A recluse without books and ink is already in life a dead man.

The truthful man is usually a liar.

One can state, without exaggeration, that the observation of and the search for similarities and differences are the basis of all human knowledge.

The first time I saw nitroglycerine was in the beginning of the Crimean War. Professor Zinin in St. Petersburg exhibited some to my father and me, and struck some on an anvil to show that only the part touched by the hammer exploded without spreading.

I am a misanthrope and yet utterly benevolent, have more than one screw loose yet am a super-idealist who digests philosophy more efficiently than food.

If I have a thousand ideas and only one turns out to be good, I am satisfied.