2. MENTAL LANGUAGE AS AN IDEAL LANGUAGE
5
tal Language are like functions that take concepts into expressions, some
sensitive to order, others not. These “functions,” or logical operations in
Mental Language, are themselves concepts; Buridan calls them complexive.
Their role is to combine concepts into new complex concepts; they are thus
term-forming or sentence-forming functors.
7
Now Buridan’s distinction between syncategorematic and categorematic
terms, roughly parallel to the modern distinction between logical and non-
logical particles, is explained by complexive and non-complexive concepts
respectively.
8
Pure syncategorematic terms lack an ultimate signification,
but they do not lack all signification: they are or immediately signify com-
plexive concepts, and they have an ultimate signification only in combi-
nation with categorematic terms. Pure categorematic terms, on the other
hand, have an ultimate signification, and they are or immediately signify
non-complexive concepts.
9
Only such logical considerations as precedence,
order, scope, and the like are relevant to the individuation of expressions
in Mental Language. Furthermore, such considerations are self-intimating,
since Mental Language is the language of thought; we cannot help but be
aware of scope distinctions and the like. Therefore, it is logically perspicu-
ous.
Given (i )–(v ), Buridan’s Mental Language has been thought to be much
like the ‘logically ideal languages’ in vogue at the beginning of the past
century. Such ideal languages have been put to various uses by various
philosophers: Carnap for the logical reconstruction of the world, Wittgen-
stein to show what can be said and what cannot, Russell and Quine for
uncovering (or avoiding) ontological commitment. Buridan’s use of Mental
7
SDD 4.2.3 20.4–8: “Et etiam illae copulae est et non est significant diuersos modos
complectendi terminos mentales in formando propositiones mentales, et illi modi com-
plectendi sunt conceptus complexiui pertinentes ad secundam operationem intellectus,
prout ipsa addit supra primam operationem. Et ita etiam istae dictiones et, uel, si,
ergo et huiusmodi designant conceptus complexiuos plurium propositionum simul uel
terminorum in mente et nihil ulterius ad extra.” See also QLP 1.7 33.23–24.
8
Modern logicians take the difference between logical and non-logical terms as primitive,
such that the logical constants are listed separately and appear in the syntactical
rules in special ways. Buridan, however, distinguishes logical and non-logical terms
semantically, by their signification.
9
There are ‘mixed’ cases in spoken and written languages that are neither purely syn-
categorematic nor purely categorematic (SDD 4.2.3); they immediately signify some
complex combination of complexive and non-complexive concepts. For our purposes
we may ignore them, though Buridan does think that the identification and analysis
of such mixed terms is at the heart of the logician’s activity, as he says in SDD 1.2.2:
“Nec etiam credendum est quod logicus a sua consideratione debeat excludere syn-
categoremata; immo ex eis sunt in logica quasi omnes difficultates.”
c Peter King, unpublished
6
BETWEEN LOGIC AND PSYCHOLOGY
Language, it has been maintained, is closest to the Russell-Quine approach:
it is a case of semantics in the service of ontology. To see how this can be,
we have to examine two other semantic relations.
3. Supposition, Definition, and Appellation
It’s one thing to correlate terms with their significates so that a lan-
guage may be established in the first place; that is done by signification.
It’s another thing to actually use the terms to talk about their significates,
which is a distinct semantic relation that obtains between terms and their
significates. This latter semantic relation is called ‘supposition,’ which ac-
counts for the referential use of categorematic terms. Hence signification
and supposition differ in two ways. First, terms retain their signification at
all times, but it is only in a sentence that terms are used referentially, that
is, to talk about things and say something about them. Thus a term has
supposition only in a sentential context. Second, we do not always use terms
to talk about everything those terms ultimately signify; we mention, as well
as use, terms, and sometimes we speak only of a subclass of all a term’s
significates. Thus a term may have different kinds of supposition depend-
ing upon its sentential context. Buridan identifies two varieties: personal
supposition, which occurs when a term stands for what it ultimately sig-
nifies, and material supposition, which occurs when a term does not stand
for what it ultimately signifies.
10
Hence the term ‘Socrates’ in the sen-
tence “Socrates is human” has personal supposition, referring to Socrates
himself, whereas in “Socrates is a three-syllable word” it has material sup-
position, referring to the utterance ‘Socrates.’ (Note that it is still the same
term in each sentence.) Much as signification is the mediæval correlate to
a theory of meaning, supposition is the mediæval correlate to a theory of
reference—and, like any theory of reference, is the guide to ontology. We
can uncover the ontological commitments of a theory by discovering which
terms appearing referentially in the (mental) sentences of the theory are
10
More exactly: 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 to a sentence presupposing
an existential sentence, to produce a true sentence. The demonstrative pronoun and
the copula of (i ) and (ii ) should be taken in the appropriate tense, grammatical
number, and mood. This definition is a generalization of the account of personal
supposition Buridan sketches in SDD 4.1.2 10.8–10: “Vel possumus dicere quod ad
hoc quod terminus possit supponere, sufficit quod uere possit affirmari uel de tali
pronomine uel de relatiuo referente aliquem terminum priorem.” A term has material
supposition at all other times, e. g. when an inscription such as ‘Socrates’ supposits
for the inscription or for the concept of Socrates rather than for Socrates himself.
c Peter King, unpublished