Quodlibeta talk: Ways of not existing: the postulation of esse essentiae in some medieval sophisms

The next Quodlibet will be given by Ernesto Perini-Santos (Federal University of Minas Gerais and University of Geneva). The talk will be followed by a wine reception at Uni Bastions near B108.

Abstract:

Ways of not existing: the postulation of esse essentiae in some medieval sophisms

What sorts of truth, if any, are there about the non-existent? Meinong’s Independence Principle says that there is no constraint whatsoever: that an item has properties does not require its existence. On a reductionist approach, truths about the non-existent have to be explained in terms of truths about the existent. At least in a certain medieval literature, there is a constraint on truths about the non-existent, but not a reductionist constraint. The only sort of truth about the non-existent are essential predications. This is the case of

i. homo est animal,
when no man exists. There are two ways the explain the truth of (i). In one account, this sentence is true because there is a necessary relation between the concepts of man and of animal. Another explanation is that essential predicates are true of a peculiar kind of being,esse essentiae. As it should be expected in medieval semantics, truth is cashed out in terms of supposition: in (i), homo has supposita essentialia, that is, it supposits both for existing and non existing men. Therefore, the sentence

ii. Caesar est homo
is true, even if Cesar is dead. However, from (ii) we cannot infer

iii. Caesar est.
We cannot say either (no matter how Cesar was hair-wise)

iv. Caesar est calvus,
for it is an accidental predication.
This step beyond being cannot be explained in terms of ampliative contexts, such as past- and future-tense verbs, nor of intensional expressions, such as ‘imaginable’. At least in this sort of literature, there is no medieval Meinongian object. This extension of being had the limited purpose of explaining necessary truths about a contingent world, unlike the all-purpose Meinongian theory of objects.