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.