There is an argument which seems to show that if all truths are knowable then all truths are known. It may be viewed as a "reductio ad absurdum" of certain forms of antirealism. However, The claim has been made elsewhere that the argument fails against antirealists who employ constructivist rather than classical logic. The paper defends and amplifies this claim against criticisms by crispin wright and others. Relations between knowability and time are discussed. Suggestions are also made about the proper (...) form of the constructivist semantics for the conditional, Involving a non-Platonistic version of the distinction between types and tokens of proofs. (shrink)

If anti-realism is defined as the principle that all truths are knowable, then anti-realists have a reason to revise logic. For an argument first published by Fitch seems to reduce anti-realism to absurdity within classical but not constructivist logic. One might try to sever this link between anti-realism and revisionism in logic by giving either a modified version of anti-realism not vulnerable to Fitch's argument within classical logic or a modified version of Fitch's argument to which anti-realism is vulnerable within (...) constructivist logic. (shrink)

Perennial philosophers' hopes are unlikely victims of swift, natural deduction. Yet anti-realism has been thought one. Not hoping for anti-realism myself I here show it, lest it be underestimated, to survive the following argument, adapted from W. D.Hart pp. 156, 164-5; he credits first publication to Fitch).

Perry argues that certain sorts of indexicals are 'essential', in the sense that they cannot be eliminated in favor of descriptions. This paper also introduces the influential idea that certain sorts of indexicals play a special role in thought, and have a special connection to action.

This paper is in three sections. In the first I describe and illustrate three uses of indices of truth in semantics. The way I illustrate this classification is not completely uncontroversial, but I expect that my intuitions on this matter are generally shared. In the second section I broach a question which is central to the metaphysics of time, namely: how should certain temporal indices of truth - times - be fitted within this classificatory scheme? I sketch three proposals as (...) to how this might be done, and show how they constitute different metaphysical conceptions of the nature of time. Finally, in the third section I turn to a specific problem with the classification of times (as indices of truth) I call 'non-indexical'. Mellor (1981) thinks this problem insoluble, and argues that it shows this classification to be absurd. However, by appealing to the modal analogues of the issues involved, I first show that Mellor's argument is question- begging, and then go on to show how the non-indexical classification of times might undermine the presuppositions on which his argument rests. The paper attempts to contribute to a discussion of the question raised in section II, not to provide a definitive answer to it. (shrink)

This highly acclaimed book is a major contribution to the philosophy of language as well as a systematic interpretation of Frege, indisputably the father of ...

This is a study of the nature of time. In it, redeploying an argument first presented by McTaggart, the author argues that although time itself is real, tense is not. He accounts for the appearance of the reality of tense - our sense of the passage of time, and the fact that our experience occurs in the present - by showing how time is indispensable as a condition of action. Time itself is further analysed, and Dr Mellor gives answers to (...) most of the metaphysical questions it provokes, concerning the relation of time to space, the dissection of time, and its relation to change and causation. (shrink)