Turning now from the objective aspect to the subjective aspect we pass from neural processes to states of consciousness. In the language of the identity hypothesis, here provisionally adopted, the states of consciousness in the dog’s mind, are the subjective aspect of what, from the objective aspect, are the molecular vibrations of his brain-tissues. And as in considering the matter objectively, so now in regarding the mental aspect, we must ask from what the complex and orderly states of consciousness of the dog’s mind have been evolved. In the fertilised ovum from which the dog is developed, (and the same is true of the amœboid ancestor from which, hypothetically, the race of dogs has been evolved,) nothing so complex as a state of consciousness is to be found. From what then have the states of consciousness been evolved? Do we not seem forced by parity of reasoning to answer: From something more simple than consciousness but of the same order of existence, which answers subjectively to the simpler organic energy of the fertilised ovum? Such, at any rate, is the hypothesis which appears to me the most philosophical and the most logically consistent. It requires, however, no little effort of thought to conceive the existence of those elementary states from which consciousness may have had its origin. We may be aided in doing so, perhaps, if we fix our attention on the close association of brain-energy and states of consciousness, regarding them as _distinguishable_ but not _separable_. Now the nervous energy of the brain is extraordinarily complex; and yet we believe that it arises by a process of continuous development from the much less complex energy of the fertilised ovum. In the ovum there is no brain-energy; there is only the far simpler germinal energy from which it is evolved. So too, the consciousness in the dog’s mind is wonderfully complex; but if it has arisen by a process of development, it must have been evolved from something of like nature only indefinitely simpler. May we not fairly suppose, therefore, that in the fertilised ovum, though there is no consciousness, there are the germinal states from which consciousness may be evolved? Or to put the matter tersely, may we not say: As the complex molecular vibrations of the brain are to the simpler molecular vibrations of the ovum; so are the complex states of consciousness associated with the former to the simpler states of infra-consciousness, if we may so call them, associated with the latter? It is the association of consciousness and infra-consciousness with energy—its objective manifestation—that is the distinguishing feature of the view which I am endeavoring to set forth. Concomitant with the evolution of higher modes of organic energy from those lowly modes which alone obtain in the ovum or the amœba, is the evolution of consciousness from lowly modes of infra-consciousness.