This discontinuity it is which persuades many of us to conceive human life to be not so much a mighty maze without a plan, as a mere stringing of beads on an endless cord of which one end arose in Mother Earth, whilst the other may come at any time--but goes nowhere. The beads, which we call generations, vary in size and colour, no doubt, but on no system; each one makes a fresh start; the average difference between them is merely one of position; and the result is merely to make the string longer. Or the generations might be conceived as the links of an indeterminate chain, necessarily held to each other: but suggesting not at all the idea of a living process such that its every step is fraught with eternal consequence. In a word, we incline to think that History merely goes on repeating itself, and we have to learn that History never repeats itself. Every generation is epoch-making. It is thus to the conception of parenthood as the vital and organic link of life that we are forced: and the whole of this book is really concerned with parenthood. We shall see, in due course, that no generation, whether of men or animals or plants, determines or provides, as a whole, the future of the race. Only a percentage, as a rule a very small percentage indeed, of any species reach maturity, and fewer still become parents. Amongst ourselves, one-tenth of any generation gives birth to one-half the next. These it is who, in the long run, make History: a Kant or a Spencer, dying childless, may leave what we call immortal works; but unless the parents of each new generation are rightly chosen or “selected”--to use the technical word--a new generation may at any time arise to whom the greatest achievements of the past are nothing. The newcomers will be as swine to these pearls, the immortality of which is always conditional upon the capacity of those who come after to appreciate them. There is here expressed the distinction between two kinds of progress: the traditional progress which is dependent upon transmitted achievement, but in its turn is dependent upon racial progress--this last being the kind of progress of which the history of pre-human life upon the planet is so largely the record and of which mankind is the finest fruit hitherto. * * * * * It is possible that a concrete case, common enough, and thus the more significant, may appeal to the reader, and help us to realise afresh the conditions under which human life actually persists.