To the other side we may put the question somewhat differently. It is agreed that all the many changes which are incessantly taking place in the universe, and which, added together, constitute what is called the cosmic process, are incessantly and inevitably working for good, and themselves are always rising from good to better. But what of the Force, or Power, or Cause, or Reality which underlies them and of which they are the manifestation? May we infer that because they are good, it is good? That if the fruits are good, the tree must be good also? To this the reply will be that it is the manifestations which we know; they alone are known to us; they alone can be known to us. That which underlies them is not manifest; and that which is not manifested to us obviously cannot be known to us: it is the Unknowable. Obviously, therefore, it is impossible for us to say whether it is good or not. To affirm and to deny that it is good would both equally be to profess knowledge of the unknowable. Religion may profess--and, indeed, all religions have professed--to possess this inconceivable and impossible knowledge. But religion is not science. On this view, then, there are limits to the optimism of evolution: to apply the term "good" to that which manifests itself as the cosmic process in evolution is mere illusion. But this raises a further question: If it is unmeaning to call the Unknowable Reality good, what precisely is the meaning and value of the term "good" when applied to those forms in which the Unknowable manifests itself to us? To begin with, it is clear that if everything has been evolved, then our moral aspirations also are the products of evolution. It is they, indeed, that distinguish man from the brute; but even of them the law of continuity holds good: we can see not only how in man the virtues have been developed by civilisation, but we can trace the germs of conscience in that civilised animal the dog, as we can certainly see maternal affection, devotion, and self-sacrifice in the fiercest of undomesticated animals. In other words, the struggle for existence is waged better in co-operation than by individual effort; co-operation implies the subordination of individual impulse to the interests of the species or society; and such subordination, taking different forms in different stages of social development, is what we call virtue.