He dwells upon the many advantages of social virtue, of benevolence and friendship, humanity and kindness, of truth and honesty; but confesses that the rule that 'honesty is the best policy' is liable to many exceptions.

He makes us acquainted with his own theory of Happiness.

How little is requisite to supply the _necessities_ of nature?
and what comparison is there between, on the one hand, the cheap pleasures of conversation, society, study, even health, and, on the other, the common beauties of nature, with self-approbation; and the feverish, empty amusements of luxury and expense?
Thus ends the main treatise; but the author adds, in an Appendix, four additional dissertations.
The first takes up the question started at the outset, but postponed, how far our moral approbation is a matter of _reason_, and how far of _sentiment_.

His handling of this topic is luminous and decisive.
If the utility of actions be a foundation of our approval of them, _reason_ must have a share, for no other faculty can trace the results of actions in their bearings upon human happiness.

In Justice especially, there are often numerous and complicated considerations; such as to occupy the deliberations of politicians and the debates of lawyers.
On the other hand, reason is insufficient of itself to constitute the feeling of moral approbation or disapprobation.