When you use the word “I” it designates you; when I use the same word, it designates me. If you use “you” talking to me, it designates me; when I use it talking to you, it designates you. “I” and “you” are indexicals. The designation of an indexical shifts from speaker to speaker, time to time, place to place. Different utterances of the same indexical designate different things, because what is designated depends not only on the meaning associated with the (...) expression, but also on facts about the utterance. An utterance of “I” designates the person who utters it; an utterance of “you” designates the person to whom it is addressed, an utterance of “here” designates the place at which the utterance is made, and so forth. Because indexicals shift their designation in this way, sentences containing indexicals can be used to say different things on different occasions. Suppose you say to me, “You are wrong and I am right about reference,” and I reply with the same sentence. We have used the same sentence, with the same meaning, but said quite different and incompatible things. (shrink)

Carnap's system of inductive logic has very often been criticized on the ground that “degree of confirmation” is defined only for languages which are extremely over-simplified. Allegedly, it would be very difficult—and perhaps impossible—to define it adequately for languages formalized within the higher predicate calculi, or languages equivalent to these in richness, and it is such languages that would be needed were we ever to formalize the language of empirical science as a whole. Thus, this criticism bears not only on (...) Carnap's work, but on all attempts to construct an exact analysis of induction from this particular standpoint; that is, from the standpoint of “logical measure functions.”. (shrink)

SCIENTISTS HAVE DISCOVERED that water is H2O. Water is H2O is true. But is it a necessary truth? In other words, is it true in all possible worlds? Some people think it is. For example Hilary Putnam, in his well-known Twin Earth argument, concludes that "water is H2O" is necessarily true; thus a liquid which phenomenally resembles H2O and fits the description of water in almost all aspects, but has the chemical formula XYZ, cannot be water. Saul Kripke has made (...) a similar claim about the necessary identity between water and H2O. Because this type of truth is based on empirical discoveries, Kripke calls truths of this sort "necessary a posteriori." The thesis shared by Putnam and Kripke has two premises: a realist view that natural kinds exist independently of human cognition, and a theory of direct reference of natural kind terms. Opposing the view that natural kind terms pick out objects through descriptions, Putnam and Kripke hold that natural kind terms pick out natural kinds in the world in a direct way. Based on these two premises, they argue that, if two natural kind terms, A and B, designate the same thing in the world, "A = B" expresses a necessary identity. (shrink)

Since Hume, philosophers of induction have debated the question of whether we have any reason for assuming that nature is uniform. This debate has always presumed that the uniformity hypothesis is itself coherent. In Part 1 of the following I argue that a proper appreciation of Nelson Goodman's so-called grue-green problem1 should lead us to the conclusion that the uniformity hypothesis, under its usual interpretation as a strictly ontological thesis, is incoherent. In Part 2 I argue that further consideration of (...) the grue-green problem leads to the conclusion that certain popular versions of the thesis of physical supervenience/the primacy of physics, under their usual interpretation as strictly ontological theses, are false. In Part 3 I argue that the notions of natural kinds and nature's joints should not be taken as ontologically objective notions but as interest relative. Together Parts 1, 2, and 3 provide support for the Nietzsche-Goodman thesis that philosophers are prone to mistakenly identify as absolute, mind and language independent, features of the world which are in fact only features of a particular discourse, or of the world relative to a particular discourse. (shrink)

Kripke has argued that definitions of units of measurements provide examples of statements that are both contingent and a priori. In this paper I argue that definitions of units of measurement are intended to be stipulations of what Kripke calls "theoretical identities": a stipulation that two terms will have the same rigid designation. Hence such a definition is both a priori and necessary. The necessity arises because such definitions appeal to natural kind properties only, which on Kripke's account are necessary.