Bredo Johnsen

Christopher Peacocke has recently made an important and insightful effort to fashion a non-verificationist method for distinguishing sense from nonsense. The argument is subtle and complex, and varies somewhat with each of his three target ‘spurious hypotheses’: that if a perfect fission of one person into two were to occur, one and only one of the resulting persons would be identical with the original; that another person’s visual experience can be qualitatively different from your own when you are both seeing the same object, even though your relevant brain states are physically identical and so are your environmental conditions; and that the entire material universe is moving undetectably at a particular uniform velocity with respect to absolute space. My own assessment of his efforts is that they are most successful against the third of these hypotheses, and that this is a function of the fact that of the three, it alone clearly employs a problematic concept- that of absolute location. However, my purpose here is not to engage in a comprehensive evaluation of Peacocke’s project; it is rather to defend the extreme inverted spectrum hypothesis against his attack. I shall argue not only that his argument against EISH fails, but that he is himself independently committed to its intelligibility. Beyond that, I shall point out some striking and, to my mind, welcome consequences of his plausible claims concerning the relations between his own proposal and certain other views concerning content theory; the consequences in question depend both on his positive proposal and on my reasons for rejecting his argument against the extreme inversion hypothesis.

In several recent writings and in the 1980 Freemantle Lectures at Oxford, Alvin Plantinga has defended the idea that belief in God is ‘properly basic,’ by which he means that it is perfectly rational to hold such a belief without basing it on any other beliefs. The defense falls naturally into two broad parts: a positive argument for the rationality of such beliefs, and a rebuttal of the charge that if such a positive argument ‘succeeds,’ then a parallel argument will ‘succeed’ equally well in showing that belief in the Great Pumpkin is properly basic. In this essay I shall argue both that Plantinga has partially misconceived the objection, and that he has not succeeded, indeed cannot succeed, in rebutting it, for the objection does in fact constitute a reductio ad absurdum of his position. For the sake of ease of exposition, I shall first provide a bare sketch of the positive argument, though I shall discuss it directly only as it bears on the attempted reductio.

In ‘Skeptism Oisarmed,’ L.S. Carrier asserts the following:… any reasonable person would accept premise only on the ground that both p and q are propositions for which we can get the requisite evidence.Premise, actually a premise schema attributed to Peter Unger, is the following:If A both knows p and knows that p entails q, then A can come to know that q.I suggest, contrary to Carrier's assertion, that many reasonable people, including many philosophers, would regard as a necessary truth knowable a priori, and would be quite happy to accept its universal quantification, with no implied restriction to propositions for which we can get any evidence at all.How is such a dispute about what reasonable people would do to be resolved? I suggest that, at the very least, Carrier owes us an explanation of the grounds on which he would reject particular instances of the schema, e.g.