Abstract

This paper takes up David Kaplan's suggestion that the phenomenon of cognitive dynamics can be approached via a study of what it takes for someone to change her mind. It is argued that in order for a subject to be able to change her mind about something, there must be occasions on which the following is the case: (1) First, the subject believed of an 'x' that it was f, now she believes of 'x' that it is not-f. (2) She stopped believing of 'x' that it was f before she started believing of 'x' that it was not-f. (3) She knows that (1) and (2). The first part of the investigation shows why (1) - (3) are necessary within an account of what it is for someone to change her mind. The second part focuses on condition (3) and argues that it entails that the sameness or difference of thought content over time must sometimes be an epistemic given, i.e., that the subject can know that a thought she entertains now is the same as a thought she entertained earlier.