Man can sin against nature in two ways. First, when he sins against his specific rational nature, acting contrary to reason. In this sense, we can say that every sin is a sin against man's nature, because it is against man's right reason.
A man does not always choose what his guardian angel intends.
By nature all men are equal in liberty, but not in other endowments.
Moral science is better occupied when treating of friendship than of justice.
Sorrow can be alleviated by good sleep, a bath and a glass of wine.
For those with faith, no evidence is necessary; for those without it, no evidence will suffice.