Handbook of the History of Logic: - Fordham University Faculty

422 Gyula Klima
context, the conditions of their truth given in terms of the supposition of their
terms needs to be provided separately for different types of propositions:
Therefore, recapitulating, we put forth the fourteenth conclusion, namely
that every true particular affirmative is true because the subject and
predicate supposit for the same thing or things. And every true universal
affirmative is true because for whatever thing or things the subject
supposits for, the predicate supposits for that thing or for those same
things. And every false particular affirmative is false because the subject
and the predicate do not supposit for the same thing or things.
And every false universal affirmative is false because not every thing
or all things which the subject supposits for are also supposited for by
the predicate. And every true particular negative is true because the
universal affirmative contradictory to it is false; and we have declared
what the reason for this is. And every true universal negative is true
because the particular affirmative contradictory to it is false; and we
have declared what the reason for this is. And every false particular
negative is false because the universal affirmative contradictory to it is
true; and we have declared what the reason for this is. And every false
universal negative is false because the particular contradictory to it is
true; and we have declared what the reason for this is. 58
These clauses, in fact, may look very much like the clauses of the satisfaction
conditions of formulae in a formal semantics, serving a “definition of truth” (in a
model). Indeed, we may get the same impression from what Buridan says immediately
after these clauses:
And this fourteenth conclusion, which contains eight partial conclusions,
appears to be entirely true on the basis of the foregoing [points]
given the principle that whatever is the cause of truth of one of the
contradictories, or is required for its truth, is the cause of the falsity of
the other, or is required for its falsity. But in the end we should note
— since we can use names by convention, and many people commonly
use this way of putting the matter — that in respect of every true
proposition we say: ‘It is so’, and in respect of every false one we say:
‘It is not so’, and I do not intend to eliminate this way of speaking.
But for the sake of brevity I may use it often intending by it not what
it signifies on account of its primary imposition, but the diverse causes
of truth and falsity assigned above for diverse propositions, as has been
said. 59
58 Ibid. pp. 858-859.
59 Buridan will often refer back to this remark, reminding us that whenever he uses his simple
formula qualitercumque propositio significat ita est [‘In whatever way the proposition signifies
things to be, so things are’] or any of its stylistic variants, he uses it as a place-holder for the
conditions of the truth of the several types of propositions he laid down here. Note also how this
general formula is related to the colloquial phrase: A est B, necne? — Ita est. [literally: ‘A is