The material, the carnal, the earthy, has been so long under the ban, so long associated in our minds with that which hinders and degrades, and with the source and province of evil, that it will take science a long time to redeem it and lift it again to its proper place.
It jars upon our sensibilities and disturbs our preconceived notions to be told that the spiritual has its root in the carnal and is as truly its product as the flower is the product of the roots and the stalk of the plant. The conception does not cheapen or degrade the spiritual, it elevates the carnal, the material. To regard the soul and body as one, or to ascribe to consciousness a physiological origin, is not detracting from its divinity, it is rather conferring divinity upon the body. One thing is inevitably linked with another, the higher forms with the lower forms, the butterfly with the grub, the flower with the root, the food we eat with the thought we think, the poem we write, or the picture we paint, with the processes of digestion and nutrition. How science has enlarged and ennobled and purified our conception of the universe; how it has cleaned out the evil spirits that have so long terrified mankind, and justified the verdict of the Creator: "and behold it was good." With its indestructibility of matter, its conservation of energy, its violability of cause and effect, its unity of force and elements throughout sidereal space, it has prepared the way for a conception of man, his origin, his development, and in a measure his destiny, that at last makes him at home in the universe.
How much more consistent it is with what we know of the unity of nature to believe that one species should have come through another, that man should have come through the brute rather than have been grafted upon him from without. Unfolding and ever unfolding, upward, and onward, from the lower to the higher, from the simple to the complex—that has been the course of organic evolution from the first.
One thinks of the creative energy as working along many lines, only one of which eventuated in man; all the others fell short or terminated in lower forms. Hence, while we think of man as capable of, and destined to, still higher development, we look upon the lower orders as having reached the end of their course, and conclude there is no to-morrow for them.
The anthropoid apes seem indeed like preliminary studies of man, or rejected models of the great inventor who was blindly groping his way to the higher form. The ape is probably our ancestor in no other sense than this. Nature seems to have had man in mind when she made him, but evidently she lost interest in him, humanly speaking, and tried some other combination. The ape must always remain an ape. Some collateral branch doubtless gave birth to a higher form, and this to a still higher, till we reach our preglacial forbears. Then some one branch or branches distanced all others, leaving rude tribes by the way in whom development seemed arrested, till we reach the dawn of history.
The creative energy seems ever to have been pushing out and on, and yet ever leaving a residue of forms behind. The reptiles did not all become birds, nor the invertebrates all become vertebrates, nor the apes all become men, nor the men all become Europeans. Every higher form has a base or background of kindred lower forms out of which it seems to have emerged, and to which it now and then shows a tendency to revert. And this is the order of nature everywhere, in our own physiology and psychology, not less than in the evolution of the forms of life. Do not our highest ideals have their rise and foundation in sensation and experience? There is no higher without first the lower, and the lower does not all become the higher.
The blood relationship between man and the anthropoid apes, as shown in the fact that human blood acts poisonously upon and decomposes the blood of the lower apes and other mammals, but is harmless to the blood of the anthropoid apes, and affiliates with it, is very significant. It convinces like a demonstration. Transfer the blood of the dog to the fox or the wolf, or vice versa, and all goes well; they are brothers. Transfer the blood of the dog to the rabbit, or vice versa, and a struggle for life immediately takes place. The serum of one blood destroys the cells of the other. This fact confirms Huxley's statement that the anatomical difference between man and the anthropoid apes is less than the corresponding difference between the latter and the lower apes.