Crime is to the passions what nervous fluid is to life: it sustains them, it supplies their strength.

Happiness is ideal, it is the work of the imagination.

Cruelty, very far from being a vice, is the first sentiment Nature injects in us all. The infant breaks his toy, bites his nurse's breast, strangles his canary long before he is able to reason; cruelty is stamped in animals, in whom, as I think I have said, Nature's laws are more emphatically to be read than in ourselves; cruelty exists amongst savages, so much nearer to Nature than civilized men are; absurd then to maintain cruelty is a consequence of depravity. . . . Cruelty is simply the energy in a man civilization has not yet altogether corrupted: therefore it is a virtue, not a vice.

Get it into your head once and for all, my simple and very fainthearted fellow, that what fools call humanness is nothing but a weakness born of fear and egoism; that this chimerical virtue, enslaving only weak men, is unknown to those whose character is formed by stoicism, courage, and philosophy.

Virtue can procure only an imaginary happiness; true felicity lies only in the senses, and virtue gratifies none of them.

If Nature denies eternity to beings, it follows that their destruction is one of her laws. Now, once we observe that destruction is so useful to her that she absolutely cannot dispense with it from this moment onward the idea of annihilation which we attach to death ceases to be real what we call the end of the living animal is no longer a true finish, but a simple transformation, a transmutation of matter. According to these irrefutable principles, death is hence no more than a change of form, an imperceptible passage from one existence into another.

Certain souls seem hard because they are capable of strong feelings, and they sometimes go to rather extreme lengths; their apparent unconcern and cruelty are but ways, known only to themselves, of feeling more strongly than others.