Mr. Samuel Bailey devotes the last four in his Third Series of 'Letters on the Philosophy of the Human Mind,' to the subject of the Moral Sentiments, or the feelings inspired in us by human conduct. He first sets down five facts in the human constitution, in which moral phenomena originate—

1. Man is susceptible of pleasure and pain of various kinds and degrees.

2. He likes and dislikes respectively the causes of them.

3. He desires to reciprocate pleasure and pain received, when intentionally given by other sentient beings.

4. He himself expects such reciprocation from his fellows, coveting it in the one case, and shunning it in the other.

5. He feels, under certain circumstances, more or less sympathy with the pleasures and pains given to others, accompanied by a proportionate desire that those affections should be reciprocated to the givers.

These rudimentary affections, states and operations of consciousness [he is careful to note that, besides feelings, intellectual conditions and processes are involved in them] are found more or less developed in all, or nearly all the human race. In support of the limitation now made, he adduces what are given as authentic accounts of savages devoid of all gratitude and fellow-feeling; and then goes on to trace the nature and development of moral sentiment from the rudimentary powers and susceptibilities mentioned, in those that do possess them. In doing so, he follows the convenient mode of speech that takes actions for the objects that excite the susceptibilities, although, in reality, the objects are no other than human beings acting in particular ways.

The feelings he supposes to be modified in manner or degree, according as actions are (1) done by ourselves to others, or (2) done to others by others, or (3) done to others by ourselves; i.e., according as we ourselves are the subjects, the spectators, or doers of them.

First, then, he considers our feelings in regard to actions done to us by others, and the more carefully, because these lie at the foundation of the rest. When a fellow-creature intentionally contributes to our pleasure, we feel the pleasure; we feel a liking to the person intentionally conferring it, and we feel an inclination to give him pleasure in return. The two last feelings—liking and inclination to reciprocate, constitute the simplest form of moral approbation; in the contrary case, dislike and resentment give the rudimentary form of moral disapprobation. It is enough to excite the feelings, that the actions are merely thought to be done by the person. They are moral sentiments, even although it could be supposed that there were no other kinds of actions in the world except actions done to ourselves; but they are moral sentiments in the purely selfish form. That, for moral sentiment, mere liking and disliking must be combined with the desire to reciprocate good and evil, appears on a comparison of our different feelings towards animate and inanimate causes of pleasure and pain; there being towards inanimate objects no desire of reciprocation. To a first objection, that the violent sentiments, arising upon actions done to ourselves, should not get the temperate designation of moral approbation and disapprobation, he replies, that such extremes as the passions of gratitude and resentment must yet be identified in their origin with our cooler feelings, when we are mere spectators or actors. A second objection, that the epithet moral is inapplicable to sentiments involving purely personal feeling, and destitute of sympathy, he answers, by remarking that the word moral, in philosophy, should not eulogistically be opposed to immoral, but should be held as neutral, and to mean 'relating to conduct, whatever that conduct may be.' He closes the first head with the observation, that in savage life the violent desire of reciprocation is best seen; generally, however, as he gives instances to show, in the form of revenge and reciprocation of evil.

In the second place, he considers our feelings when we are spectators of actions done to others by others. These form the largest class of actions, but to us they have a meaning, for the most part at least, only as they have an analogy to actions done to ourselves. The variety of the resulting feelings, generally less intense than when we are the subjects of the actions, is illustrated first by supposing the persons affected to be those we love; in this case, the feelings are analogous to those already mentioned, and they may be even more intense than when we ourselves are personally affected. If those affected are indifferent to us, our feelings are less intense, but we are still led to feel as before, from a natural sympathy with other men's pains and pleasures—always supposing the sympathy is not (as often happens) otherwise counteracted or superseded; and also from the influence of association, if that, too, happen not to be countervailed. Of sympathy for human beings in general, he remarks that a certain measure of civilization seems required to bring it properly out, and he cites instances to prove how much it is wanting in savages. In a third case, where the persons affected are supposed to be those we hate, we are displeased when they are made to rejoice, and pleased when they suffer, unless we are overcome by our habitual associations with good and evil actions. Such associations weigh least with rude and savage peoples, but even the most civilized nations disregard them in times of war.