The question concerning the origin and nature of Life is of supreme and vital importance not only for those who speak of Evolution as a force or principle by which everything is guided and governed, but also for such as understand by the term no more than a process which they say has actually occurred. Evolutionists of this second class disclaim, with Huxley, any "philosophy of Evolution." They are content to take the world as a going concern, at the farthest point in the past to which, even speculatively, Science can trace it, as that vast primordial nebula of which we have heard.[63] Given this,--assuming the existence of such a nebula, constituted as they suppose,--they believe that the whole subsequent history of the world is fully explained by the uniform action of the same laws of matter which we find in operation to-day. Not only is the establishment of our Solar System, of sun and planets, to be thus accounted for, but likewise the production of life, of the organic world of plants and animals. Hence it necessarily follows that life must originally have been evolved naturally from lifeless matter, for all are agreed that not only in the nebula, but on the earth when it first started its independent career, life did not, and could not, exist. There has been [says Virchow][64] a beginning of life, since geology points to epochs in the formation of the earth when life was impossible, and when no vestige of it is to be found. If the evolution hypothesis is true, [says Huxley][65] living matter must have arisen from not-living matter; for by the hypothesis the condition of the globe was at one time such that living matter could not have existed in it, life being entirely incompatible with the gaseous state. There was a time [says Tyndall][66] when the earth was a red-hot molten globe, on which no life could exist. Accordingly, as Professor Huxley acknowledges, spontaneous generation is an evolutionary necessity. Unless such generation can be shown to have taken place, or at the very least unless it can be shown to be naturally possible, the theory which requires it cannot be an established truth. But it is precisely as a scientifically established truth that the doctrine of Evolution is presented to us, so firmly established indeed that we are warned "to doubt it is to doubt science."[67] It presents itself, moreover, as the most precious result of modern research, the appearance of which is as a sunrise illuminating the field of knowledge.[68] This being so, and it being the first principle of Science that we should take nothing on faith and accept only what can be proved, it is our plain duty to satisfy ourselves, as scientific methods alone can rightly satisfy us, that a doctrine of such paramount importance is entitled to demand our acceptance. What methods can claim to be scientific, all are agreed. Advances in science, Professor Tait warns us,[69]