This chapter provides a much more rigorous account on the problems of self-deception. It introduces some of the major moves, both historically and theoretically, in response to these problems. The chapter discusses further diagnostic questions or decision points for characterizing self-deception, and this etches a way to developing a conceptual map for charting theories of self-deception and the psychological space of motivated irrationality. It considers the “Basic Problem” of self-deception: The Basic Problem: The Basic Problem of self-deception is to show the compatibility and actuality of three key elements of self-deception: real deceptive measures taken against, a single self, and with some success at this deceptive enterprise. The concept of self-deception is fuzzy, as is almost every philosophically interesting concept. Multiple paths through the conceptual space might warrant the label “self-deception. The self-deceived might be described as having mixed thoughts.