For Perry and many authors, de se thoughts are a species of de re thought. In this paper, I argue that de se thoughts come in two varieties : explicit and implicit. While explicit de se thoughts can be construed as a variety of de re thought, implicit de se thoughts cannot : their content is thetic, while the content of de re thoughts is categoric. The notion of an implicit de se thought is claimed to play a central role in accounting for the phenomenon of immunity to error through misidentification. Lewis has attempted to unify de re and de se in the opposite direction : by reducing de re to de se. This, however, works only if we internalize the acquaintance relations. I criticize Lewis's internalization strategy on the grounds that it res...