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.

The individual is not accountable to society for his actions in so far as these concern the interests of no person but himself.

Every established fact which is too bad to admit of any other defence is always presented to us as an injunction of religion.

There is one plain rule of life. Try thyself unweariedly till thou findest the highest thing thou art capable of doing, faculties and outward circumstances being both duly considered, and then do it.

Human beings are no longer born to their place in life...but are free to employ their faculties and such favorable chances as offer, to achieve the lot which may appear to them as desirable.

The only part of the conduct of any one, for which he is amenable to society, is that which concerns others. In the part which merely concerns himself, his independence is, of right, absolute. Over himself, over his own body and mind, the individual is sovereign.

The application of algebra to geometry ... has immortalized the name of Descartes, and constitutes the greatest single step ever made in the progress of the exact sciences.