34
INTRODUCTION TO JEAN BURIDAN’S LOGIC
sentential context—evaluating the truth of the sentence is another matter.
Hence it is a mistake to suppose that supposition theory will say exactly
which things a term in fact supposits for. Rather, supposition theory will
specify what things a term semantically supposits for, and then it is a sep-
arate question whether the supposition is successful. Failing to appreciate
this point can lead only to confusion.
6.2 Personal and Material Supposition
The general motive for distinguishing material and personal supposi-
tion is clear: a sign may be used to refer to things (its ultimate significates),
or it may be used to refer to other signs. In the former case a term has per-
sonal supposition; in the latter, material supposition.
54
For example, in the
sentence “Every man is running” the term ‘man’ has personal supposition;
we are asserting something about individual men, who are the ultimate sig-
nificates of the term ‘man.’ But in the sentences “Man has three letters,”
“Man has one syllable,” “Man is a concept,” the term ‘Man’ is used to talk
about not individual men, but rather an inscription, an utterance, and a con-
cept respectively, each of which is itself a sign. Note that the subject-terms
of all these sentences are the same.
55
Buridan defines personal supposition
as follows (TS 3.2.1):
Supposition is called ‘personal’ when a term supposits for its ulti-
mate significate(s).
Thus the term ‘man’ has personal supposition in the sentence “A man is
running”. The divisions of personal supposition, discussed in Sections 6.3-
7, describes which of its ultimate significates a term may supposit for in
particular. This same question is also at the heart of the theory of am-
pliation and restriction, discussed in Section 6.8, which analyzes how the
referential domain of a term in personal supposition may be either widened
or narrowed respectively. WE can generalize Buridan’s account in TS 1.2.9
to arrive at the following characterization of personal supposition:
A term t has personal supposition in a sentence if and only if either
(i ) some sentence of the form “This is t” is true, or (ii ) some clause
of the form ‘. . . and that is t’ can be added to an existential sentence
or a sentence presupposing an existential sentence to produce a true
sentence. The demonstrative or relative pronoun and the copula of
(i ) and (ii ) should be taken in the appropriate number, tense, and
54
This is too loose: the term ‘utterance’ personally supposits for signs. But it may serve
as a handy initial characterization.
55
Don’t worry about whether the examples of material supposition need quotation-
marks; that is one of the jobs performed by the theory of material supposition.
c Peter King, from Jean Buridan’s Logic (Dordrecht: D. Reidel 1985) 3–82.
INTRODUCTION TO JEAN BURIDAN’S LOGIC
35
mode.
The motivation for adding (i ) in TS 1.2.9 is to circumvent worries about
whether we can point to God, who is not open to direct inspection (in this
life), which might seem to be required for ostension. In fact (ii ) is more
general: it will serve to sidestep worries about “pointing to” past, future,
or possible existents as well, which are also not open to direct inspection.
Thus in the sentence “Some man will lecture tomorrow” the term ‘man’ has
personal supposition, since some sentence of the form “This is a man” is
true.
A term is in material supposition, on the other hand, if it does not
supposit for what it ultimately signifies (TS 3.2.1):
But supposition is called ‘material’ when an utterance supposits for
itself or something similar to itself or for its immediate significate,
which is the concept according to which it is imposed to signify, as
the term ‘man’ in the sentence ‘Man is a species.’
Logicians preceding Buridan posited another kind of supposition, simple
supposition, in which a term was taken to stand for a universal or common
nature. William of Ockham had retained simple supposition as a category,
but his nominalist scruples forced him to say that in simple supposition a
term supposits for the concept it immediately signifies, which, in the case
of common terms, simply is the universal. It was left to Buridan to see
this extra division of supposition as a relic of realism (TS 3.2.4-5): since
a concept is just as much a sign as an utterance or an inscription, albeit
naturally and not conventionally significative, Buridan drew the conclusion
that supposition for a concept as the immediate significate was just another
form of material supposition (TS 3.2.6).
Buridan argues that material supposition is proper only to Spoken
or Written, and that there is no material supposition in Mental: “no term in
a Mental sentence supposits materially, but always personally” (Summulae
de dialectica 7.3.4). Hence Buridan is not even faintly interested in divisions
of material supposition: such a series of divisions would only be of limited
interest to the logician, whose concern is with Mental and not with Spoken
or Written. Mental therefore has a complete apparatus to accomplish all of
the functions of material supposition. For example, the sentence “Man is a
species” is properly represented in Mental in the following way (Summulae
de dialectica 7.3.4):
I say that the Mental sentence corresponding to the sentence “Man is
a species” (taken as it is true) is not a sentence in which the specific
concept of man is put as the subject, but rather is a sentence in
which the concept by which the specific concept of man is conceived
c Peter King, from Jean Buridan’s Logic (Dordrecht: D. Reidel 1985) 3–82.