J.D. Collier sees Putnam as arguing that metaphysical realism is false.' He sees the argument as proceeding from the background assumption that metaphysical realism has the consequence that truth is 'radically non-epistemic', so that 'an [epistemically] ideal theory could be radically wrong about the world' [3, p. 413]. But, according to Collier, Putnam argues that 'an ideal theory satisfying all of our methodological and theoretical constraints cannot be false' [3, p. 413]. Collier attempts to defend metaphysical realism against this Putnamian (...) attack by distinguishing 'between our ability to state a theory and our ability to conceive its possibility' [3, p. 413]. I will show that this defence is unsuccessful. (shrink)

The argument that has inspired much of the recent discussion of the logical relationship between these views is found in Putnam : If externalism is true, then if S were a brain in a vat, S’s utterances of the sentence “I am a brain in a vat” would not express the proposition that S is a brain in a vat. S’s use of the words “brain” and “vat” would not refer to a real brain or vat, just as, in a (...) Twin Earth-style thought experiment, the Twin Earthling cannot refer to water with his use of the term “water.” If we accept that generally we have knowledge of the contents of our utterances, then, if S knows that her utterances of “brain” and “vat” mean brain and vat, it will be possible for S to know that she is not a brain in a vat. For if S has authority with respect to the contents of her utterances, then she can know that her utterance, “I am not a brain in a vat,” refers to brains and vats. On externalism, since S would not refer to brains and vats if she were a brain in a vat, she could know by mere introspection that she is not a brain in a vat. In fact, S can come to know many arbitrary propositions about the external world simply by attending to the contents of her thoughts. For if externalism is true, she can argue, then certain empirical conditions must be satisfied if she is even to have the thoughts about the external world that she does; since she knows what she is thinking, she knows these empirical conditions are satisfied. Thus, if S knows that she is thinking about brains and vats, then she can know that she is not a brain in a vat ; for if she was a BIV, then she would not be thinking about brains and vats, but instead about electrical impulses or some such thing. The standard BIV argument against scepticism, therefore, cannot be correct. This line of argument can then be used to conclude more generally that scepticism is false; for the argument can be run with virtually any utterance or thought with empirical content. If S knows that she is thinking about trees, for example, then she can know that there are trees. (shrink)

This chapter presents a detailed explanation of Peirce’s early and late views on semiotic indeterminacy and then considers how those views might be applied within biosemiotics. Peirce distinguished two different forms of semiotic indeterminacy: generality and vagueness. He defined each in terms of the “right” that indeterminate signs extend, either to their interpreters in the case of generality or to their utterers in the case of vagueness, to further determine their meaning. On Peirce’s view, no sign is absolutely determinate, i.e., (...) every sign is indeterminate to at least some degree and so exhibits some degree of generality or vagueness. If Peirce was right about this, then no instance of biosemiosis is completely determinate—every biosign must be general or vague to some degree. I show that on Peirce’s view, whether a sign is general or vague depends on its immediate object, “the idea which the sign is built upon,” and I explain how Peirce would go about identifying the immediate object of a sign lacking both a minded utterer and a minded interpreter—an identification that must be possible if any biosign is indeterminate. (shrink)