We must also be permitted to bear in mind that evolution, though it may explain everything else, cannot explain itself. What is the origin of the movement, and by what power the order of development is prescribed, are questions yet unsolved by physical science. That the solution, if it could be supplied, would involve anything arbitrary, miraculous, or at variance with the observed order of things, need not be assumed; but it might open a new view of the universe, and dissipate for ever the merely mechanical accounts of it. In the meantime we may fairly enter a caveat against the tacit insinuation of an unproved solution. Science can apparently give no reason for assuming that the first cause, and that which gives the law to development, is a blind force rather than an archetypal idea. The only origination within our experience is that of human action, where the cause is an idea. Science herself, in fact, constantly assumes an analogous cause for the movements of the universe in her use of the word "law," which necessarily conveys the notion, not merely of observed co-existence and sequence, but of the intelligent and consistent action of a higher power, on which we rely in reasoning from the past to the future, as we do upon consistency in the settled conduct of a man. Unspeakably momentous, however, we once more admit, the discovery is, and great is the debt of gratitude due to its illustrious authors. Yet it seems not unreasonable to ask whether in some respects we are not too much under its immediate influence, and whether the revolution of thought, though destined ultimately to be vast, may not at present have somewhat overpassed its bounds. Is it not possible that the physical origin of man may be just now occupying too large a space in our minds compared with his ulterior development and his final destiny? With our eyes fixed on the "Descent," newly disclosed to us, may we not be losing sight of the _Ascent_ of man?