“Let education kindle only those which are truly beneficialto the human species; let it favour those alone which are really necessary to the maintenance of society. The passions of man are dangerous, only because every thing conspires to give them an evil direction.”

“The only thing necessary for evil to conquer is for us and those like us to do nothing.”

“If only the Geologists would let me alone, I could do very well, but those dreadful Hammers! I hear the clink of them at the end of every cadence of the Bible verses”

“Let us study things that are no more. It is necessary to understand them, if only to avoid them.”

“The only lies for which we are truly punished are those we tell ourselves.”

“The necessary consequence of man's right to life is his right to self-defense. In a civilized society, force may be used only in retaliation and only against those who initiate its use. All the reasons which make the initiation of physical force an evil, make the retaliatory use of physical force a moral imperative.If some "pacifist" society renounced the retaliatory use of force, it would be left helplessly at the mercy of the first thug who decided to be immoral. Such a society would achieve the opposite of its intention: instead of abolishing evil, it would encourage and reward it.”