The perpetual obstacle to human advancement is custom.

The guesses which serve to give mental unity and wholeness to a chaos of scattered particulars, are accidents which rarely occur to any minds but those abounding in knowledge and disciplined in intellectual combinations.

Let not any one pacify his conscience by the delusion that he can do no harm if he takes no part, and forms no opinion. Bad men need nothing more to compass their ends, than that good men should look on and do nothing.

Trade is a social act.

Political Economy, in truth, has never pretended to give advice to mankind with no lights but its own; though people who knew nothing but political economy (and therefore knew it ill) have taken upon themselves to advise, and could only do so by such lights as they had.

The general tendency of things throughout the world is to render mediocrity the ascendant power among mankind.

As long as justice and injustice have not terminated their ever renewing fight for ascendancy in the affairs of mankind, human beings must be willing, when need is, to do battle for the one against the other.