36
INTRODUCTION TO JEAN BURIDAN’S LOGIC
is put for the specific concept of man, from which it is clear that the
aforementioned paralogism is a fallacy in dictione by the change of
supposition.
The “aforementioned paralogism” is the argument “Man is a species, and
Socrates is (a) man; therefore, Socrates is a species.” It fails because there is
a change in supposition, perspicuously seen in Mental: the sentence “Man
is a species” is subordinated to the sentence “The concept by which the
specific concept of man is conceived is a species,” which is true: genera and
species are concepts of concepts, not individual general concepts themselves.
Material supposition acts like quotation in many ways, serving to
distinguish the use of a term from its mention, but the differences should
not be overlooked; material supposition is much wider than our use-mention
distinction. The similarities are obvious: in sentence such as “Man has three
letters” or “Man is a monosyllable” the term ‘man’ has material supposition;
we should render these by using the quote-functor, giving “ ‘Man’ has three
letters” or “ ‘Man’ is a monosyllable.” However, there are differences even
in such cases. First, applications of a quote-functor produces a new term,
one which names the personal or material supposition. Indeed, Buridan was
familiar with the device of naming expressions, but he never proposes it as
an account of material supposition.
56
Equally quotation does not seem to
require a sentential context the way material supposition does. Second, the
quote-functor may be iterated,
57
but material supposition cannot; there is
no mediæval analogue of the sentence “ ‘ ‘Socrates’ ’ names ‘Socrates’ names
Socrates, who was Greek.”
58
Material supposition could be no more than
a first-order fragment of quotation theory. Third, the substitution classes
differ; a term can materially supposit for what is only similar to it, so
that accusative-infinitive phrases supposit for sentences, and changes in case
and gender are permitted. In the composite modal sentence “It is possible
for Socrates to be a bishop: the expression ‘for Socrates to be a bishop’
materially supposits for the sentence “Socrates is a bishop” (or a similar
sentence).
Material supposition, then, is more inclusive than the distinction of
use and mention, even when we restrict ourselves to the material supposi-
56
Sometimes Buridan uses the mediæval French word ‘li’ or ‘ly’ prefixed to a term:
this however was not a mediæval quote-functor but rather a metalinguistic comment
indicating that the following term has material supposition.
57
Provided that no syntactic ambiguity arises, as would be the case in ‘ ‘p’ ’∧‘ ‘q’ ’: but
a scope convention will clarify such cases.
58
Unless such iteration can be accomplished through anaphoric reference: see the dis-
cussion of relative supposition in the next section.
c Peter King, from Jean Buridan’s Logic (Dordrecht: D. Reidel 1985) 3–82.
INTRODUCTION TO JEAN BURIDAN’S LOGIC
37
tion of utterances or inscription. Allowing material supposition of concepts
merely points up the relevant differences.
When is a term in personal supposition or in material supposition?
Unlike Ockham, Buridan does not try to give precise rules, but rather trusts
to good sense and good logic (TS 3.2.15-22), usually taking context to de-
cide. Since there is no material supposition in Mental, Buridan is not at
fault for not providing precise rules; the vagaries of Spoken or Written are
met individually.
6.3. Discrete and Common Supposition
We now properly begin the divisions of personal supposition, which
were drawn in an effort to clarify which of its significates a term is used to
refer to. By ‘discrete term’ Buridan means a singular referring expression—
that is, an expression which is predicable of only a single item. Hence it is
obvious when using a discrete term that one is talking about the very thing
the term refers to: there are no other choices. Hence personal supposition is
divided into discrete and common (TS 3.3.1). As examples of discrete terms
Buridan offers us ‘Socrates’ and ‘this man.’ Presumably all proper names
are discrete, despite the fact that two people may have the same name; the
‘name’ is not really common in this case. Demonstratives combined with
common terms are also discrete. Buridan never says so, but pure demon-
stratives should also be discrete terms. Any singular referring expression is,
as a matter semantics, a discrete term: if the Scholastics had articles, they
would surely have treated definite descriptions as discrete terms.
59
However, not every term which refers only to one thing is a discrete
term; in a world with only one man, the common term ‘man’ has only one
referent, but it is nonetheless common, since it is predicable of many. Only
those expressions which can be predicated of only one referent are discrete
terms as a matter of semantics, although other terms may as a matter of
fact e used to talk about only one referent. Criteria for distinguishing the
kinds of common supposition a term can have will depend on the relation of
the sentence in which the common term appears to sentences with discrete
terms. Common terms, of course, will be general referring expressions.
59
In general the Scholastics did distinguish descriptive knowledge from direct knowledge,
rather like Russell’s “knowledge by description” and “knowledge by acquaintance.” In
QM 7.20 fol. 54rb–va Buridan explores how names actually correspond to descriptions
(conjunctions of properties) in the absence of the thing named. See also Perreiah
[1972].
c Peter King, from Jean Buridan’s Logic (Dordrecht: D. Reidel 1985) 3–82.