(_a_) _Simple sensation and consciousness._ As regards the actual origin of the higher form of life which distinguishes the animal from the vegetable, we are obviously no better informed than we have found ourselves to be concerning the first beginnings of life in any form,--no evidence as to the actual facts being available, or even possible, for our enlightenment. Once more we can only argue from the present to the past, and enquire whether the progress of science has made it more reasonable to suppose than it seemed in pre-scientific days that animal life has been spontaneously evolved, either from inanimate matter or from the vegetative life of plants. This enquiry so much resembles that which we have just concluded as to make it unnecessary to pursue it at any length. We find, in fact, that men of Science who have no prepossessions whatever against Evolution, and would willingly accept the Law of Continuity at all points, if only evidence were forthcoming, find here not only an unsolved problem, but one even more difficult than the Origin of Life itself. Du Bois-Reymond for example places this amongst his "transcendental" enigmas, to which an answer will never be found, whereas he thinks that the origin of vegetable life, although at present a mystery, may one day be explained. The expression of his opinion,--that by no possibility can we ever understand how consciousness could be evolved from matter--has, he tells us[107] been vehemently contradicted, but, he adds, nothing in the way of argument, or beyond mere assumptions, has been brought against him. Of these assumptions he notices only that of Professor Haeckel, "the Prophet of Jena," who protests against such limitations of our possibilities as treason to the sacred cause of Evolution. The progress we have made in intellect, says Haeckel, beyond our barbarous progenitors, is sufficient to show that we are on the high road of development towards a stage as far in advance of the present, as this is of the past; and when that is attained, our knowledge will be full and will embrace all this. But, asks Du Bois-Reymond in reply, is this mighty progress of ours so very evident within the period concerning which we have any information? Has the mental capacity of our race notably improved since Homer?[108] or its faculty of thinking since Plato and Aristotle? At our present rate of progress, long before the high-water mark prophesied by Haeckel is reached, the earth will have become uninhabitable. And, were it otherwise, the highest point of intellect to which conceivably man could attain, would be that of the "sufficient intelligence" whereof we have been told, which, from an inspection of the cosmic nebula could foretell all that was to issue from it. And, adds Du Bois-Reymond, even could we do this, we should still be unable to understand the origin of consciousness, which would require intelligence of another order than ours, however magnified.