This introductory chapter argues that there are a number of different varieties of disjunctivism. But it is suggested that a mark of disjunctivism, in all of its varieties, is a refusal to credit a certain kind of significance to the fact that a pair of states can be indistinguishable from the subject's point of view. Three different varieties of disjunctivism about experience are introduced: experiential disjunctivism, according to which indistinguishable experiences can differ in intrinsic nature; epistemological disjunctivism, according to which indistinguishable experiences can differ in epistemic significance; and phenomenal disjunctivism, according to which indistinguishable experiences can differ in phenomenal character. A comparison is made with disjunctivism about bodily movement, and disjunctivism about reasons for acting. It is suggested that each variety of disjunctivism stands opposed to a Cartesian picture of the relation between the inner and the outer worlds.
Keywords: perception, action, knowledge, mind, epistemology, indistinguishability, experience, phenomenal character, bodily movement, reasons