The great result of speculation since the time of Kant is to teach us to recognize that objects are essentially related to mind, and that the principles which rule our thought enter, so to speak, into the constitution of the things we know. A very slight acquaintance with the history even of psychology, especially in modern times, shows that facts are more and more retracted into thought. This science, which began with a sufficiently common-sense view, not only of the reality and solidity of the things of the outer world, but of their opposition to, or independence of thought, is now thinning that world down into a mere shadow—a something which excites sensation. It shows that external things as we know them, and we are not concerned in any others, are, to a very great extent, the product of our thinking activities. No one will now subscribe to the Lockian or Humean view, of images impressed by objects on mind: the object which "impresses" has first to be made by mind, out of the results of nervous excitation. In a word, modern psychology as well as modern metaphysics, is demonstrating more and more fully the dependence of the world, as it is known, on the nature and activity of man's mind. Every explanation of the world is found to be, in this sense, idealistic; and in this respect, there is no difference whatsoever between the interpretation given by science and that of poetry, or religion, or philosophy. If we say that a thing is a "substance," or has "a cause"; if, with the physicist, we assert the principle of the transmutation of energy, or make use of the idea of evolution with the biologist or geologist; nay, if we speak of time and space with the mathematician, we use principles of unity derived from self-consciousness, and interpret nature in terms of ourselves, just as truly as the poet or philosopher, who makes love, or reason, the constitutive element in things. If the practical man of the world charges the poet and philosopher with living amidst phantoms, he can be answered with a "Tu quoque." "How easy," said Emerson, "it is to show the materialist that he also is a phantom walking and working amid phantoms, and that he need only ask a question or two beyond his daily questions to find his solid universe proving dim and impalpable before his sense." "Sense," which seems to show directly that the world is a solid reality, not dependent in any way on thought, is found not to be reliable. All science is nothing but an appeal to thought from ordinary sensuous opinion. It is an attempt to find the reality of things by thinking about them; and this reality, when it is found, turns out to be a law. But laws are ideas; though, if they are true ideas, they represent not merely thoughts in the mind, but also real principles, which manifest themselves in the objects of the outer world, as well as in the thinker's mind.
It is not possible in such a work as this, to give a carefully reasoned proof of this view of the relation of thought and things, or to repeat the argument of Kant. I must be content with merely referring to it, as showing that the principles in virtue of which we think, are the principles in virtue of which objects as we know them exist; and we cannot be concerned with any other objects. The laws which scientific investigation discovers are not only ideas that can be written in books, but also principles which explain the nature of things. In other words, the hypotheses of the natural sciences, or their categories, are points of view in the light of which the external world can be regarded as governed by uniform laws. And these constructive principles, which lift the otherwise disconnected world into an intelligible system, are revelations of the nature of intelligence, and only on that account principles for explaining the world.
"To know,
Rather consists in opening out a way
Whence the imprisoned splendour may escape,
Than in effecting entry for a light
Supposed to be without."A
A: Paracelsus.
In this sense, it may be said that all knowledge is anthropomorphic; and in this respect there is no difference between the physics, which speaks of energy as the essence of things, and the poetry, which speaks of love as the ultimate principle of reality. Between such scientific and idealistic explanations there is not even the difference that the one begins without and the other within, or that the one is objective and the other subjective. The true distinction is that the principles upon which the latter proceed are less abstract than those of science. "Reason" and "love" are higher principles for the explanation of the nature of things than "substance" or "cause"; but both are forms of the unity of thought. And if the latter seem to have nothing to do with the self, it is only because they are inadequate to express its full character. On the other hand, the higher categories, or ideas of reason, seem to be merely anthropomorphic, and, therefore, ill-suited to explain nature, because the relation of nature to intelligence is habitually neglected by ordinary thought, which has not pressed its problems far enough to know that such higher categories can alone satisfy the demand for truth.