Graham Priest

Curry’s paradox is well known. The original version employed a conditional connective, and is not forthcoming if the conditional does not satisfy contraction. A newer version uses a validity predicate, instead of a conditional, and is not forthcoming if validity does not satisfy structural contraction. But there is a variation of the paradox which uses “external validity”. And since external validity contracts, one might expect the appropriate version of the Curry paradox to be inescapable. In this paper we show that this is not the case. We consider two ways of formalising the notion of external validity, and show that in both of these the paradox is not forthcoming without the appropriate forms of contraction

To leave matters in no doubt, we obligingly assert that the Russell class R, i.e. {x : x 6∈ x}, both belongs to itself and also does not belong to itself; in short, we assert R ∈ R & ∼ . To be quite explicit, we assert the contradiction r & ∼ r, where r abbreviates R ∈ R. Thus, in convenient symbols, `δ r & ∼ r, where δ is the group of dialethicians comprising Priest and Routley. Now Goldstein asserts not, or not just, that we should not do what we have naughtily done, but that we cannot; it “is not that people should not assert contradictions, but that they cannot, even though they may purport to do so”

A crucial question here is what, exactly, the conditional in the naive truth/set comprehension principles is. In 'Logic of Paradox', I outlined two options. One is to take it to be the material conditional of the extensional paraconsistent logic LP. Call this "Strategy 1". LP is a relatively weak logic, however. In particular, the material conditional does not detach. The other strategy is to take it to be some detachable conditional. Call this "Strategy 2". The aim of the present essay is to investigate Stragey 1. It is not to advocate it. The work is simply an extended exploration of the strategy, its strengths, its weaknesses, and the various dierent ways in which it may be implemented. In the first part of the paper I will set up the appropriate background details. In the second, I will look at the strategy as it applies to the semantic paradoxes. In the third I will look at how it applies to the set-theoretic paradoxes.

‘What is philosophy?’ is a question that every professional philosopher must ask themself sometimes. In a sense, of course, they know: they spend much time doing it. But in another sense, the answer to the question is not at all obvious. In the same way, any person knows by acquaintance what breathing is; but this does not mean that they know the nature of breathing: its mechanism and function. The nature of breathing, in this sense, is now well understood; the nature of philosophy, by contrast, is still very much an open question. One of the reasons this is so is that the nature of philosophy is itself a philosophical question, so uncontentious answers are not to be expected—if philosophers ever ceased disagreeing with one another our profession would be done for. Moreover, it is a hard philosophical question. Many great philosophers, including Plato, Hegel, and others, have suggested answers to it. But their answers would now be given little credence. In the thirty or so years that I have been doing philosophy there have been two views about the nature of philosophy which have had wide acceptance. These are the views of the later Wittgenstein and of Derrida. In the first two parts of this paper I will describe these views and explain why I find them unsatisfactory. I will then go on, in the final part of paper, to outline a view that inspires more confidence in me

The view that everything is empty (śūnya) is a central metaphysical plank of Mahāyāna Buddhism. It has often been the focus of objections. Perhaps the most important of these is that it in effect entails a nihilism: nothing exists. This objection, in turn, is denied by Mahāyāna theorists, such as Nāgārjuna. One of the things that makes the debate difficult is that the precise import of the view that everything is empty is unclear. The object of this essay is to put the debate in a new light. It does so by proposing a mathematical characterization of Emptiness—that is, the totality of empty things—showing that, whatever it is, it has a definite structure and is not, therefore, to be identified with nothingness