Date: 1764

"Nobody knows what really is the being called 'spirit', to which even you give the material name of 'spirit', which means wind."

— Arouet, François-Marie [known as Voltaire] (1694-1778)

Date: 1772

"It will remind me of what I used to be, and Pride will have to come to a standstill at the threshold of my heart."

— Diderot, Denis (1713-1784)

Date: 1777

"The minds of the negroes are contracted; because slavery destroys all the springs of the soul."

— Raynal, Guillaume Thomas (1713-1796)

Date: 1780-85; in French, 36 vols. 1749-1788

"Is it difficult to perceive that our ideas originate from our senses alone; that the objects we regard as real existences, are those concerning which the senses uniformly give the same testimony."

— Buffon, Georges Louis Leclerc, comte de (1707-1788)