Spencer's principle is that there is an “Antagonism,” or, as we may rather say, an inverse ratio, between “Individuation” and “Genesis”--between the proportion of energy expended upon the individual and the proportion expended upon the continuance of the race. Thus “Individuation,” meaning all those processes which maintain and expand the life of the individual, and “Genesis,” meaning all those processes which involve the formation of new individuals--are necessarily antagonistic. Every higher degree of individual evolution is followed by a lower degree of race multiplication, and _vice versâ_. Increase in bulk (_cf._ the elephant), complexity or activity involves diminution in fertility, and _vice versâ_. This is an obvious _à priori_ principle. Should the reader declare that there must be something the matter with an asserted principle of progress which leads in theory or in practice to the production of a childless generation, and therefore the end of all progress, and that this principle suggests that the most completely developed man and woman cannot be parents--then I would join in the chorus of fathers and mothers generally, who would say that, in human parenthood, if not, indeed, in sub-human parenthood, the antagonism is reconciled in a higher unity; that the best and most complete development of the individual is effected only through parenthood, in due degree--as Spencer, himself childless, formally declared. It is impossible here to show how complete is the evidence for Spencer's law, both from the side of logical necessity and from the side of observation. In order to indicate the overwhelming character of the evidence, one would have to transcribe the whole of his long chapter, and to add to it all our modern knowledge of human birth-rates. This cannot be done, but even without it we may venture to say that people who regard a falling birth-rate as in itself, and obviously, a sign of racial degeneration or immorality, or approaching weakness or failure of any kind, can have made no substantial additions to their knowledge of the subject since they themselves formed items in the birth-rate. Spencer goes on to show, with profound insight, that, in general, greater individuality, or, to put it in other words, the more highly evolved organism, “_though less fertile absolutely, is the more fertile relatively_.” The supreme instance of this truth is, of course, the case of man, in whom individuation has reached its unprecedented height, who is _absolutely_ the least fertile of creatures,[24] and yet who is _relatively_ the most fertile--unique in his actual and persistent multiplication.