I argue that the extant theories of self-deception face a counterexample which shows the essential role of instability in the face of attentive consciousness in characterising self-deception. I argue further that this poses a challenge to the interpretist approach to the mental. I consider two revisions of the interpretist approach which might be thought to deal with this challenge and outline why they are unsuccessful. The discussion reveals a more general difficulty for Interpretism. Principles of reasoning—in particular, the requirement of (...) total evidence—are given a weight in attentive consciousness which does not correspond to our reflective judgement of their weight. Successful interpretation does not involve ascribing beliefs and desires by reference to what a subject ought to believe and desire, contrary to what Interpretists suggest. (shrink)