In Chapter XXIII., the author makes the application of his principles to Ethics.  The actions emanating from ourselves, combined with those emanating from our fellow-creatures, exceed all other Causes of our Pleasures and Pains.  Consequently such actions are objects of intense affections or regards.

The actions whence advantages accrue are classed under the four titles, Prudence, Fortitude, Justice, Benevolence.  The two first—­Prudence and Fortitude [in fact, Prudence]—­express acts useful to ourselves in the first instance, to others in the second instance.  Justice and Benevolence express acts useful to others in the first instance, to ourselves in the second instance.  We have two sets of association with all these acts, one set with them as our own, another set with them as other people’s.  With Prudence (and Fortitude) as our own acts, we associate good to ourselves, either in the shape of positive pleasure, or as warding off pain.  Thus Labour is raised to importance by numerous associations of both classes.  Farther, Prudence, involving the foresight of a train of consequences, requires a large measure of knowledge of things animate and inanimate.  Courage is defined by the author, incurring the chance of Evil, that is danger, for the sake of a preponderant good; which, too, stands in need of knowledge.  Now, when the ideas of acts of Prudence and acts of Courage have been associated sufficiently often with beneficial consequences, they become pleasurable ideas, or Affections, and they have also, from the nature of the case, the character of Motives.  In short, there is nothing in prudential conduct that may not be explained by a series of associations, grounded on our pleasurable and painful sensations, on the ideas of them, and on the ideas of their causes.

The real difficulty attaches to Justice and to Beneficence.

As to Justice.  Men, in society, have found it essential for mutual benefit, that the powers of Individuals over the general causes of good should be fixed by certain rules, that is, Laws.  Acts done in accordance with these rules are Just Acts; although, when duly considered, they are seen to include the main fact of beneficence, the good of others.  To the performance of a certain class of just acts, our Fellow-creatures annex penalties; these, therefore, are determined partly by Prudence; others remain to be performed voluntarily, and for them the motive is Beneficence.

What then is the source of the motives towards Beneficence?  How do the ideas of acts, having the good of our fellows for their end, become Affections and Motives?  In the first place, we have associations of pleasure with all the pleasurable feelings of fellow-creatures, and hence, with such acts of ours as yield them pleasure.  In the second place, those are the acts for procuring to ourselves the favourable Disposition of our Fellow-men, so that we have farther associations of the pleasures flowing from such favourable dispositions.  Thus, by the union of two sets of influences—­two streams of association—­the Idea of our beneficent acts becomes a pleasurable idea, that is, an Affection, and, being connected with actions of ours, is also a Motive.  Such is the genesis of Beneficent or Disinterested impulses.