The object of science is to discover what we ought to believe, to substitute reasoned knowledge for ignorant conjecture; and the fundamental faith of science is that we ought not to believe anything that is contrary to the uniformity of Nature. Nothing ought to shake our faith in that article of our creed: no amount of evidence will convince a really scientific man, a true believer in the faith, that any alleged violation of the uniformity of Nature can be real. No amount of evidence would be sufficient, for instance, to warrant the belief in miracles. Either the alleged violation is only apparent, and will, with further knowledge, turn out to be a fresh instance of the truth that Nature is uniform; or else the evidence will prove on examination to be untrustworthy. To admit that any evidence could suffice for such a purpose would be to admit that the uniformity of Nature is not the fundamental reality in the world of science, or the ultimate base of our knowledge of what does actually take place in Nature. A little reflection is enough to show that this is an entirely self-consistent line to take up. No amount of evidence can shake what is itself built on no evidence. If the belief in the uniformity of Nature depended on evidence in its favour, then evidence against it might overthrow it. But, as it rests on faith, it is superior to evidence. Now, what is true and self-consistent in the case of science in its own sphere is equally so in the case of morality. It is the common belief of mankind that we can, and are able to, choose what is right; and just as no amount of evidence will convince a really scientific mind that a violation of the uniformity of Nature is possible, so there is no evidence which will convince a really moral man that he could not have done right when he did do what was wrong. "We ought, therefore we can," does not exactly express the facts. Rather, it is the other way: we can love, be merciful, tender, compassionate, therefore we ought. Liberty itself is a law to the free, the source of moral obligation, the gift of Him "whose service is perfect freedom." The pessimist, then, who thinks, by producing evidence, to show that what ought to be cannot be, is adopting in morality a form of argument which in science, when it is a question of miracles, he condemns as inherently vicious and illogical. Further, the evidence which he does produce is not altogether above suspicion. It takes the form of the statement that the uniformity of Nature is a uniformity of necessity and not of a will freely purposing a good end by means of a voluntary uniformity.