And the various circumstances under which the mind does this give the occasions for the different names which the earlier psychology used for marking off different "faculties." These names are still convenient, however, and it may serve to make the subject clear, as well as to inform the reader of the meaning of these terms, to show how they all refer to this one kind of mental action.
The case of the orange illustrates what is usually called Perception.
It is the case in which the result is the knowledge of an actual object in the outside world.

When the same process goes on after the actual object has been removed it is Memory.

When it goes on again in a way which is not controlled by reference to such an outside object--usually it is a little fantastic, as in dreams or fancy, but often it is useful as being so well done as to anticipate what is really true in the outside world--then it is Imagination.

If it is actually untrue, but still believed in, we call it Illusion or Hallucination.

When it uses mere symbols, such as words, gestures, writing, etc., to stand for whole groups of things, it is Thinking or Reasoning.