It is this way of regarding the matter which has led Dr. Watts to propose an alliance between religion and science, and which produces the arguments one sometimes sees in defence of Christianity against Positivism, drawn from a consideration of the services which Christianity has rendered to the race, and of the gloomy and desolate condition in which its disappearance would leave the world. Tyndall and Huxley do not, however, occupy the position of religious prophets or fathers. They preside over no church or other organization. They have no power or authority to draft any creed or articles which will bind anybody else, or which would have any claims on anybody's reverence or adhesion. No person, in short, is authorized to bring science into an alliance with religion or with anything else. Such "peace and co-operation" as Dr. Watts proposed would be peace and co-operation between him and Professor Tyndall, or between the theologians and the British Association, but "peace and co-operation between science and religion" is a term which carries absurdity on its face. Science is simply a body of facts which lead people familiar with them to infer the existence of certain laws. How can it, therefore, be either at peace or war with anybody, or co-operate with anybody? What Professor Tyndall might promise would be either not to discover any more facts, or to discover only certain classes of facts, or to draw no inferences from facts which would be unfavorable to Dr. Watts's theory of the universe; but the only result of this would be that Tyndall would lose his place as a scientific man, and others would go on discovering the facts and drawing the inferences. In like manner, the supposition that Christianity can be defended against Positivism on grounds of expediency implies a singular conception of the mental operations of those persons who are affected by Positivist theories, and indeed, we might add, of the thinking world generally. No man believes in a religion simply because he thinks it useful, and therefore no man's real adhesion to the Christian creed can be secured by showing him how human happiness would suffer by its extinction. This argument, if it had any weight at all, would only induce persons either to pretend to be Christians when they were not, or to refrain from assailing Christianity, or to avoid all inquiries which might possibly lead to sceptical conclusions. It is therefore, perhaps, a good argument to address to believers, because it may induce them to suppress doubts and avoid lines of thought or social relations likely to beget doubt; but it is an utterly futile argument to address to those who have already lost their faith. Men believe because they are convinced; it is not in their power to believe from motives of prudence or from public spirit.