A high degree of intellect tends to make a man unsocial.

Reason deserves to be called a prophet; for in showing us the consequence and effect of our actions in the present, does it not tell us what the future will be?

As the biggest library if it is in disorder is not as useful as a small but well-arranged one, so you may accumulate a vast amount of knowledge but it will be of far less value to you than a much smaller amount if you have not thought it over for yourself; because only through ordering what you know by comparing every truth with every other truth can you take complete possession of your knowledge and get it into your power. You can think about only what you know, so you ought to learn something; on the other hand, you can know only what you have thought about.

Rascals are always sociable, more's the pity! and the chief sign that a man has any nobility in his character is the little pleasure he takes in others' company.

Gaiety alone, as it were, is the hard cash of happiness; everything else is just a promissory note.

All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident.

It is only a man's own fundamental thoughts that have truth and life in them. For it is these that he really and completely understands. To read the thoughts of others is like taking the remains of someone else's meal, like putting on the discarded clothes of a stranger.