This paper explores the idea of disagreement with oneself, in both its diachronic and synchronic forms. A puzzling case of synchronic intrapersonal disagreement is presented and the paper considers its implications. One is that belief is a genus that comes in two species: as disposition and as commitment. Another is that self-deception consists in a conflict between one's beliefs as dispositions and one's beliefs as commitments. Synchronic intrapersonal disagreement also has implications for the condition that needs to be fulfilled in order to have genuine disagreement tout court, and for the different ways in which it can be satisfied.