There are many things eminently characteristic of M. Comte’s second career, in this revision of the results of his first.  Under the head of Biology, and for the better combination of that science with Sociology and Ethics, he found that he required a new system of Phrenology, being justly dissatisfied with that of Gall and his successors.  Accordingly he set about constructing one e priori, grounded on the best enumeration and classification he could make of the elementary faculties of our intellectual, moral, and animal nature; to each of which he assigned an hypothetical place in the skull, the most conformable that he could to the few positive facts on the subject which he considered as established, and to the general presumption that functions which react strongly on one another must have their organs adjacent:  leaving the localities avowedly to be hereafter verified, by anatomical and inductive investigation.  There is considerable merit in this attempt, though it is liable to obvious criticisms, of the same nature as his own upon Gall.  But the characteristic thing is, that while presenting all this as hypothesis waiting for verification, he could not have taken its truth more completely for granted if the verification had been made.  In all that he afterwards wrote, every detail of his theory of the brain is as unhesitatingly asserted, and as confidently built upon, as any other doctrine of science.  This is his first great attempt in the “Subjective Method,” which, originally meaning only the subordination of the pursuit of truth to human uses, had already come to mean drawing truth itself from the fountain of his own mind.  He had become, on the one hand, almost indifferent to proof, provided he attained theoretic coherency, and on the other, serenely confident that even the guesses which originated with himself could not but come out true.

There is one point in his later view of the sciences, which appears to us a decided improvement on his earlier.  He adds to the six fundamental sciences of his original scale, a seventh under the name of Morals, forming the highest step of the ladder, immediately after Sociology:  remarking that it might, with still greater propriety, be termed Anthropology, being the science of individual human nature, a study, when rightly understood, more special and complicated than even that of Society.  For it is obliged to take into consideration the diversities of constitution and temperament (la reaction cerebrale des visceres vegetatifs) the effects of which, still very imperfectly understood, are highly important in the individual, but in the theory of society may be neglected, because, differing in different persons, they neutralize one another on the large scale.  This is a remark worthy of M. Comte in his best days; and the science thus conceived is, as he says, the true scientific foundation of the art of Morals (and indeed of the art of human life), which, therefore, may, both philosophically and didactically, be properly combined with it.