Much work has been done on the formal analysis of attitudes like knowledge, belief and intention; e.g. [Halpern 1986, Cohen and Levesque 1990]. Much work has also been done on the application of non-monotonic logic to the problems of reasoning about change; e.g. [Brown 1987, Shoham 1988]. This paper brings together ideas from both fields to sketch a theory of changing attitudes. It takes the view that rational agents do not change their attitudes without reason, and aims to represent such changes in teleological theories. These can be regarded as extensions of Shoham’s causal theories. The infrastructure of teleological theories consists of persistence rules which state that an agent’s attitudes persist unless the agent has reason to change them. Teleological rules giving the agent’s reasons for changing their attitudes build on these. We illustrate with beliefs, goals and intentions, and suggest the extension to other attitudes.