Propositions occur in each other only as bases of a truth operation.

The general propositional form permits one proposition to contain another only as the basis of a truth operation, even though, at first sight, a different way seems possible.

In certain forms of proposition in psychology, such as 'A believes that p is the case' and 'A has the thought p', etc. it seems as if the proposition p stood in some kind of relation to an object A. In the event, however, 'A believes that p', 'A thinks p', and 'A says p' are actually the form 'p' says 'p'. This last is not an assignment of a fact to an object. Rather, facts are assigned to each other by assigning their objects to each other.

This also shows that the psyche - the subject, etc. - as conceived in Freud's psychoanalysis makes no sense. Namely, a composite soul would no longer be a soul.

The correct explanation of the form of the proposition, 'A concludes that p', must show that one cannot reach a conclusion that does not make sense. (Russell's theory does not satisfy this requirement.) To perceive a complex means to perceive that its constituents are related to one another in a particular way.

This, no doubt. also explains why there are two possible ways of seeing the figures in the drawings of M.C. Escher. We really do see two different facts. Each alternative perception of the drawing, though it is an illusion, is a fact. If I first perceive one and then the other, I have imagined two different images although all else has remained the same.