“Answer me, you who believe that animals are only machines. Has nature arranged for this animal to have all the machinery of feelings only in order for it not to have any at all?”

“Animals have these advantages over man: they never hear the clock strike, they die without any idea of death, they have no theologians to instruct them, their last moments are not disturbed by unwelcome and unpleasant ceremonies, their funerals cost them nothing, and no one starts lawsuits over their wills.”

“If God did not exist, He would have to be invented. But all nature cries aloud that he does exist: that there is a supreme intelligence, an immense power, an admirable order, and everything teaches us our own dependence on it.”

“All men are by nature free; you have therefore an undoubted liberty to depart whenever you please, but will have many and great difficulties to encounter in passing the frontiers.”

“Fools have a habit of believing that everything written by a famous author is admirable. For my part I read only to please myself and like only what suits my taste.”

“It is the triumph of superior reason to live with folks who don't have any.”

“I have received your new book against the human race, and thank you for it. Never was such a cleverness used in the design of making us all stupid. One longs, in reading your book, to walk on all fours. But as I have lost that habit for more than sixty years, I feel unhappily the impossibility of resuming it. Nor can I embark in search of the savages of Canada, because the maladies to which I am condemned render a European surgeon necessary to me; because war is going on in those regions; and because the example of our actions has made the savages nearly as bad as ourselves. [in response to Rousseau's "The Social Contract"]”