Eli Hirsch

This is a strikingly original, rich, and trenchant study. Its point of departure is the notion of discrimination, which is shown to illuminate a range of topics in metaphysics and epistemology, including subjectivity, observationality, sorites paradoxes, and identity criteria. A central problem involves the phenomenal character of experience. We are intuitively tempted to say that character is subjective in the sense that distinct characters must be discriminable. This seems to imply that matching experiences--that is, experiences which are indiscriminable in character--must have the same character. We find familiar cases, however, in which the experiences x and y match, and the experiences y and z match, but x and z do not match. Williamson defends the subjectivity of character by arguing that a pair of characters may be indiscriminable as presented by one pair of experiences but discriminable as presented by another pair of experiences. Hence the indiscriminability of characters is indeed sufficient for their identity, which makes characters subjective, but the matching of experiences is not sufficient for the experiences' having the same character.