A version of the POSIWID principle is known by the Latin tag Cui Bono: Who benefits?
Galbraith's concept of Innocent Fraud is an excellent example of this. It denotes action that benefits the actor without the actor being consciously aware of this. The purpose of your actions can be inferred from how you benefit from your actions, even if this is not consciously planned. Following Freud, we know that we are driven by mechanisms of which we know nothing and often prefer to remain ignorant.
This is why political sincerity is so dangerous. A politician (for example one with a background as a lawyer, perhaps you can guess the one I mean) can convince himself that a given position is morally and intellectually sound; it is possible that his outrage and hurt when he is challenged on this position is quite genuine.
Update: I 0riginally wrote "Qui Bono" and I've been meaning to correct this for ages. Sorry about this.