Accordingly, France Had Voltaire, and his school of negative thinkers, and England (or rather Scotland) had the profoundest negative thinker on record, David Hume: a man, the peculiarities of whose mind qualified him to detect failure of proof, and want of logical consistency, at a depth which French skeptics, with their comparatively feeble powers of analysis and abstractions stop far short of, and which German subtlety alone could thoroughly appreciate, or hope to rival.

There is always need of persons not only to discover new truths, and point out when what were once truths are true no longer, but also to commence new practices, and set the example of more enlightened conduct, and better taste and sense in human life.

In proportion to the development of his individuality, each person becomes more valuable to himself, and is therefore capable of being more valuable to others. . . .

... the besetting danger is not so much of embracing falsehood for truth, as of mistaking a part of the truth for the whole.

A being who can create a race of men devoid of real freedom and inevitably foredoomed to be sinners, and then punish them for being what he has made them, may be omnipotent and various other things, but he is not what the English language has always intended by the adjective holy.

If opponents of all important truths do not exist, it is indispensable to imagine them and supply them with the strongest arguments which the most skillful devil's advocate can conjure up.

It's hardly possible to overstate the value, in the present state of human improvement, of placing human beings in contact with other persons dissimilar to themselves, and with modes of thought and action unlike those with which they are familiar. Such communication has always been... one of the primary sources of progress.