What, then, of the environment, of the cosmos, in which man finds himself, in which he has to act and may act so as to advance or not to advance towards the ideal? To begin with, we may distinguish between those forces in the cosmos which man can to some extent control, and those over which he has no control. The former, from this point of view, the point of view of action, are means whereby man secures his ends: his regulation of them effects that adaptation _of_ the environment which, according to Professor Huxley, is essential to ethical progress. Now, as a matter of observed fact, no one doubts that the advance which civilised man has made in controlling the forces of Nature is due to science and to civilised man's devotion to the scientific ideal of truth. Even the savage made what little progress he did make in this direction by acting fitfully and unconsciously, or at the most semi-consciously, on the principle of the uniformity of Nature: the savage was faithful in little things to the scientific ideal--which was revealed to him but dimly--the _savant_ is fully conscious of the principle on which he acts, walks in its light, and strives by example and precept to save his fellow-men from relapsing into the darkness of error and superstition. It is not merely because of the material advantages, the comforts and luxuries, which science indirectly secures to mankind, that the man of science devotes himself to the scientific ideal and seeks to make it universal: it is for the sacred cause of truth. In a word, what at first sight presents itself merely as a principle of the scientific reason, proves, in the conception of those who have spent their lives in endeavouring to seek the scientific ideal and to ensue it, to be a manifestation of the moral reason, to be not merely in harmony with the moral ideal, but to have been its harbinger, making the way straight for it. Belief which implies a violation of the uniformity of Nature is denounced not because it violates a scientific principle, but because it is immoral, a pretence, and a lie. The final cause of science is thus made out to be to subserve the moral ideal, to secure that adaptation of the environment without which ethical progress is impossible. The labour of adapting his environment would have for man as a rational being no sufficient reason if it did not tend to realise his moral ideal. Man may use his science and the power of adapting his environment for other than moral ends; but such use is not, according to this view, progress. In other words, it is not science or the scientific ideal alone which enables us to lay down the line of progress, but science and morality together: one point cannot give us our direction, but the line which connects two points may.