We all have different "parts" of ourselves. We all know this intuitively. If we didn’t have different parts, we could never be in conflict with ourselves. No one would ever have failed at a diet, because there would only be one self, and that self wanted to be healthy. No one would ever procrastinate, because there would only be one self, and that self wanted to get stuff done. But of course we know that’s not true. Some part of me wants to be healthy, and some part wants to live on cookies and ice cream. Some part of me wants to get things done, and some part wants to binge watch my favourite show.