Frederick Kroon

EXISTENTIALISM IN PHILOSOPHICAL LOGIC IS THE DOCTRINE THAT STATES OF AFFAIRS, PROPOSITIONS AND PROPERTIES INVOLVING OBJECTS INCLUDE THESE OBJECTS AS DIRECT CONSTITUENTS IN AT LEAST THE SENSE THAT THE NONEXISTENCE IN A WORLD w OF SOCRATES, SAY, IMPLIES THE NONEXISTENCE IN w OF SOCRATES' BEING SNUB-NOSED. JOHN POLLOCK HAS RECENTLY ARGUED (IN "THE FOUNDATIONS OF PHILOSOPHICAL SEMANTICS") THAT SUCH AN EXISTENTIALISM HARBOURS AN INCONSISTENCY. THE PRESENT PAPER REBUTS POLLOCK'S ARGUMENT BY ARGUING THAT IT DEPENDS ON A CHARACTERIZATION OF EXISTENTIALISM THAT EXISTENTIALISTS HAVE NO REASON TO ACCEPT, AND, INDEED, GOOD REASON TO REJECT

This paper deals with a philosophical question that arises within the theory of computational complexity: how to understand the notion of INTRINSIC complexity or difficulty, as opposed to notions of difficulty that depend on the particular computational model used. The paper uses ideas from Blum's abstract approach to complexity theory to develop an extensional approach to this question. Among other things, it shows how such an approach gives detailed confirmation of the view that subrecursive hierarchies tend to rank functions in terms of their intrinsic, and not just their model-dependent, difficulty, and it shows how the approach allows us to model the idea that intrinsic difficulty is a fuzzy concept.

Let g E(m, n)=o mean that n is the Gödel-number of the shortest derivation from E of an equation of the form (m)=k. Hao Wang suggests that the condition for general recursiveness mn(g E(m, n)=o) can be proved constructively if one can find a speedfunction s s, with s(m) bounding the number of steps for getting a value of (m), such that mn s(m) s.t. g E(m, n)=o. This idea, he thinks, yields a constructivist notion of an effectively computable function, one that doesn't get us into a vicious circle since we intuitively know, to begin with, that certain proofs are constructive and certain functions effectively computable. This paper gives a broad possibility proof for the existence of such classes of effectively computable functions, with Wang's idea of effective computability generalized along a number of dimensions.

This paper begins with a puzzle about certain temporal expressions: phrases like ‘Jones as he was ten years ago’ and ‘the Jones of ten years ago’. There are reasons to take these as substantival, to be interpreted as terms for temporal parts. But it seems that the same reifying strategy would also force us to countenance a host of less attractive posits, among them fictional counterparts of real things (to correspond to such phrases as ‘Garrison as he was in the movie JFK’) and much more. I argue that there is a better way: we need only the idea of pretense or make-believe to make sense of claims embedding such phrases, leaving us with no reason, so far, to accept an ontology of temporal parts.

I'll begin this paper with an autobiographical example — an instance of a common enough kind of case involving agents who are faced with making a choice they strongly care about, but who have tendencies that incline them towards choosing an option they prefer not to choose. Later in the paper, I apply some of the general lessons learned from this case to a philosophically more familiar example of a hard-to-make choice, and to the well-known problem the example generates for the idea of rational agency: Gregory Kavka's toxin puzzle.Some time ago I did a bungy jump. Nothing remarkable in that.

Kant's distinction between things in themselves and things as they appear, or appearances, is commonly attacked on the ground that it delivers a radical and incoherent ‘two world’ picture of what there is. I attempt to deflect this attack by questioning these terms of dismissal. Distinctions of the kind Kant draws on are in fact legion, and they make perfectly good sense. The way to make sense of them, however, is not by buying into a profligate ontology but by using some rather different tools – surprisingly enough, tools first developed in the area of aesthetics. Once this is done, much of what Kant says begins to look perfectly coherent. In the final part of the paper, I point out that none the less all is not well. Kant's Critical doctrines make it hard for us to accept Kant's own version of this otherwise coherent distinction.

This paper suggests that quantified negative existentials about fiction—statements of the form “There are some / many / etc. Fs in work W who don't exist”—offer a serious challenge to the theorist of fiction: more serious, in a number of ways, that singular negative existentials. I argue that the temptation to think that only a realist semantics of such statements is plausible should be resisted. There are numerous quantified negative existentials found in other areas that seem equally “true” but where a realist semantics imports ontological commitments that few would want to embrace. In the final part of the paper I sketch an alternative pretense account of one such quantified negative existential, and suggest that the account gives us some reason to believe that quantified negative existentials in general, including quantified negative existentials about fiction, can also be understood in pretense terms.

Consider predicates like 'is a fictional character' and 'is a mythical object'. Since their ascription entails a corresponding Negative Existential claim, call these 'NE-characterizing predicates'. Objectualists such as Parsons, Sylvan, van Inwagen, and Zalta think that NE-characterizing properties are genuine properties of genuinely non-existent objects. But how, then, to make room for statements like 'Vulcan is a failed posit' and 'that little green man is a trick of the light'? The predicates involved seem equally NE-characterizing yet on the surface fail to mark a genuine property o f things. Instead, the truth of such predications strongly supervenes on types of referential failure. Kendall Walton's anti-objectualist account of talk about fiction provides a neat solution to this supervenience problem by invoking special games of make-believe. The present paper claims that while Walton's view thereby gains an important advantage over objectualism, the solution faces problems of its own. The rest of the paper desribes another solution, one that assigns a large role to the idea of metaphor.