Some Remarks on Second Order Logic with Existence Attributes
Nino B. Cocchiarella · Noûs · 1968
In Past, Present and Future A. N. Prior has suggested an approach towards the concept of existence where, following medieval logicians, we are to distinguish between predicates (like 'is red', 'is hard', etc.) which entail existence, and predicates (like 'is thought to be red', 'is thought of', etc.) which do not (p. 161). Let us refer to attributes (including relational attributes) which are designated by the former kind of predicate as existence attributes, or for brevity, e-attributes. It is suggested then that exists is to be defined as there is some e-attribute which x possesses. A formalization of this (at least) second order logic of existence was recently brought about and reported on by the present author in [6]. The formalization was shown to be complete in the sense corresponding to the completeness of standard second order logic, i.e., in the sense which encompasses normal, non-standard as well as standard models. (Cf. [1], ? 54). I should like in the present paper to discuss some of the philosophical issues involved in this formalization as well as some issues concerning the general notion of e-attribute.