Open main menu

Page:Popular Science Monthly Volume 18.djvu/111

This page has been validated.

ject is in life—how it is enjoying itself, what food it is seeking, or from what enemy it is flying.

And, fortunately for us, there are an order and arrangement in this immense multitude, and in the same way as we can read and understand the history of different nations which form the great human family spread over the earth, and enter into their feelings and their struggles, though we can not know all the people themselves; so, with a little trouble, we may learn to picture to ourselves the general life and habits of the different branches of the still greater family of life, so as to be ready, by and by, to make personal acquaintance with any particular creature if he comes in our way.



AN objection made to the formula of evolution by a sympathetic critic, Mr. T. E. Cliffe Leslie, calls for notice. It is urged in a spirit widely different from that displayed by Mr. Kirkman and his applauder. Professor Tait; and it has an apparent justification. Indeed, many readers, who before accepted the formula of evolution in full, will, after reading Mr. Cliffe Leslie's comments, agree with him in thinking that it is to be taken with the qualifications he points out. We shall find, however, that a clearer apprehension of the meanings of the words used and a clearer apprehension of the formula in its totality exclude the criticisms Mr. Leslie makes.

In the first place he dissociates from one another those traits of evolution which I have associated, and which I have alleged to be true only when associated. He quotes me as saying that a change from the homogeneous to the heterogeneous characterizes all evolution; and he puts this at the outset of his criticism as though I made this change the primary characteristic. But if he will refer to "First Principles," Part II, Chapter XIV (in the second and subsequent editions), he will find it shown that under its primary aspect evolution "is a change from a less coherent form to a more coherent form, consequent on the dissipation of motion and integration of matter." The next chapter contains proofs that the change from homogeneity to heterogeneity is a secondary change, which, when conditions allow, accompanies the change from the incoherent to the coherent. At the beginning of the chapter after that come the sentences—"But now, does this generalization express the whole truth? Does it include everything essentially characterizing evolution and exclude everything else? . . . A