There is no hope whatsoever for ethics, or religion, or philosophy—­no hope even for science—­in a theory which would apply evolution all the way up from inorganic matter to life, but which would postulate an absolute break at consciousness.  The connection between thought and things is there to begin with, whether we can account for it or not; if it were not, then natural science would be impossible.  It would be palpably irrational even to try to find out the nature of things by thinking.  The only science would be psychology, and even that would be the science of “symbols of an unknown entity.”  What symbols of an unknown can signify, or how an unknown can produce symbols of itself across an impassable gulf—­Mr. Spencer, Mr. Huxley, and Mr. Tyndall have yet to inform us.

It is the more necessary to insist on this, because the division between thought and matter, which is admitted by these writers, is often grasped at by their opponents, as a means of warding off the results which they draw from the theory of evolution.  When science breaks its sword, religion assails it, with the fragment.  It is not at once evident that if this chasm were shown to exist, knowledge would be a chimera; for there would be no outer world at all, not even a phenomenal one, to supply an object for it.  We must postulate the ultimate unity of all beings with each other and with the mind that knows them, just because we are intellectual and moral beings; and to destroy this unity is to “kill reason itself, as it were, in the eye,” as Milton said.

Now, evolution not only postulates unity, or the unbroken continuity of all existence, but it also negates all differences, except those which are expressions of that unity.  It is not the mere assertion of a substratum under qualities; but it implies that the substratum penetrates into the qualities, and manifests itself in them.  That which develops—­be it plant, child, or biological kingdom—­is, at every stage from lowest to highest, a concrete unity of all its differences; and in the whole history of its process its actual content is always the same.  The environment of the plant evokes that content, but it adds nothing to it.  No addition of anything absolutely new, no external aggregation, no insertion of anything alien into a growing thing, is possible.  What it is now, it was in the beginning; and what it will be, it is now.  Granting the hypothesis of evolution, there can be no quarrel with the view that the crude beginnings of things, matter in its most nebulous state, contains potentially all the rich variety of both natural and spiritual life.

But this continuity of all existence may be interpreted in two very different ways.  It may lead us either to radically change our notions of mind and its activities, or “to radically change our notions of matter.”  We may take as the principle of explanation, either the beginning, or the end of the process of development.  We may say of the simple and crass, “There is all that your rich universe really means”; or we may say of the spiritual activities of man, “This is what your crude beginning really was.”  We may explain the complex by the simple, or the simple by the complex.  We may analyze the highest back into the lowest, or we may follow the lowest, by a process of synthesis, up to the highest.