Peter Simons

Modal logic like many others sustains a hexagon of opposition, with the two “additional” vertices expressing contingency and non-contingency. We first illustrate hexagons of opposition generally by treating them as cut-down entailment lattices with order distinctions among multiple arguments suppressed. We then approach the modal case by treating it heuristically as a particular case of the hexagon for quantified propositions. Historically, possibility and contingency were sometimes confused: we show using the notion of duality that contingency, as negation-symmetric, is logically less interesting than possibility

[Peter Simons] Commonsense ontology contains both continuants and occurrents, but are continuants necessary? I argue that they are neither occurrents nor easily replaceable by them. The worst problem for continuants is the question in virtue of what a given continuant exists at a given time. For such truthmakers we must have recourse to occurrents, those vital to the continuant at that time. Continuants are, like abstract objects, invariants under equivalences over occurrents. But they are not abstract, and their being invariants enables us to infer both their lack of temporal parts and that non-invariant predications about them must be relativized to times. \\\ [Joseph Melia] In this paper I try to eliminate occurrents from our ontology. I argue against Simons' position that occurrents are needed to supply truthmakers for existential claims about continuants. Nevertheless, those who would eliminate occurrents still need some account of our willingness to assert sentences that logically entail their existence. Though it turns out to be impossible to paraphrase away our reference to occurrents, I show that the truthmakers for such sentences are facts that involve only continuants. This is enough to allow us to regard our ordinary talk about occurrents as fictional. Finally, I argue that a proper conception of the underlying temporal facts about continuants can both avoid the problematic tensed theory of time and the problem of temporary intrinsics

This book with an introduction by Witold Marciszewski, views the history of philosophy and logic from 1837 to 1939 from the perspective of the cradle of modern exact philosophy - Central Europe. In a series of case studies, it illuminates the developments in this region, most notably in Austria and Poland, examining thinkers such as Bolzano, Brentano, Meinong, Husserl, Twardowski, Lesniewski, and Tarski, as well as the logicians like Frege and Russell with whom they bore a close resemblance. The book challenges established views about the history of philosophy and logic in Europe, and shows the vitality of the Central European tradition.

Bolzano's theory of collections (Inbegriffe) has usually been taken as a rudimentary set theory. More recently, Frank Krickel has claimed it is a mereology. I find both interpretations wanting. Bolzano's theory is, as I show, extremely broad in scope; it is in fact a general theory of collective entities, including the concrete wholes of mereology, classes-as-many, and many empirical collections. By extending Bolzano's ideas to embrace the three factors of kind, components and mode of combination, one may develop a coherent general account of collections. But it is most difficult to take Bolzano's view to fit modern set theory. So while Krickel's positive thesis is rejected, his negative thesis is confirmed.

Gilbert Ryle wrote that "Meaning-theory expanded just when and just in so far as it was released from that 'Fido'-Fido box, the lid of which was never even lifted by Meinong". This paper sets out to relieve Ryle's oversimplification about Meinong and the role of meaning theory in his thought. One step away from canine simplicity about meaning is the recognition of a distinction between sense and reference, such as we find in Frege, Husserl, and the early Russell. In Über Möglichkeit und Wahrscheinlichkeit (1915) Meinong seems to corroborate Ryle when he writes, "Word-meanings are objects", but immediately after this, he qualifies it: "Word-meanings are very often auxiliary objects". The distinction between auxiliary and target objects in Meinong's later work allows us to attribute to him a theory of sense and reference which shows him to have indeed lifted the box-lid.

The philosophies of late Brentano and early Wittgenstein can be brought closer in two ways. One way discovers a surprising amount of part-whole theory in the Tractatus if we see states of affairs (not wholly wilfully) as thinglike rather than factlike. This throws up a modal analogue to Chisholm's entia successiva in the form of situations. The other way sees all propositions as truth-functions of existential propositions, supporting Brentano's view that existentials are primary, and incidentally yielding a reistic semantics for the Tractatus. I draw a quick moral, that we should beware of excessive simplicity in metaphysics, and apply it to Chisholm's views on part and whole.

In this chapter, I shall consider what the principal Austrian philosophers from Bolzano to Popper have had to say on the subject of truth. Since I shall cover a fair number of philosophers and theories, my considerations will be mainly confined to two linked questions: What – according to the philosopher in question – is the nature of truth? What ontology is required to explicate truth according to their account? Further questions concerned with our access to and knowledge of the truth will only be considered as necessary, since they lead into a tangle of issues for which I shall not have the space here. Neither shall I justify my selection of this or that philosopher as ‘Austrian’, but simply press on.

The relationship of part to whole is one of the most fundamental there is, yet until now there has been no full-length study of this concept. This book shows that mereology, the formal theory of part and whole, is essential to ontology. Peter Simons surveys and criticizes previous theories, especially the standard extensional view, and proposes a more adequate account which encompasses both temporal and modal considerations in detail. This has far-reaching consequences for our understanding of such classical philosophical concepts as identity, individual, class, substance and accident, matter, form, essence, dependence, and integral whole. It also enables the author to offer new solutions to long-standing problems surrounding these concepts, such as the Ship of Theseus Problem and the issue of mereological essentialism. The author shows by his use of formal techniques that classical philosophical problems are amenable to rigorous treatment, and the book represents a synthesis of issues and methods from the analytical tradition and from the older continental realist tradition of Brentano and the early Husserl.

George Boolos's employment of plurals to give an ontologically innocent interpretation of monadic higher‐order quantification continues and extends a minority tradition in thinking about quantification and ontological commitment. An especially prominent member of that tradition is Stanislaw Leśniewski, and shall first draw attention to this work and its relation to that of Boolos. Secondly I shall stand up briefly for plurals as logically respectable expressions, while noting their limitations in offering ontologically deflationary accounts of higher‐order quantification. Thirdly I shall focus on the key idea of ontological commitment and investigate its connection with the idea of truth‐making. Fourthly I shall consider how different interpretations of quantification may sideline Boolos's work, but finally I shall largely support his analysis of quantification involving nominal expressions, while arguing, in the spirit of Arthur Prior, that non‐nominal quantification is non‐committing