Some of the admissions made in this paragraph have an important bearing on the theory of natural selection. Far from supposing that fortuitous destruction would have no influence on the course of natural selection, it can be shown that it would have a most disastrous effect. In many cases the destruction comes in the form of a catastrophe to the individuals, so that small differences in structure, whether advantageous or not, are utterly unavailing. Our experience shows us that a destruction of this sort is going on around us all the time, and accounts in large part for the way in which the majority of animals and plants are destroyed. Unless, for example, a seed happen to fall on a place suitable for its growth, it will perish without respect to a slight advantage it may have over other seeds of its kind. Of the thousands of eggs laid by one starfish, chance alone will decide whether one or another embryo is destroyed by larger animals, or if they escape this danger, the majority of them may be carried out to sea, where it will not be of the least avail if one individual has a slight advantage over the others. Darwin admits this, but adds that, if only a thousandth part is developed, yet of those that do survive the best adapted individuals will tend to propagate their kind in larger numbers than the less well adapted. The argument is not, however, so simple as it appears to be on the surface. I pass over, for the present, the apparent inconsequence in this statement that the best adapted individuals will tend to propagate their kind in larger numbers. It is not by any means certain that this is the case. Darwin’s meaning is, however, fairly clear, and can be interpreted to mean this: after the fortuitous destruction has finished, there will be a further competition of the survivors amongst themselves and with the surrounding conditions. In this higher competition, which is less severe, small individual differences suffice to determine the survival of certain individuals. These are, therefore, selected. In this argument it is assumed that a second competition takes place after the first destruction of individuals has occurred, and this presupposes that more individuals reach maturity than there is room for in the economy of nature. But we do not know to what extent this takes place. If only as many mature as can survive, then the second competition does not take place. If, on the other hand, fewer mature than there is room for, then again competition does not take place. And if at all times selection is not rigorously carried out, everything may be lost that has been so laboriously gained. We see then that the result that Darwin imagines would take place, can be carried out only when more individuals reach maturity than there is room for (if it is a case of competition with one another), or that escape their enemies (if it is a question of competition with other forms).