“Modern fanaticism thrives in proportion to the quanitity of contradictions and nonsense it poures down the throats of the gaping multitude, and the jargon and mysticism it offers to their wonder and credulity.”

“Or have I passed my time in pouring words like water into empty sieves, rolling a stone up a hill and then down again, trying to prove an argument in the teeth of facts, and looking for causes in the dark, and not finding them?”

“Thus, to give an obvious instance, if I have once enjoyed the cool shade of a tree, and been lulled into a deep repose by the sound of a brook running at its feet, I am sure that wherever I can find a tree and a brook, I can enjoy the same pleasure again. Hence, when I imagine these objects, I can easily form a mystic personification of the friendly power that inhabits them, Dryad or Naiad, offering its cool fountain or its tempting shade. Hence the origin of the Grecian mythology.”

“Half the business of modern education is taken up in learning not to be ignorant; a process peculiarly unfavorable both to strength of mind and pregnancy of imagination...”

“Shall I faint, now that I have poured out the spirit of my mind to the world, and treated many subjects with truth, with freedom, with power, because I have been followed with one cry of abuse ever since for not being a Government tool?”

“The world dread nothing so much as being convinced of their errors.”

“the old maxim... "there are three things necessary to success in life--Impudence! Impudence! Impudence!”