These difficulties are so fundamental and so obvious, that the theory of the phenomenal nature of human knowledge, which, being interpreted, means that we know nothing, could scarcely maintain its hold, were it not confused with another fact of human experience, that is apparently inconsistent with the doctrine that man can know the truth.  Side by side with the faith of ordinary consciousness, that in order to know anything we must think, or, in other words, that knowledge shows us what things really are, there is a conviction, strengthened by constant experience, that we never know things fully.  Every investigation into the nature of an object soon brings us to an enigma, a something more we do not know.  Failing to know this something more, we generally consider that we have fallen short of reaching the reality of the object.  We recognize, as it has been expressed, that we have been brought to a stand, and we therefore conclude that we are also brought to the end.  We arrive at what we do not know, and we pronounce that unknown to be unknowable; that is, we regard it as something different in nature from what we do know.  So far as I can see, the attitude of ordinary thought in regard to this matter might be fairly represented by saying, that it always begins by considering objects as capable of being known in their reality, or as they are, and that experience always proves the attempt to know them as they are to be a failure.  The effort is continued although failure is the result, and even although that failure be exaggerated and universalized into that despair of knowledge which we have described.  We are thus confronted with what seems to be a contradiction; a trust and distrust in knowledge.  It can only be solved by doing full justice to both of the conflicting elements; and then, if possible, by showing that they are elements, and not the complete, concrete fact, except when held together.

From one point of view, it is undeniable that in every object of perception, we come upon problems that we cannot solve.  Science at its best, and even when dealing with the simplest of things, is forced to stop short of its final secret.  Even when it has discovered its law, there is still apparently something over and above which science cannot grasp, and which seems to give to the object its reality.  All the natural sciences concentrated on a bit of iron ore fail to exhaust the truth in it:  there is always a “beyond” in it, something still more fundamental which is not yet understood.  And that something beyond, that inner essence, that point in which the laws meet and which the sciences fail to lift into knowledge, is regarded as just the reality of the thing.  Thus the reality is supposed, at the close of every investigation, to lie outside of knowledge; and conversely, all that we do know, seeing that it lacks this last element, seems to be only apparent knowledge, or knowledge of phenomena.