Farther, as each man has the consciousness of these principles in himself, he has the conviction that similar principles exist in others. Hence arises the impression, that, as he judges of their conduct by his own moral feelings, so will they judge of him by corresponding feelings in themselves. In this manner is produced that reciprocity of moral impression, by which a man feels the opinion of his fellow-men to be either a reward or a punishment; and hence also springs that great rule of relative duty, which teaches us to do to others as we would that they should do to us. This uniformity of moral feeling and affection even proves a check upon those who have subdued the influence of these feelings in themselves. Thus, a man who has thrown off all sense of justice, compassion, or benevolence, is still kept under a certain degree of control by the conviction of these impressions existing in those by whom he is surrounded. There are indeed men in the world, as has been remarked by Butler, in whom this appears to be the only restraint to which their conduct is subjected. Upon the whole, therefore, there seems to be ground for assuming, that the articles of belief, which have been the subject of the preceding observations, are primary principles arising with an immediate feeling of conviction in our moral constitution; and that they correspond with those elements in our intellectual economy, which are commonly called First Truths,--principles which are now universally admitted to require no other evidence than the conviction which forces itself upon every sound understanding. PHILOSOPHY OF THE MORAL FEELINGS. When we analyze the principles which distinguish man as a moral being, our attention is first directed to his actions, as the external phenomena by which we judge of his internal principles. It is familiar to every one, however, that the same action may proceed from very different motives, and that, when we have the means of estimating motives or principles, it is from these that we form our judgment respecting the moral condition of the individual, and not from his actions alone. When we consider separately the elements which enter into the economy of an intelligent and responsible agent, they seem to resolve themselves into the following:-- I. His actual conduct, or actions. II. In determining his conduct, the immediate principle is his will, or simple volition. He wills some act,--and the act follows of course, unless it be prevented by restraint from without, or by physical inability to perform it. These alone can interfere with a man following the determination of his will, or simple volition.