Excerpt:

THE most difficult thing is to know what we do know, and what we do not know.

Therefore, desiring to know anything, we shall before all else determine WHAT we accept as given, and WHAT as demanding definition and proof; that is, determine WHAT we know already, and WHAT we wish to know.

In relation to the knowledge of the world and of ourselves, the conditions would be ideal could we venture to accept nothing as given, and count all as demanding definition and proof. In other words, it would be best to assume that we know nothing, and make this our point of departure.

But unfortunately such conditions are impossible to create. Knowledge must start from some foundation, something must be recognized as known; otherwise we shall be obliged always to de-fine one unknown by means of another.

Looking at the matter from another point of view, we shall hesitate to accept as the known things—as the given ones—those in the main completely unknown, only presupposed, and therefore the things sought for. Should we do this, we are likely to fall into such a dilemma as that in which positive philosophy now finds itself—and by positive philosophy I mean a general trend of thought based on the data of those sciences which are now accepted as experimental and positive. This philosophy is founded on the existence of matter (materialism) or energy: that is, of a force, or motion, (energeticism); though in reality matter and motion were always the unknown x and y, and were defined by means of one another.

It must be perfectly clear to everyone that it is impossible to accept the thing sought as the given; and impossible to define one unknown by means of another. The result is nothing but the identity of the unknown: x=y, y=x.

This identity of the unknown is the ultimate conclusion to which positive philosophy comes.

Matter is that in which proceed the changes called motion: and motions are those changes which proceed in matter.

_______ But what do we know?

We know that with the very first awakening of knowledge, man is confronted with two obvious facts:

The existence of the world in which he lives; and the existence of psychic life in himself.

Neither of these can he prove or disprove, but they are facts: they constitute reality for him.

It is possible to meditate upon the mutual correlation of these two facts. It is possible to try to reduce them to one; that is, to regard the psychic or inner world as a part, reflection, or function of the world, or the world as a part, reflection, or function of that inner world. But such a procedure constitutes a departure from facts, and all such considerations of the world and of the self, to the ordinary non-philosophical mind, will not have the character of obviousness. On the contrary the sole obvious fact remains the antithesis of I and Not-I—our inner psychic life and the outer world.,

Further on we shall return to this fundamental thesis. But thus far we have no basis on which to found a contradiction of the obvious fact of the existence of ourselves—i.e., of our inner life—and of the world in which we live. This we shall therefore accept as the given.

This however is the only thing that we have the right to accept as given: all the rest demands proof and definition in terms of these two given data.

Space, with its extension; time, with the idea of before, now, after; quantity, mass, substantiality; number, equality and inequality; identity and difference; cause and effect; the ether, atoms, electrons, energy, life, death—all things that form the foundation of our so-called knowledge: these are the unknown things.

The existence in us of psychic life, i.e., of sensations, perceptions, conceptions, reasoning, feeling, desires etc., and the existence of the world outside of us—from these two fundamental data immediately proceed our common and clearly understood division of everything that we know into subjective and objective.

Everything that we accept as a property of the world, we call objective; and everything that we accept as a property of our psyche, we call subjective.

The subjective world we recognize directly: it is in ourselves—we are one with it.

The objective world we picture to ourselves as existing somewhere outside of us—we and it are different things.

It seems to us that if we should close our eyes, then the objective world would continue to exist, such as we just saw it; and if our inner life were to disappear, so would the subjective world disappear—yet the objective world would exist as before, as it existed at the time when we were not; when our subjective world was not.