The important truth that it has been sought to reach by these considerations is, that organic evolution is but one of the minor manifestations of universal evolution. It occurs at a stage of the process when the struggle between the contending forces is very great, if not at its greatest. It is the immediate product of that struggle, and cannot exist when either the one or the other greatly predominates. The force to which we universally ascribe all possibility of life is the force which is tending to disintegrate the matter of the globe by absorbing the motion of the sun. The force which constitutes evolution proper is that which bears down all life and reduces the face of Nature to a desert waste. The interaction of these two forces, where they are suitably proportioned, effects the organization of portions of the matter on the globe, and organization itself is life. The period of greatest organic perfection on a planet is therefore very different from the period of its greatest cosmical perfection, which corresponds with that of complete equilibration. Cosmical evolution is the history of the universe, organic evolution is a transient episode in the life of a paltry planet. We can only console ourselves with the belief that, but for this trifling digression of Nature, no being would have existed capable of formulating the laws of the universe.
Organic evolution must not, however, be restricted to the mere span which the life of an individual represents. To fully comprehend its scope, the conception of the organic aggregate should be extended to embrace all the life, past, present, and future, on the globe. The mysterious process of reproduction, unknown to all other aggregates, has the effect of binding all living organisms into one continuous whole, and giving to all terrestrial life the stamp of unity. The individuals of a race or species do not represent so many distinct aggregates. The qualities of antecedent forms, whether inherited or acquired, are transmitted to subsequent forms, thus conserving, as it were, all the organization previously evolved. Although the dissolution of the individual aggregate takes place, the work of evolution which has been going on within it is passed on to a new generation, to be there continued and again transmitted. The individual, therefore, becomes of comparatively small importance. The real organic aggregate is the race. The race alone is capable of receiving and preserving all the products of organic evolution. Ontogenetic development is lost sight of in the march of phylogenetic development. The individual is merged in the species, the species in the genus, the order, the class, and all are finally swallowed up in the tout ensemble of organized existence. Organic being, as such, is the final term to which the generalization must be carried before the true scope of organic evolution can be adequately grasped by the mind. Individuals perish and are decomposed; species become extinct; genera, families, and whole classes, are swept from the earth. The broadest divisions into which the organic kingdoms of Nature have been classified have each their