Programme

Kant presents his conception of existence primarily in the context of his refutation of the ontological argument for the existence of God. Studying the latter reveals the subtilities of Kant’s theses on what existence is and is not, and the arguments that he offers for these theses.  The two canonical texts in which Kant lays out his refutation are the precritical essay Only Possible Argument [OPA] (1763) and the ‘Ideal of Pure Reason’ of the Critique of Pure Reason [CPR] (1781/1787). One prevalent trend in the literature is to view the refutation that Kant presents in the CPR as a mere restatement of his objection in the OPA. While there is substantial continuity between the two texts, especially regarding Kant’s views on existence, Kant’s treatment of the ontological argument in the CPR cannot be reduced to a restatement of that in the OPA. For in the OPA, Kant adopts a single line of objection, which purports to block the argument’s introduction of existence into the concept of God by invoking his well-known thesis that existence is not a predicate. This line of objection is historically Kant’s own invention and he presents it as obviously damning to all previous versions of the ontological argument, without any specific engagement with the logical mechanics of those. In the CPR, on the other hand, Kant offers a detailed systematic refutation, based on a multilayered, dialectical strategy, aiming to cover both the classical (Anselm, Descartes) and modal (Anselm, Leibniz, Wolff, Baumgarten) versions of the argument with a number of subtle arguments, all but one of which are usually understudied in the literature because of the aforementioned reductionist trend. And most importantly, Kant’s refutation in the CPR employs a conception of modality that is distinctively critical. 

In this paper I aim to show four things. Firstly, that Kant’s view of existence belongs to an act-theoretic tradition of view of being and not to the same tradition as the views of Frege and Russell. Secondly, Kant conceives existence as a mode of positing, as a non-conceptual constituent of certain judgements. Thirdly, I will distinguish three different traditions of conceiving Kant’s conception of existence: the act-theoretic, the epistemic and the predicative tradition. Finally, I am to show that the founder of the predicative tradition is Ernst Reinhold, and that Bolzano, Sigwart, Frege and Schröder followed his lead at least conceptually.

Bolzano and Frege advocate a twofold conception of existence: they distinguish between the concept expressed by the quantifier "there is" and the concept expressed by the predicate "exists". However, whereas Frege understands "exists" as a predicate applying to anything there is, Bolzano takes it to be applicable only to objects that are part of the causal order. Since this is a merely verbal difference, I will focus on "there is". Both Bolzano and Frege argue for a higher-order conception according to which there-is-sentences correspond to sentences stating that a concept is satisfied, and both claim that there-is sentences are synonymous with syllogistic particulars. They differ, however, in their treatment of singular there-is sentences. While Frege argues that they are meaningless, Bolzano assumes that there are no essential difference between them and their general counterparts. I will both criticise Frege's and Bolzano's justifications for their claims. Moreover, I will point out why Bolzano is reluctant when it comes to the question whether there-is sentences are not only equivalent to the corresponding higher-order sentences but also synonymous with them. In my view, he thereby hints at a problem affecting higher-order conceptions in general.

This paper is about the theory of existence of Anton Marty. For Marty, existence is a first-order property, that of correct-acknowledgeability. An acknowledgment is an affirmative judgment, that is, the positing of an object. Thus, existence is the correlative property, in the object, of a possible correct positing. This notion of existence is initially found in Marty’s master Franz Brentano. Marty develops and defends Brentano’s view against competing theories of existence of other German-speaking philosophers. In particular, he opposes Sigwart’s theory that existence is the correspondence of the content of a representation with a perceivable object. Marty criticizes this view for making of existence the property of a concept and thus a higher-order property. He also criticizes Bolzano, Husserl and Meinong for accepting different modes of being in addition to existence, such as “subsistence” or “ideal being”. He rejects these views in claiming that being and existence are the same and that being is univocal. In this expository paper, I present Marty’s theory of existence and his debates with his fellow German-speaking philosophers.

Starting with Russell's Principles of Mathematics (1903), I trace the main developments in his treatment of existence until Introduction to Mathematical Philosophy (1919). I show that the idea that existence is a property of propositional functions, with which he is often associated, did not arrive in his philosophy with the theory of descriptions. To the contrary, this idea is not even a clear part of his writing around the time of Principia Mathematica. I also argue that his treatment of existence in the years 1910-1914 was, unbeknownst to him, inconsistent with his theory of acquaintance.

It has been said of Frege that he 'introduced and brilliantly exploited second-order variables ranging over concepts' so that contemporary higher order logic 'is a good model' of his logicist system. Quine has been a fierce critic of second-order logic and has consistently advocated restricting quantification to first-order variables. Second-order variables are commonly taken to range over concepts, properties, relations, or functions and from early in his career, Quine deemed these to be 'abstract entities' of dubious scientific value. In this paper I ask, do Quine's objections to second-order quantification engage with Frege? I argue that they do not. Quine fails to differentiate, within the notion of meaning, Fregean concepts–– which are not objects––from objects, the referents of singular terms. Nor does he recognize the difference between the concept/object distinction and that between the sense of an expression and what is indicated by it. He has in his sights Carnapian 'intensions,' which confusedly merge Frege's concept/object and sense/indication (reference) distinctions. Because he does not engage with Frege's actual semantics, Quine's objections to Frege's second-order quantifiers fail. Moreover, it is argued, once looked at in a Fregean light, Quine's account of quantification turns out to be seriously confused. 

Gilbert Ryle famously held that “exists” is not a univocal term, that (for example), “exists” in “there exist minds” and “there exists bodies” has different senses. This view has been subjected to strong criticism by (among others) Quine and van Inwagen. In this talk I return to the roots of Ryle’s view in the theory of logical types of Principia Mathematica, the progenitor of Ryle’s conception of categories, and the associated doctrine of “typical ambiguity” or “systematic ambiguity,” specifically as it applies to existence treated as a higher-order concept. I discuss Ryle’s appropriation of this terminology both from Russell and Whitehead’s  and from Susan Stebbing’s 1930 A Modern Introduction to Logic, in his 1945 paper “Philosophical Arguments” and explain how it is at the root of his thesis of the equivocity of existence. I explain how this entails that for Ryle treating existence as univocal when applied as a higher-order concept to different categories must lead to absurdities that reveal a category mistake. I assess the prospects of such a view in the light of the arguments of Quine and van Inwagen.

All higher-order existence that we know assume that existence is a property of general concept. In this paper, we aim to defend an alternative to this view that assumes that existence is a property of the extension of individual concepts. We will argue that some individual concepts track objects across all possible worlds and are, hence, rigid, while other are non-rigid individual concepts aim to identify certain individual objects. We will provide a detailed motivation for this view and formal semantic of existential sentences on this basis. Finally, we will show how the formal framework can be extended to distinguish, existence-entailing, non-existence-entailing and existential neutral predicates