Handbook of the History of Logic: - Fordham University Faculty

174 Terence Parsons
The purpose of this section is to say how to expand the class of categorical propositions.
We need to say how to treat verbs other than the copula, and subjects
and predicates that are adjectives, or participles, or that are modified by relative
clauses, or that are possessives, and so on.
2.1 Adjectives
Aristotelian logic is awkward when applied to terms that are adjectives. If you
apply simple conversion to:
you get
Some donkey is grey
Some grey is [a] donkey
which is ungrammatical; a quantifier word like ‘some’ must combine with a noun,
not with an adjective. This problem has a solution in Latin, in which it is possible
to “substantivate” an adjective — which is to use it as a common noun with a
neuter gender. The sentence:
Every woman is tall
contains the adjective ‘tall’ which, in Latin, would bear a singular nominative
feminine inflection to agree with ‘woman’. But in this sentence:
Every tall is grey (meaning ‘Every tall thing is grey’.)
it is substantivated; it bears a singular nominative neuter inflection of its own,
and it is grammatically a noun. So it can be treated as part of the regimented
notation as already understood. (In this example ‘grey’ is still an adjective; it has
an adjectival inflection that agrees with the gender and number of ‘tall’.)
What does such a substantivated adjective supposit for? The obvious option is
that substantivated ‘tall’ supposits (with respect to a time) for each thing which
is tall (at that time). This is the common assumption, which is adopted here. 22
In ‘ Every tall is grey ‘ the ‘grey’ would not normally be substantivated; it would
remain an adjective with adjectival inflections. Presumably, it is here equivalent
to its substantivated version; it supposits (with respect to a time) for each thing
which is grey (at that time).
2.2 Extending the Theory to Intransitive Verbs
Having explained adjectives, there is a sense in which intransitive verbs have already
been accounted for. At least, the contents of these verbe already appear.
22 Buridan SD 8.2.4 (648): “‘white [thing]’ [album], amounts to, ‘white thing’ [res alba], or
‘white being’ [ens album].” In this quote ‘album’ is the substantivated version of ‘white’ and‘res
alba’ means literally ‘white thing’, wherein ‘white’ is an adjective.