"There are never in nature two beings, which are precisely alike, and in which it is not possible to find some difference which is internal, or based on some intrinsic quality."

"There are two kinds of truths: those of reasoning and those of fact."

"Nature has established patterns originating in the return of events, but only for the most part. New illnesses flood the human race, so that no matter how many experiments you have done on corpses, yo…"

"There is nothing in the intellect that was not previously in the senses, except the intellect itself."

"I do not believe that a world without evil, preferable in order to ours, is possible; otherwise it would have been preferred. It is necessary to believe that the mixture of evil has produced the great…"