It is in this beneficial influence that we shall find the surest guarantee for morality; for domestic and even for personal morality, as well as for social. For as the whole tendency of Positivism is to induce every one to live as far as possible without concealment, the public will be intrusted with a strong check upon the life of the individual. Now that all theological illusions have become so entirely obsolete, the need of such a check is greater than it was before. It compensates for the insufficiency of natural goodness which we find in most men, however wisely their education has been conducted. Except the noblest of joys, that which springs from social sympathy when called into constant exercise, there is no reward for doing right so satisfactory as the approval of our fellow-beings. Even under theological systems it has been one of our strongest aspirations to live esteemed in the memory of others. And still more prominence will be given to this noble form of ambition under Positivism, because it is the only way left us of satisfying the desire which all men feel of prolonging their life into the Future. And the increased force of Public Opinion will correspond to the increased necessity for it. The peculiar reality of Positive doctrine and its constant conformity with facts facilitate the recognition of its principles, and remove all obscurity in their application. They are not to be evaded by subterfuges like those to which metaphysical and theological principles, from their vague and absolute character, have been always liable. Again, the primary principle of Positivism, which is to judge every question by the standard of social interests, is in itself a direct appeal to Public Opinion; since the public is naturally the judge of the good or bad effect of action upon the common welfare. Under theological and metaphysical systems no appeal of this sort was recognized; because the objects upheld as the highest aims of life were purely personal.