)

Thus, to compare a “curved” (coiled) rope with a
“straight” (uncoiled) one is not really to talk about the
lengths of lines in two different species; it is to talk about two
ropes, which are after all in the same species. To
describe the one as curved (coiled) and the other as straight
(uncoiled) is not to appeal to specifically different kinds of
entities—curvature and straightness—but merely to describe
the ropes in ways that can be expounded according to two different
patterns. Since such talk does not have ontological implications that
require specifically different kinds of entities, the Aristotelian
prohibition of metabasis does not apply.

Once one realizes that we can appeal to connotation theory, and more
generally the theory of exposition, without invoking new entities, the
door is opened to applying mathematical analyses (all of which are
exponible, for Ockham) to all kinds of things, and in particular to
physical nature.

Ockham’s contributions were by no means the only factor in the
increasing mathematization of science in the fourteenth century. But
they were important

6. Theory of Knowledge

Like most medieval accounts of knowledge, Ockham’s is not much
concerned with answering skeptical doubts. He takes it for granted
that humans not only can but frequently do know things, and focuses
his attention instead on the “mechanisms” by which this
knowledge comes about.

6.1 The Rejection of Species

Ockham’s theory of knowledge, like his natural philosophy, is
broadly Aristotelian in form, although—again, like his natural
philosophy—it is “Aristotelian” in its own way. For
most Aristotelians of the day, knowledge involved the transmission of a

between the object and the mind. At the sensory level, this species
may be compared to the more recent notion of a sense
“impression.” More generally, we can think of it as the
structure or configuration of the object, a structure or configuration
that can be “encoded” in different ways and found
isomorphically in a variety of contexts. One recent author, describing
the theory as it occurs in Aquinas, puts it like

Consider, for example, blueprints. In a blueprint of a
library, the configuration of the library itself, that is, the very
configuration that will be in the finished library, is captured on
paper but in such a way that it does not make the paper itself into a
library. Rather, the configuration is imposed on the paper in a
different sort of way from the way it is imposed on the materials of
the library. What Aquinas thinks of as transferring and preserving a
configuration we tend to consider as a way of encoding

The configuration of features found in the external object is also
found in “encoded” form as a species in the organ that
senses the object. (Depending on the sense modality, it may also be
found in an intervening medium. For example, with vision and hearing,
the species is transmitted through the air to the sense organ.) At the
intellectual level, the so called “agent intellect” goes to
work on this species and somehow produces the universal concept that is
the raw material of intellectual

Ockham rejected this entire theory of species. For him, species are
unnecessary to a successful theory of cognition, and he dispenses with
Moreover, he argues, the species theory is
not supported by experience; introspection reveals no such species in
our cognitive

On Ockham’s interpretation of the species theory, the agent
intellect’s work of “abstracting” the universal concept
from the quite individual sensible species is a process of
“filtering,” “subtracting” or
“extracting”; we disregard the peculiar features of
individual instances and retain only what is common to all of them. On
such an account, what the agent intellect produces as the result of its
work must already be present (together with the
“individual” features that are disregarded) in the species
it takes as its starting point, and ultimately in the original object.
Thus, if the process results in a universal concept, the
universal must have been really present in the object at the outset. As
a nominalist about universals, Ockham will therefore not accept this

Ockham’s rejection of the species theory of cognition was an
important development in late medieval

6.2 Intuitive and Abstractive Cognition

One of the more intriguing features of late medieval epistemology in
general, and of Ockham’s view in particular, is the development of a
theory known as “intuitive and abstractive cognition.” The
theory is found in authors as diverse as Duns Scotus, Peter Auriol,
Walter Chatton, and Ockham. But their theories of intuitive and
abstractive cognition are so different that it is hard to see any one
thing they are all supposed to be theories of. Nevertheless, to a
first approximation, intuitive cognition can be thought of as
perception, whereas abstractive cognition is closer to imagination or
remembering. The fit is not exact, however, since authors who had a
theory of intuitive and abstractive cognition usually also allowed the
distinction at the intellectual level as well.

It is important to note that abstractive cognition, in the sense of
this theory, has nothing necessarily to do with
“abstraction” in the sense of producing universal concepts
from cognitive encounters with individuals. Instead, what abstractive
cognition “abstracts” from is the question of the
existence or non-existence of the object. By contrast,
intuitive cognition is very much tied up with the existence or
non-existence of the object. Here is how Ockham distinguishes

For intuitive cognition of a thing is a cognition such that
by virtue of it it can be known whether the thing exists or not, in
such a way that if the thing does exist, the intellect at once judges
it to exist and evidently knows it to exist … Likewise,
intuitive cognition is such that when some things are known, one of
which inheres in the other or the one is distant in place from the
other or is related in another way to the other, it is at once known by
virtue of the incomplex cognitions of those things whether the thing
inheres or does not inhere, whether it is distant or not distant, and
so on for other contingent truths …

Abstractive cognition, however, is that by virtue of which it cannot
be evidently known of the thing whether it exists or does not exist.
And in this way abstractive cognition, as opposed to intuitive
cognition, “abstracts” from existence and non-existence,
because by it neither can it be evidently known of an existing thing
that it exists, nor of a non-existent one that it does not exist.

The correct interpretation of Ockham’s theory of intuitive and
abstractive cognition is a matter of considerable controversy. The
“standard” view holds that intuitive cognition for Ockham
grounds infallible judgments, whereas abstractive cognition
does not. Recently, however, this view has been questioned on the
grounds that it is based on a misreading of a certain text. The issues
are complex and subtle, and the matter has not yet been finally sorted

7. Ethics

Ockham’s ethics combines a number of themes. For one, it is a
will-based ethics in which intentions count for everything and
external behavior or actions count for nothing. In themselves, all
actions are morally neutral.

Again, there is a strong dose of divine command theory in Ockham’s
ethics. Certain things (i.e., in light of the previous point, certain
intentions) becomes morally obligatory, permitted or forbidden
simply because God decrees so. Thus, in Exodus, the Israelites’
“spoiling the Egyptians” (or rather their
intention to do so, which they carried out) was not a matter
of theft or plunder, but was morally permissible and indeed
obligatory—because God had commanded it.

Nevertheless, despite the divine command themes in Ockham’s ethics,
it is also clear that he wanted morality to be to some extent a matter
of reason. There is even a sense in which one can find a kind of
natural law theory in Ockham’s ethics; one way in which God conveys his
divine commands to us is by giving us the natures we
Unlike Augustine, Ockham accepted the possibility of the
“virtuous pagan”; moral virtue for Ockham does not depend
on having access to revelation.

7.1 The Virtues

But while moral virtue is possible even for the pagan, moral virtue
is not by itself enough for salvation. Salvation requires not just
virtue (the opposite of which is moral vice) but merit (the opposite of
which is sin), and merit requires grace, a free gift from God. In
short, there is no necessary connection between virtue—moral
goodness—and salvation. Ockham repeatedly emphasizes that
“God is a debtor to no one”; he does not owe us
anything, no matter what we do.

For Ockham, acts of will are morally virtuous either extrinsically,
i.e. derivatively, through their conformity to some more fundamental
act of will, or intrinsically. On pain of infinite regress, therefore,
extrinsically virtuous acts of will must ultimately lead back to an
intrinsically virtuous act of will. That intrinsically virtuous act of
will, for Ockham, is an act of “loving God above all else and for
his own sake.”

In his early work, On the Connection of the Virtues, Ockham
distinguishes five grades or stages of moral virtue, which have been
the topic of considerable speculation in the secondary

  1. The first and lowest stage is found when someone wills to act in
    accordance with “right reason”—i.e., because it is
    “the right thing to do.”
  2. The second stage adds moral “seriousness” to the
    picture. The agent is willing to act in accordance with right reason
    even in the face of contrary considerations, even—if
    necessary—at the cost of death.
  3. The third stage adds a certain exclusivity to the motivation; one
    wills to act in this way only because right reason requires
    it. It is not enough to will to act in accordance with right reason,
    even heroically, if one does so on the basis of extraneous, non-moral
  4. At the fourth stage of moral virtue, one wills to act in this way
    “precisely for the love of God.” This stage “alone is
    the true and perfect moral virtue of which the Saints
  5. The fifth and final stage can be built immediately on either the
    third or the fourth stage; thus one can have the fifth without the
    fourth stage. The fifth stage adds an element of extraordinary moral
    heroism that goes beyond even the “seriousness” of stage

The difficulty in understanding this hierarchy comes at the fourth
stage, where it is not clear exactly what moral factor is
added to the preceding three

7.2 Moral Psychology

At the beginning of his Nicomachean Ethics, Aristotle
remarked that “the good is that at which all things aim.”
Each thing, therefore, aims at the good, according to the demands of
its nature. In the Middle Ages, “Aristotelians” like Thomas
Aquinas held that the good for human beings in particular is
“happiness,” the enjoyment of the direct vision of God in
the next life. And, whether they realize it or not, that is what all
human beings are ultimately aiming at in their actions. For someone
like Aquinas, therefore, the human will is “free” only in a
certain restricted sense. We are not free to choose for or
against our final end; that is built into us by nature. But we are free
to choose various means to that end. All our choices,
therefore, are made under the aspect of leading to that final goal. To
be sure, sometimes we make the wrong choices, but when that occurs it
is because of ignorance, distraction, self-deception, etc. In an
important sense, then, someone like Aquinas accepts a version of the so
called Socratic Paradox: No one knowingly and deliberately does

Ockham’s view is quite different. Although he is very suspicious of
the notion of final causality (teleology) in general, he thinks it is
quite appropriate for intelligent, voluntary agents such as human
beings. Thus the frequent charge that Ockham severs ethics from
metaphysics by denying teleology seems
Nevertheless, while Ockham grants that human beings have a natural
orientation, a tendency toward their own ultimate good, he does not
think this restricts their choices.

For Ockham, as for Aristotle and Aquinas, I can choose the means to
achieve my ultimate good. But in addition, for Ockham unlike Aristotle
and Aquinas, I can choose whether to will that ultimate good.
The natural orientation and tendency toward that good is built in; I
cannot do anything about that. But I can choose whether or not
to to act to achieve that good. I might choose, for example,
to do nothing at all, and I might choose this knowing full well what I am
doing. But more: I can choose to act knowingly directly

against my ultimate good, to thwart
I can choose evil as evil.

For Ockham, this is required if I am going to be morally responsible
for my actions. If I could not help but will to act to achieve my
ultimate good, then it would not be morally praiseworthy of me to do
so; moral “sins of omission” would be impossible (although
of course I could be mistaken in the means I adopt). By the same
token, moral “sins of commission” would be impossible if I
could not knowingly act against my ultimate good. But for
Ockham these conclusions are not just required by theory; they are
confirmed by experience.

8. Political Philosophy

The divine command themes so prominent in Ockham’s ethics are much
more muted in his political theory, which on the contrary tends to be
far more “natural” and

As sketched
Ockham’s political writings began at Avignon with a discussion of the
issue of poverty. But later on the issues were generalized to include
church/state relations more broadly. He was one of the first medieval
authors to advocate a form of church/state separation, and was
important for the early development of the notion of property

The Franciscan Order at this time was divided into two parties, which
came to be known as the “Conventuals” and the
“Spirituals” (or “zealots”). The Spirituals,
among whom were Ockham, Michael of Cesena, and the other exiles who
joined them in fleeing Avignon, tried to preserve the original ideal
of austere poverty practiced and advocated by St. Francis himself (c.
1181-1226). The Conventuals, on the other hand, while recognizing this
ideal, were prepared to compromise in order to accommodate the
practical needs of a large, organized religious order; they were by
far the majority of the order. The issue between the two parties was
never one of doctrine; neither side accused the other of
heresy. Rather, the question was one of how to shape and run the
order—in particular, whether the Franciscans should (or even
could) renounce all property rights.

8.1 The Ideal of Poverty

The ideal of poverty had been (and still is) a common one in religious
communities. Typically, the idea is that the individual member of the
order owns no property at all. If a member buys a car, for instance,
it is not strictly his car, even though he may have exclusive use of
it, and it was not bought with his money; he doesn’t have any money of
his own. Rather it belongs to the order.

The original Franciscan ideal went further. Not only did the
individual friar have no property of his own, neither did the
. The Franciscans, therefore, were really supposed to be
“mendicants,” to live by begging. Anything donated to the
order, such as a house or a piece of land, strictly speaking remained
the property of the original owner (who merely granted the use
of it to the Franciscans). (Or, if that would not work—as, for
example, in the case of a bequest in a will, after the original owner
had died—the ownership would go to the Papacy.)

Both the Spirituals and the Conventuals thought this ideal of
uncompromising poverty was exhibited by the life of Jesus and the
Apostles, who—they said—had given up all property, both
individually and collectively. St. Francis regarded this as
the clear implication of several Scriptural passages: e.g., Matt.
6:24-34, 8:20, 19:21. In short, the Apostolic (and Franciscan) ideal
was, “Live without a safety net.”

Of course, if everyone lived according to this ideal, so that no one
owned any property either individually or collectively, then there
would be no property at all. The Franciscan ideal, then, shared by
Conventuals and Spirituals alike, entailed the total abolition of
all property rights.

Not everyone shared this view. Outside the Franciscan order, most
theoreticians agreed that Jesus and the Apostles lived without
individual property, but thought they did share property collectively.
Nevertheless, Pope Nicholas III, in 1279, had officially approved the
Franciscan view, not just as a view about how to organize the
Franciscan order, but about the interpretation of the Scriptural
passages concerning Jesus and the Apostles. His approval did not mean
he was endorsing the Franciscan reading as the correct
interpretation of Scripture, but only that it was a
permissible one, that there was nothing doctrinally suspect

Nevertheless, this interpretation was a clear reproach to the
Papacy, which at Avignon was wallowing in wealth to a degree it had
never seen before. The clear implication of the Franciscan view,
therefore, was that the Avignon Popes were conspicuously not

living their lives as an “imitation of Christ.” Whether for
this reason or another, the Avignon Pope John XXII decided to reopen
discussion of the question of Apostolic poverty and to come to some
resolution of the matter. But, as Mollat [1963] puts it (perhaps not
without some taking of

When discussions began at Avignon, conflicting opinions
were freely put forward. Meanwhile, Michael of Cesena, acting with
insolent audacity, did not await the Holy See’s decision: on 30 May
1322 the chapter-general [of the Franciscan order] at Perugia declared
itself convinced of the absolute poverty of Christ and the

It was this act that provoked John XXII to issue his first
contribution to the dispute, his bull Ad conditorem in 1322.
There he put the whole matter in a legal framework.

8.2 The Legal Issues

According to Roman law, as formulated in the Code of Justinian,
“ownership” and “legitimate use” cannot be
permanently separated. For example, it is one thing for me to
own a book but to let you use it for a while. Ownership in that case
means that I can recall the book, and even if I do not do so,
you should return it to me when you are done with it. But it is quite
another matter for me to own the book but to grant you
permanent use of it, to agree not to recall it as long as you
want to keep it, and to agree that you have no obligation to give it
back ever. John XXII points out that, from the point of view
of Roman law, the latter case makes no sense. There is no practical
difference in that case between your having the use of the book and your
owning it; for all intents and purposes, it is yours.

Notice the criticism here. It is a legal argument against the claim
that the Papacy as an institution can own something and yet the
Franciscans as an order, collectively, have a permanent right
to use it. The complaint is not against the notion that an
individual friar might have a right to use something until he dies, at
which time use reverts to the order (or as the Franciscans would have
it, to the Papacy). This would still allow some distinction between
ownership and mere use. Rather the complaint is against the notion that
the order would not own anything outright, but would nevertheless have
permanent use of it that goes beyond the life or death of any
individual friar, so that the ownership somehow remained permanently
with the Papacy, even though the Pope could not reclaim it, use it, or
do anything at all with it. John XXII argues that this simply abolishes
the distinction between use and ownership.

8.3 Property Rights

Special problems arise if the property involved is such that the use
of it involves consuming it—e.g., food. In that case, it
appears that there is no real difference between ownership and even
temporary use. For things like food, using them
amounts for practical purposes to owning them; they cannot be
recalled after they are used. In short, for John XXII, it follows that
it is impossible fully to live the life of absolute poverty,
even for the individual person (much less for a permanent institution
like the Franciscan order). The institution of property, and property
“rights,” therefore began in the Garden of Eden, the first
time Adam or Eve ate something. These property rights are not
“natural” rights; on the contrary, they are established by
a kind of positive law by God, who gave everything in the
Garden to Adam and Eve.

Ockham disagreed. For him, there was no “property” in
the Garden of Eden. Instead, Adam and Eve there had a natural
right to use anything at hand. This natural right did not
amount to a property right, however, since it could not have
been used as the basis of any kind of legal claim. Both John XXII and
Ockham seem to agree in requiring that “property”
(ownership) be a matter of positive law, not simply of natural law. But
John says there was such property in the Garden of Eden, whereas Ockham
claims there was not; there was only a natural right, so
that Adam and Eve’s use of the goods there was legitimate. For Ockham,
“property” first emerged only after the Fall when, by a
kind of divine permission, people began to set up special positive
legal arrangements assigning the legal right to use certain things to
certain people (the owners), to the exclusion of anyone else’s having a

legal right to them. The owners can then give
permission to others to use what the owners own, but that
permission does not amount to giving them a legal right they could
appeal to in a court of law; it can be revoked at any time. For Ockham,
this is the way the Franciscans operate. Their benefactors and donors
do not give them any legal rights to use the things donated to
them—i.e., no right they could appeal to in a court of law.
Rather the donation amounts only to a kind of permission that
restores the original natural (not legal) right of use in the Garden of


Primary Literature

In Latin

  • William of Ockham, 1967-88. Opera philosophica et
    . Gedeon Gál, et al., ed. 17 vols. St.
    Bonaventure, N. Y.: The Franciscan Institute.
  • —–, 1956-97. Opera politica. H. S. Offler, et
    ., ed. 4 vols. Vols. 1-3, Manchester: Manchester University
    Press, 1956-74. Vol. 4, Oxford: Oxford University Press, 1997. Contains
    all the political writings except the Dialogus.
  • —–, forthcoming. Dialogus. John Kilcullen and John
    Scott, ed. & trans. See
    Other Internet Resources,

In English Translation

A fair number of Ockham’s writings are available in English, in
whole or in part. For a complete list of translations to 1999, see
Spade [1999], pp. 5-11. The following major items deserve particular

  • Adams, Marilyn McCord, and Kretzmann, Norman, trans. 1983.
    William of Ockham: Predestination, God’s Foreknowledge, and Future
    . 2nd ed. Indianapolis: Hackett. Includes Ockham’s
    Treatise on Predestination and God’s Foreknowledge with Respect to
    Future Contingents
    , with introduction and commentary, and
    translations of related passages from other works of Ockham.
  • Birch, T. Bruce, ed. & trans. 1930. The De sacramento
    altaris of William of Ockham
    . Burlington, Iowa: Lutheran Literary
    Board. Translation of Ockham’s Treatise on Quantity and On
    the Body of Christ
    . (Despite Birch’s title, these two are

    not parts of a larger single work work De sacramento

  • Boehner, Philotheus, ed. & trans. 1990. William of Ockham:
    Philosophical Writings
    . Rev. ed. Indianapolis, Ind.: Hackett.
    (Original edition, London: Thomas Nelson, 1957.) Selections from
    several texts.
  • Bosley, Richard N., and Tweedale, Martin, trans. 1997. Basic
    Issues in Medieval Philosophy: Selected Readings Presenting the
    Interactive Discourse among the Major Figures
    . Peterborough
    (Canada): Broadview. Includes a translation of On the Eternity of
    the World
    and selections from other works of Ockham.
  • Davies, Julian, trans. 1989. Ockham on Aristotle’s Physics: A
    Translation of Ockham’s Brevis Summa Libri Physicorum
    . St.
    Bonaventure, N. Y.: The Franciscan Institute. Complete translation of
    the Brief Summa of the Physics.
  • Freddoso, Alfred J., and Kelly, Francis E., trans. 1991.
    Quodlibetal Questions. New Haven, Conn.: Yale University
  • Freddoso, Alfred J., and Schuurman, Henry, trans. 1980.
    Ockham’s Theory of Propositions: Part II of the Summa logicae.
    Notre Dame, Ind.: University of Notre Dame Press.
  • Kilcullen, John, and Scott, John, ed. & trans. forthcoming.
    Dialogus. See
    Other Internet Resources,
  • Kluge, Eike-Henner W., trans. 1973-74. “William of Ockham’s
    Commentary on Porphyry: Introduction and English Translation.”
    Franciscan Studies 33, pp. 171-254, and 34, pp. 306-82.
  • Loux, Michael J. 1974. Ockham’s Theory of Terms: Part I of the
    Summa Logicae
    . Notre Dame, Ind.: University of Notre Dame Press.
    Complete Translation.
  • McGrade, A. S., and Kilcullen, John, ed. & trans. 1992. A
    Short Discourse on the Tyrannical Government Over Things Divine and
    Cambridge: Cambridge University Press. Translation of
    Ockham’s Short Discourse.
  • —–, 1995. A Letter to the Friars Minor and Other
    . Cambridge: Cambridge University Press. Translation of
    several of Ockham’s political writings, including the Letter to the
    Friars Minor, Eight Questions on the Power of the Pope
    , and
    The Work of Ninety Days.
  • Spade, Paul Vincent, 1994. Five Texts on the Mediaeval Problem
    of Universals: Porphyry, Boethius, Abelard, Duns Scotus, Ockham
    Indianapolis, Ind.: Hackett. Includes a complete translation of
    Ockham’s discussion of universals from Sent. I.2.4-8.
  • Wood, Rega, trans. 1997. Ockham on the Virtues. West
    Lafayette, Ind.: Purdue University Press. Contains a translation of
    Ockham’s On the Connection of the Virtues, with the original
    Latin text, introduction and commentary.

Secondary Literature

Ample bibliographies of the secondary literature up to 1990 may be
found in:

  • Beckmann, Jan P., 1992. Ockham—Bibliographie:
    . Hamburg: Felix Meiner.
  • Heynick, Valens, 1950. “Ockham-Literatur: 1919-1949.”
    Franziskanische Studien 32, pp. 164-83.
  • Reilly, James P., 1968. “Ockham Bibliography,
    1950-1967.” Franciscan Studies 28, pp. 197-214.

The following list includes all works cited in this article, plus
several other noteworthy items:

  • Adams, Marilyn McCord, 1986. “The Structure of Ockham’s Moral
    Theory.” Franciscan Studies 29, pp. 1-35.
  • —–, 1987. William Ockham. 2 vols., Notre Dame, Ind.:
    University of Notre Dame Press. (2nd rev. ed., 1989.)
  • —–, 1999. “Ockham on Will, Nature, and Morality.” In
    Spade, [1999] Chap. 11 (pp. 245-72).
  • Ashworth, E. J., and Spade, Paul Vincent, 1992. “Logic in
    Late Medieval Oxford.” In J. I. Catto and T. A. R. Evans, ed.,
    History of the University of Oxford, Vol. 2: Late Medieval
    . Oxford: Clarendon Press. Chap. 2, pp. 35-64.
  • Boehner, Philotheus, 1946. “The Realistic Conceptualism of
    William Ockham.” Traditio 4, pp. 307-35.
  • Brampton, C. Kenneth, 1964. “Nominalism and the Law of
    Parsimony.” The Modern Schoolman 41, pp. 273-81.
  • Brown, Stephen F., 1972. “Walter Burleigh’s Treatise De
    and Its Influence on William of Ockham.”
    Franciscan Studies 32, pp. 15-64.
  • Chalmers, David, 1999. “Is There Synonymy in Ockham’s Mental
    Language?” In Spade [1999], Chap. 4 (pp. 76-99).
  • Courtenay, William J., 1999. “The Academic and Intellectual
    Worlds of Ockham.” In Spade [1999], Chap. 1 (pp. 17-30).
  • Freppert, Lucan, 1988. The Basis of Morality according to
    William Ockham
    . Chicago: Franciscan Herald Press.
  • Gál, Gedeon, 1982. “William of Ockham Died Impenitent
    in April 1347.” Franciscan Studies 42, pp. 90-95.
  • Goddu, André, 1984. The Physics of William of
    . Leiden: E. J. Brill.
  • —–, 1999. “Ockham’s Philosophy of Nature.” In Spade
    [1999], Chap. 7 (pp. 143-67).
  • Hirvonen, Vesa, 2004. Passions in William Ockham’s
    Philosophical Psychology.
    Dordrecht: Kluwer.
  • Karger,
    Elizabeth, 1976. A Study of William of Ockham’s Modal
    . Ph.D. dissertation: University of California.
  • —–, 1999. “Ockham’s Misunderstood Theory of Intuitive and
    Abstractive Cognition.” In Spade [1999], Chap 9 (pp.
  • King, Peter, 1999. “Ockham’s Ethical Theory.” In Spade
    [1999], Chap. 10 (pp. 227-44).
  • Kilcullen, John, 1999. “The Political Writings.” In
    Spade [1999], Chap. 13 (pp. 302-25).
  • Leppin, Volker, 2003. Wilhelm von Ockham: Gelehrter, Streiter,
    Darmstadt: Wissenschaftliche
  • Maurer, Armand A., 1962. Medieval Philosophy. New York:
    Random House.
  • —–, 1978. “Method in Ockham’s Nominalism.” The
    61, pp. 426-43.
  • —–, 1984. “Ockham’s Razor and Chatton’s Anti-Razor.”
    Mediaeval Studies 46, pp. 463-75.
  • —–, 1999. The Philosophy of William of Ockham in the Light
    of Its Principles.
    Toronto: Pontifical Institute of Mediaeval
  • McGrade, A. S., 1974. The Political Thought of William of
    . Cambridge: Cambridge University Press. (New edition,
  • —–, 1999. “Natural Law and Moral Omnipotence.” In
    Spade [1999], Chap. 12 (pp. 273-301).
  • Michon, Cyrille, 1994. Nominalisme: La théorie de la
    signification d’Occam.
    Paris: J. Vrin.
  • Mollat, G., 1963. The Popes in Avignon 1307-1378. London:
    Thomas Nelson.
  • Normore, Calvin G., 1975. The Logic of Time and Modality in the
    Later Middle Ages: The Contributio
    n of William of Ockham.
    Ph.D. dissertation: University of Toronto.
  • —–, 1999. “Some Aspects of Ockham’s Logic.” In Spade
    [1999], Chap. 2 (pp. 31-52).
  • Panaccio, Claude, 1990. “Connotative Terms in Ockham’s Mental
    Language.” Cahiers d’épistémologie, no.
    9016. Montréal: Université du Quebec à
  • —–, 1991. Les Mots, les Concepts et les Choses. Le
    sémantique de Guillaume d’Occam et le nominalisme
  • —–, 1999. Le Discours Intérieur: de Platon à
    Guillaume d’Ockham.
    Paris: Éditions de Seuil.
  • —–, 2003. “Debates on Mental Language in the Early
    Fourteenth Century.” In H. A. G. Braakhuis & C. H. Kneepkens
    (ed.) [2003], Aristotle’s Peri Hermeneias in the Latin Middle
    Groningen: Ingenium, pp. 85-101.
  • —–, 2004. Ockham on Concepts. Aldershot, England:
  • Spade, Paul Vincent, 1974. “Ockham on Self-Reference.”
    Notre Dame Journal of Formal Logic 15, pp. 298-300.
  • —–, 1975. “Ockham’s Distinctions between Absolute and
    Connotative Terms.” Vivarium 13, pp. 55-76.
  • —–, 1975a. “Some Epistemological Implications of the
    Burley-Ockham Dispute.” Franciscan Studies 35, pp.
  • —–, 1980. “Synonymy and Equivocation in Ockham’s Mental
    Language.” Journal of the History of Philosophy 18, pp.
  • —–, 1988. “The Logic of the Categorical: The Medieval
    Theory of Descent and Ascent.” In Norman Kretzmann (ed.) [1988],
    Meaning and Inference in Medieval Philosophy. Dordrecht:
    Kluwer, pp. 187-224.
  • —–, 1990. “Ockham, Adams and Connotation: A Critical
    Notice of Marilyn Adams, William Ockham.” The
    Philosophical Review
    99, pp. 593-612.
  • —–, 1998. “Three Versions of Ockham’s Reductionist
    Program.” Franciscan Studies 56, pp. 335-46.
  • —–, ed., 1999. The Cambridge Companion to Ockham. New
    York: Cambridge University Press.
  • —–, 1999a. “Ockham’s Nominalist Metaphysics: Some Main
    Themes.” In Spade [1999], Chap. 5 (pp. 100-117).
  • Stump, Eleonore, 1999. “The Mechanisms of Cognition: Ockham
    on Mediating Species.” In Spade [1999], Chap. 8 (pp.
  • Tauchau, Katherine H., 1988. Vision and Certitude in the Age of
    Ockham: Optics, Epistemology and the Foundations of Semantics,
    . Leiden: E. J. Brill.
  • Trentman, John, 1970. “Ockham on Mental.” Mind
    79, pp. 586-90.
  • Tweedale, Martin M., 1992. “Ockham’s Supposed Elimination of
    Connotative Terms and His Ontological Parsimony.”
    Dialogue 31, pp. 431-44.
  • Wood, Rega, 1999. “Ockham’s Repudiation of
    Pelagianism.” In Spade [1999], Chap. 15 (pp. 350-73).

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