But granting this very obvious remark, what harm does "heredity" do us? It is the most familiar of all remarks that you and I and all of us depend upon our brains in some sense. If they are pierced, we die; if they are inflamed, we go mad; and their constitution determines the whole of our career. A grain of sand in the wrong place, as the old epigrams have told us,--in Cæsar's eye, for example,--may change the course of history. That unlucky fly, which, as Fuller remarks, could find no other place to creep into in the whole patrimony of St. Peter except the Pope's throat, choked the unlucky man, and, for the time at least, altered the ecclesiastical order of Christendom. In other words, we are dependent at every instant upon elements in the outside world,--bacteria, for instance,--and the working of our own physical organism. But, that being so, what conceivable difference does it make whether the brain, which we certainly did not ourselves make, has a fixed resemblance to that of our parents, or be, if it be possible, the product of some other series of processes? It is important, no doubt, to recognise the fact; it would be of the highest importance if we could define the exact nature of the fact; but the influence upon any general ethical doctrine of the recognition of the bare fact itself seems to be precisely nothing at all. It is part of the necessary data of all psychological speculation, and has been recognised with more or less precision from the very first attempts to speculate.