And looking back through the prodigious vista of the past, I find no record of the commencement of life, and therefore I am devoid of any means of forming a definite conclusion as to the conditions of its appearance. Belief, in the scientific sense of the word, is a serious matter, and needs strong foundations. To say, therefore, in the admitted absence of evidence, that I have any belief as to the mode in which the existing forms of life have originated, would be using words in a wrong sense. But expectation is permissible where belief is not; and if it were given me to look beyond the abyss of geologically recorded time to the still more remote period when the earth was passing through physical and dynamical conditions, which it can no more see again than a man can recall his infancy, I should expect to be a witness of the evolution of living protoplasm from not living matter.... That is the expectation to which analogical reasoning leads me; but I beg you once more to recollect that I have no right to call my opinion anything but an act of philosophical faith. Here we have the whole state of the case put for us in a nutshell. On the one hand, all known facts are against the idea of spontaneous generation, and therefore, so far as she can at present go, the verdict of Science must condemn that supposition. But, on the other hand, the fundamental principle of Evolution cannot be justified unless spontaneous generation has taken place, and accordingly, although Evolution is the very thing which we should be engaged in establishing by the evidence of facts, it is held to be reasonable and scientific to infer that facts which we cannot verify must exist because they are wanted. It is admitted that the requisite evidence is lacking, and therefore we must not go so far as to express belief in the facts: but we may indulge in expectations,--which seem, however, to imply belief in the thing expected,--and meanwhile we may go on believing firmly in the Evolution theory itself, which includes belief in the missing facts. This, we are told, is "philosophical faith." But, to say nothing of what we have heard from others, Professor Huxley elsewhere[79] warns us against faith as the one unpardonable sin: and as we have heard him declare the man of science has learned to believe in justification, not by faith, but by verification. And as to the expectation which he avowed, there appears to be no slight force in the response of his adversary Dr. Bastian:[80]