Professor Tyndall has told us that the only scientific method is to prolong the method of nature from the present into the past, taking her observed uniformity for our only guide, and in like manner we have heard it laid down by Professor Romanes, that we must assume as a first principle[{49}] that the laws of nature are always and everywhere the same, and that by their uniform operation everything is done. It is therefore quite clear that as no man was present when life first made its appearance, to observe and record whence it came, the only way in which we can possibly proceed, without violating every scientific canon, is to argue from what happens now, to what must have happened then,—to show that inorganic matter can in fact generate organic life, and to conclude that the same laws must have worked the same results in the past as they do in the present.
But this is precisely what cannot be done, for one of the most conclusive results of modern research has been to show that in the present world spontaneous generation never occurs, that living things come only from living parents, and that from organic matter alone can the smallest particle of organic matter be derived. Omne vivum e vivo, omnis cellula e cellula, omnis nucleus e nucleo. Upon this point there is now complete agreement amongst scientific authorities, and what is most remarkable, none are more strenuous in upholding the doctrine of Biogenesis,[74] than some of those who with equal vehemence proclaim the doctrine of Evolution for which the occurrence of spontaneous generation is a necessity.
Never, for example, were there Evolutionists[{50}] more pronounced than Professors Huxley and Tyndall, and they both saw clearly that without spontaneous generation there could not have been evolution such as they maintained. Yet when the occurrence of spontaneous generation, here and now, was asserted by Bastian and Burdon Sanderson, they, following in the wake of Pasteur, repudiated the notion, and Tyndall in particular conclusively disproved the experiments by which it was supported.[75] As Huxley wrote to Charles Kingsley:[76]
I am glad you appreciate the rich absurdities of spontogenesis. Against the doctrine of spontaneous generation in the abstract I have nothing to say. Indeed it is a necessary corollary from Darwin's views if legitimately carried out.
A few years later, writing to Dr. Dohrn[77] upon the same subject, he made use of a phrase—which in his mouth expressed the uttermost limit of disbelief: "Transubstantiation will be nothing to this if it turns out true."
In the same year as President of the British Association he chose for the subject of his inaugural address, "Biogenesis and Abiogenesis," and, after a careful examination of the case for each, pronounced the former "to be victorious all along the line."
In spite of all this, however, he assured himself[{51}] as an Evolutionist that spontaneous generation must once have been not only a possibility but a fact. In the same Presidential address, after piling up evidence against it—he thus continued:[78]
But though I cannot express this conviction of mine too strongly, I must carefully guard myself against the supposition that I intend to suggest that no such thing as Abiogenesis has ever taken place in the past, or ever will take place in the future. With organic chemistry, molecular physics and physiology yet in their infancy, and every day making prodigious strides, I think it would be the height of presumption for any man to say that the conditions under which matter assumes the properties we call "vital" may not, some day, be artificially brought together. All I feel justified in affirming is that I see no reason for affirming that the feat has been performed yet.
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[{52}] 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[{53}] 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.