What I have here called belief may be roughly distinguished into simple and compound belief.  By a simple belief I mean one which has to do with a single event or fact.  It includes simple modes of expectation, as well as beliefs in single past facts not guaranteed by memory.  A compound belief, on the other hand, has reference to a number of events or facts.  Thus, our belief in the continued existence of a particular object, as well as our convictions respecting groups or classes of events, must be regarded as compound, since they can be shown to include a number of simple beliefs.

A. Simple Illusory Belief:  Expectation.

It will be well to begin our inquiry by examining the errors connected with simple expectations, so far as these come under our definition of illusion.  And here, following our usual practice, we may set out with a very brief account of the nature of the intellectual process in its correct form.  For this purpose we shall do well to take a complete or definite anticipation of an event as our type.[136]

The ability of the mind to move forward, forecasting an order of events in time, is clearly very similar to its power of recalling events.  Each depends on the capability of imagination to represent a sequence of events or experiences.  The difference between the two processes is that in anticipation the imagination setting out from the present traces the succession of experiences in their actual order, and not in the reverse order.  It would thus appear to be a more natural and easy process than recollection, and observation bears out this conclusion.  Any object present to perception which is associated with antecedents and consequents with the same degree of cohesion, calls up its consequents rather than its antecedents.  The spectacle of the rising of the sun carries the mind much more forcibly forwards to the advancing morning than backwards to the receding night.  And there is good reason to suppose that in the order of mental development the power of distinctly expecting an event precedes that of distinctly recollecting one.  Thus, in the case of the infant mind, as of the animal intelligence, the presence of signs of coming events, as the preparation of food, seems to excite distinct and vivid expectation.[137]

As a mode of assurance, expectation is clearly marked off from memory, and is not explainable by means of this.  It is a fundamentally distinct kind of conviction.  So far as we are capable of analyzing it, we may say that its peculiarity is its essentially active character.  To expect a thing is to have stirred the active impulses, including the powers of attention; it is to be on the alert for it, to have the attention already focussed for it, and to begin to rehearse the actions which the actual happening of the event—­for example, the approach of a welcome object—­would excite.  It thus stands in marked contrast to memory, which is a passive attitude of mind, becoming active only when it gives rise to the expectation of a recurrence of the event.[138]