Marquis de Sade 

It is always by way of pain one arrives at pleasure.

All universal moral principles are idle fancies.  

Lust's passion will be served; it demands, it militates, it tyrannizes.

Are not laws dangerous which inhibit the passions? Compare the centuries of anarchy with those of the strongest legalism in any country you like and you will see that it is only when the laws are silent that the greatest actions appear.

Destruction, hence, like creation, is one of Nature's mandates.

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

Happiness lies neither in vice nor in virtue; but in the manner we appreciate the one and the other, and the choice we make pursuant to our individual organization.

I've already told you: the only way to a woman's heart is along the path of torment. I know none other as sure.

Lust is to the other passions what the nervous fluid is to life; it supports them all, lends strength to them all ambition, cruelty, avarice, revenge, are all founded on lust.  

My manner of thinking, so you say, cannot be approved. Do you suppose I care? A poor fool indeed is he who adopts a manner of thinking for others!

Nature has not got two voices, you know, one of them condemning all day what the other commands.