Such symbolism will harmonize with the peculiar reproduction, before mentioned, of heads in the body of certain annelids, with the facts of serial homology, as well as those of bilateral and
vertical symmetry. Also, as the atoms of a resonant body may be made to give out sound by the juxtaposition of a vibrating tuning-fork, so it is conceivable that the physiological units of a living organism may be so influenced by surrounding conditions (organic and other) that the accumulation of these conditions may upset the previous rhythm of such units, producing modifications in them—a fresh chord in the harmony of nature—a new species!
But it may be again objected that to say that species arise by the help of an innate power possessed by organisms is no explanation, but is a reproduction of the absurdity, l'opium endormit parcequ'il a une vertu soporifique. It is contended, however, that this objection does not apply, even if it be conceded that there is that force in Molière's ridicule which is generally attributed to it.[[231]] Much, however, might be said in opposition to more than one of that brilliant dramatist's smart philosophical epigrams, just as to the theological ones of Voltaire, or to the biological one of that other Frenchman who for a time discredited a cranial skeletal theory by the phrase "Vertèbre pensante."[[232]]
In fact, however, it is a real explanation of how a man lives to say that he lives independently, on his own income, instead of being supported by his relatives and friends. In the same way, there is fully as real a distinction between the production of new specific manifestations entirely ab externo, and by the production of the same through an innate force and tendency,
the determination of which into action is occasioned by external circumstances.
To say that organisms possess this innate power, and that by it new species are from time to time produced, is by no means a mere assertion that they are produced, and in an unknown mode. It is the negation of that view which deems external forces alone sufficient, and at the same time the assertion of something positive, to be arrived at by the process of reductio ad absurdum.
All physical explanations result ultimately in such conceptions of innate power, or else in that of will force. The far-famed explanation of the celestial motions ends in the conception that every particle of matter has the innate power of attracting every other particle directly as the mass, and inversely as the square of the distance.
We are logically driven to this positive conception if we do not accept the view that there is no force but volition, and that all phenomena whatever are the immediate results of the action of intelligent and self-conscious will.
We have seen that the notion of sudden changes—saltatory actions in nature—has received countenance from Professor Huxley.[[233]] We must conceive that these jumps are orderly, and according to law, inasmuch as the whole cosmos is such. Such orderly evolution harmonizes with a teleology derived, not indeed from external nature directly, but from the mind of man. On this point, however, more will be said in the next chapter. But, once more, if new species are not manifested by the action of external conditions upon minute indefinite individual differences, in what precise way may we conceive that manifestation to have taken place?
Are new species now evolving, as they have been from time to time evolved? If so, in what way and by what conceivable means?