Society and conversation, therefore, are the most powerful remedies for restoring the mind to its tranquillity, if, at any time, it has unfortunately lost it; as well as the best preservatives of that equal and happy temper, which is so necessary to self-satisfaction and enjoyment. Men of retirement and speculation, who are apt to sit brooding at home over either grief or resentment, though they may often have more humanity, more generosity, and a nicer sense of honour, yet seldom possess that equality of temper which is so common among men of the world.

Section I, Chap. III. - The Theory of Moral Sentiments (1759) - Part I