No simplicity of mind, no obscurity of station, can escape the universal duty of questioning all that we believe.

It is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence.

To sum up: it is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence.

In like manner, if I let myself believe anything on insufficient evidence, there may be no great harm done by the mere belief; it may be true after all, or I may never have occasion to exhibit it in outward acts.

The danger to society is not merely that it should believe wrong things, though that is great enough; but that it should become credulous, and lose the habit of testing things and inquiring into them; for then it must sink back into savagery.

We may always depend on it that algebra, which cannot be translated into good English and sound common sense, is bad algebra.