Henry George The Science of Political Economy Book I, The Meaning of Political Economy Chapter I, The Three Factors of the World Showing the Constituents of All We Perceive

The word factor, in commercial use, means one who acts as agent for another. In mathematical use, it means one of the quantities which multiplied together form a product. Hence in philosophy, which may be defined as the search for the nature and relations of things, the word factor affords a fit term for the elements which bring about a result, or the categories into which analysis enables us to classify these elements.

In the world - I use the term in its philosophic sense of the aggregate or system of things of which we are cognizant and of which we ourselves are part - we are enabled by analysis to distinguish three elements or factors:

1. That which feels, perceives, thinks, wills; which to distinguish, we call mind or soul or spirit.

2. That which has a mass or weight, and extension or form; which to distinguish, we call matter.

3. That which acting on matter produces movement; which to distinguish, we call motion or force or energy.

We cannot, in truth, directly recognize energy apart from matter; nor matter without some manifestation of energy; nor mind or spirit unconjoined with matter and motion. For though our own consciousness may testify to our own essentially spiritual nature, or even at times to what we take to be direct evidence of pure spiritual existence, yet consciousness itself begins with us only after bodily life has already begun, and memory by which alone we can recall past consciousness is later still in appearing. It may be that what we call matter is but a form of energy; and it may perhaps be that what we call energy is but a manifestation of what we call mind or soul or spirit; and some have even held that from matter and its inherent powers all else originates. Yet though they may not be in fact separable by us, and though it may be that at bottom they are one, we are compelled in thought to distinguish these three as independent, separable elements, which in their actions and reactions make up the world as it is presented to our perception.

Of these from our standpoint, that which feels, perceives, thinks, wills, comes first in order of priority, for it is this which is first in our own consciousness, and it is only through this that we have consciousness of any other existence. In this, as our own consciousness testifies, is the initiative of all our own motions and movements, so far as consciousness and memory shed light; and in all cases in which we can trace the genesis of anything to its beginning we find that beginning in thought and will. So clear, so indisputable is the priority of this spiritual element that wherever and whenever men have sought to account for the origin of the world they have always been driven to assume a great spirit or God. For though there be atheistic theories, they always avoid the question of origin, and assume the world always to have been.