From non-moral resentment we shall pass to the emotion of moral indignation. That this is closely connected with anger is indicated by language itself: we may feel indignant on other than moral grounds, and we may feel "righteous anger." The relationship between these emotions is also conspicuous in their outward expressions, which, when the emotion is strong enough, present similar characteristics. When possessed with strong moral indignation, a person looks as if he were angry,[101] and so he really is, in the wider sense of the term. This relationship has not seldom been recognised by moralists, though it has more often been forgotten. Some two thousand years ago Polybius wrote:--"If a man has been rescued or helped in an hour of danger, and, instead of showing gratitude to his preserver, seeks to do him harm, it is clearly probable that the rest will be displeased and offended with him when they know it, sympathising with their neighbour and imagining themselves in his case. Hence arises a notion in every breast of the meaning and theory of duty, which is in fact the beginning and end of justice."[102] Hartley regarded resentment and gratitude {43} as "intimately connected with the moral sense."[103] Adam Smith made the resentment of "the impartial spectator" a corner-stone of his theory of the moral sentiments.[104] Butler found the essential difference between sudden and deliberate anger to consist in this, that the "natural proper end" of the latter is "to remedy or prevent only that harm which implies, or is supposed to imply, injury or moral wrong."[105] And to Stuart Mill, the sentiment of justice, at least, appeared to be derived from "the animal desire to repel or retaliate a hurt or damage to oneself, or to those with whom one sympathises."[106] [Footnote 101: Notice, for instance, Michelangelo's Moses.] [Footnote 102: Polybius, _Historiae_, vi. 6.] [Footnote 103: Hartley, _Observations on Man_, i. 520.] [Footnote 104: Adam Smith, _op. cit._ _passim_.] [Footnote 105: Butler, _op. cit._ p. 458.] [Footnote 106: Stuart Mill, _Utilitarianism_, p. 79.]