By reality we mean _persistence_ in consciousness: a persistence that is either unconditional, as our consciousness of space, or that is conditional, as our consciousness of a body while grasping it. The real, as we conceive it, is distinguished solely by the test of persistence; for by this test we separate it from what we call the unreal. Between a person standing before us, and the idea of such a person, we discriminate by our ability to expel the idea from consciousness, and our inability, while looking at him, to expel the person from consciousness. And when in doubt as to the validity or illusiveness of some impression made upon us in the dusk, we settle the matter by observing whether the impression persists on closer observation; and we predicate reality if the persistence is complete. How truly persistence is what we mean by reality, is shown in the fact that when, after criticism has proved that the real as we are conscious of it is not the objectively real, the indefinite notion which we form of the objectively real, is of something which persists absolutely, under all changes of mode, form, or appearance. And the fact that we cannot form even an indefinite notion of the absolutely real, except as the absolutely persistent, clearly implies that persistence is our ultimate test of the real as present to consciousness. Reality then, as we think it, being nothing more than persistence in consciousness, the result must be the same to us whether that which we perceive be the Unconditioned itself, or an effect invariably wrought on us by the Unconditioned. If some mode of the Unconditioned uniformly produces some mode of consciousness—if the mode of consciousness so produced, is as persistent as would be such mode of the Unconditioned were it immediately known; it follows that the reality will be to our consciousness as complete in the one case as in the other. Were the Unconditioned itself present in thought, it could but be persistent; and if instead of it, there is present its persistent effect, the resulting consciousness of reality must be exactly the same.