In this grand coalition of the public and the private feelings, he sees a decisive illustration of the reference of moral sentiments to the Will.  He farther recognizes in it a solution of the great problem of the relation of virtue to private interest.  Qualities useful to ourselves are raised to the rank of virtues; and qualities useful to others are converted into pleasures.  In moral reasonings, we are enabled to bring home virtuous inducements by the medium of self-interest; we can assure a man that by cultivating the disposition towards other men’s happiness he gains a source of happiness to himself.

The question, Why we do not morally approve involuntary actions, is now answered.  Conscience is associated exclusively with the dispositions and actions of voluntary agents.  Conscience and Will are co-extensive.

A difficulty remains.  ’If moral approbation involve no perception of beneficial tendency, how do we make out the coincidence of the two?’ It might seem that the foundation of morals is thus made to rest on a coincidence that is mysterious and fantastic.  According to the author, the conclusive answer is this.  Although Conscience rarely contemplates anything so distant as the welfare of all sentient beings, yet in detail it obviously points to the production of happiness.  The social affections all promote happiness.  Every one must observe the tendency of justice to the welfare of society.  The angry passions, as ministers of morality, remove hindrances to human welfare.  The private desires have respect to our own happiness.  Every element of conscience has thus some portion of happiness for its object.  All the affections contribute to the general well-being, although it is not necessary, nor would it be fit, that the agent should be distracted by the contemplation of that vast and remote object.

To sum up Mackintosh:—­

I.—­On the Standard, he pronounces for Utility, with certain modifications and explanations.  The Utility is the remote and final justification of all actions accounted right, but not the immediate motive in the mind of the agent. [It may justly be feared, that, by placing so much stress on the delights attendant on virtuous action, he gives an opening for the admission of sentiment into the consideration of Utility.]

II.—­In the Psychology of Ethics, he regards the Conscience as a derived or generated faculty, the result of a series of associations.  He assigns the primary feelings that enter into it, and traces the different stages of the growth.  The distinctive feature of Conscience is its close relation to the Will.

He does not consider the problem of Liberty and Necessity.

He makes Disinterested Sentiment a secondary or derived feeling—­a stage on the road to Conscience.  While maintaining strongly the disinterested character of the sentiment, he considers that it may be fully accounted for by derivation from our primitive self-regarding feelings, and denies, as against Stewart and Brown, that this gives it a selfish character.