In all determinations of morality, this circumstance of public utility is ever principally in view; and wherever disputes arise, either in philosophy or common life, concerning the bounds of duty, the questions cannot, by any means, be decided with greater certainty, than by ascertaining, on any side, the true interests of mankind. If any false opinion, embraced from appearances, has been found to prevail; as soon as farther experience and sounder reasoning have given us juster notions of human affairs, we retract our first sentiment, and adjust anew the boundaries of moral good and evil.

Custom, then, is the great guide of human life. It is that principle alone, which renders our experience useful to us, and makes us expect, for the future, a similar train of events with those which have appeared in the past.

All knowledge resolves itself into probability. ... In every judgment, which we can form concerning probability, as well as concerning knowledge, we ought always to correct the first judgment deriv'd from the nature of the object, by another judgment, deriv'd from the nature of the understanding.

On the theory of the soul's mortality, the inferiority of women's capacity is easily accounted for: Their domestic life requires no higher faculties either of mind or body. This circumstance vanishes and becomes absolutely insignificant, on the religious theory: The one sex has an equal task to perform as the other: Their powers of reason and resolution ought also to have been equal, and both of them infinitely greater than at present.

It affords a violent prejudice against almost every science, that no prudent man, however sure of his principles, dares prophesy concerning any event, or foretell the remote consequences of things.

Nothing is pure and entire of a piece. All advantages are attended with disadvantages. A universal compensation prevails in all conditions of being and existence.

Everything is sold to skill and labor; and where nature furnishes the materials, they are still rude and unfinished, till industry, ever active and intelligent, refines them from their brute state, and fits them for human use and convenience.