Probably the contribution of evolutionary theory to our knowledge of mind that bulks larger than any other is the discovery, growing clearer with each year of study, that the human mind also is fundamentally just a group of activities, greatly complicated, mysteriously unified, wonderfully resourceful, marvelously progressive, self-conscious, moreover, and free, and yet at bottom a system of activities, no more. Activity, doing, will, that is the core of us, the rest, sensation, feeling, idea, they are but the effects of our own or of other activities. A spirit, in etymology, is just the active principle of a liquid: and activity is what distinguishes the quick from the dead. Even superman, in his ascending excellence, we must believe to be but vaster and more skillfully and perfectly ordered activity. And man is distinguished from his humbler brethren, and higher animals from lower, by what they can do. Man hesitates, chooses, plans, contrives and fits things together in fulfilment of his purposes. As we descend the animal scale these activities first diminish, and then disappear, dull routine taking their place. But this implies, not a substitute for activity, merely its simplification. And the same decrease of complexity obtains as the transition is made from animals to plants, and from plants to inorganic matter. This no doubt seems a hard saying to those who have not followed discoveries and discussions in this field; but to those who have it is little more than a commonplace. We do not yet know how inorganic activities become systematized into organic, or what determines their form as vegetable or animal. The cell still keeps its secret. But that inorganic is transformed into organic is plainly shown by every breath taken, every meal eaten, and every development of an embryo to maturity, as the reverse transition is shown by all waste processes, including death itself. As men organize themselves into states, and lesser associations, which have organs and modes of activity which no man has, so, it would seem, molecules organize themselves into cells, and cells into living beings, which differ even more in structure and function from the units composing them.
In substance, then, comparative psychology teaches that a man is a complicated system of activities, sensitive and conscious; an animal a less complicated system, sensitive and conscious; a plant a still less complicated system, sensitive, but only dimly conscious, if at all so; and organic matter, the simplest system of activities we know, whether either sensitive or conscious we are not yet prepared to say. So much is quite plain. But all is not said. It is also plain that inorganic, or so-called dead matter, has, in the way of evolution, developed into organic or living matter, and that matter is being daily transformed into living, yes, into conscious, beings, and living and even conscious beings are being daily transformed back into mere matter. These plain facts of themselves throw not a little light on the nature of matter. For they show that the constitution and the nature of matter
