Originality is the one thing which unoriginal minds cannot feel the use of.

It is historically true that a large proportion of infidels in all ages have been persons of distinguished integrity and honor.

It is not the feeling sure of a doctrine (be it what it may) which I call an assumption of infallibility. It is the undertaking to decide that question for others, without allowing them to hear what can be said on the contrary side. And I denounce and reprobate this pretension not the less, if put forth on the side of my most solemn convictions.

There is nothing which an untrained mind shows itself more hopelessly incapable, than in drawing the proper general conclusions from its own experience. And even trained minds, when all their training is on a special subject, and does not extend to the general principles of induction, are only kept right when there are ready opportunities of verifying their inferences by facts.

The test of real and vigorous thinking, the thinking which ascertains truths instead of dreaming dreams, is successful application to practice.

A person may cause evil to others not only by his actions but by his inaction, and in either case he is justly accountable to them for the injury.

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.