deductively from the principles of the instability of the homogeneous and the multiplication of effects. How far Mr. Spencer was here in advance of all other workers in this field will appear, when we consider that the doctrine of Evolution, as it now stands, was thus, in its universality, and in its chief outlines, announced by him two years before the appearance of Mr. Darwin's "Origin of Species."
A principle of natural changes more universal than any other known, applicable to all orders of phenomena, and so deep as to involve the very origin of things, having thus been established, the final step remained to be taken, which was, to give it the same ruling place in the world of thought and of knowledge that it has in the world of fact and of Nature. A principle running through all spheres of phenomena must have the highest value for determining scientific relations; and a genetic law of natural things must necessarily form the deepest root of the philosophy of natural things. It was in 1858, as Mr. Spencer informs me, while writing the article on the "Nebular Hypothesis," that the doctrine of Evolution presented itself as the basis of a general system under which all orders of concrete phenomena should be generalized. Already the conception had been traced out in its applications to astronomy, geology, biology, psychology, as well as all the various super-organic products of social activity; and it began to appear both possible and necessary that all these various concrete sciences should be dealt with in detail from the Evolution point of view. By such treatment, and by that only, did it appear practicable to bring them into relation so as to form a coherent body of scientific truth—a System of Philosophy.
It is proper in this place to state that, in contemplating the execution of so comprehensive a work, the first difficulty that arose was a pecuniary one. Mr. Spencer had frittered away the greater part of what little he possessed in writing and publishing books that did not pay their expenses, and a period of eighteen months of ill-health and enforced idleness consequent on the writing of one of them had further diminished his resources. His state of health was still such that he could work, at the outside, but three hours a day, and very frequently not even that, so that what little he could do in the shape of writing for periodicals, even though tolerably paid for it, did not suffice to meet the expenses of a very economical bachelor-life. How, then, could he reasonably hope to prosecute a scheme elaborating the doctrine of Evolution throughout all its departments in the way contemplated—a scheme that would involve an enormous amount of thought, labor, and inquiry, and which seemed very unlikely to bring any pecuniary return, even if it paid its expenses? Unable to see any solution of the difficulty, Mr. Spencer wrote, in July, 1858, to Mr. John Stuart Mill, explaining his project, and asking whether he thought that in the administration for India, in which Mr. Mill held office, there was likely to be any post, rather of trust than of much