Date: 1748, 1749

"For if it does not entirely sleep, how little does it want of it? Since it is impossible for her to recollect one object, to which she gave attention, amidst that innumerable crowd of confused ideas, which as so many vanishing clouds had filled up, if I may so say, the atmosphere of the brain."

— Julien Offray de La Mettrie (1709-1751)

Date: 1748, 1749

"And where is the wonder that the body when in health should be subservient, for how can it resist that torrent of blood, and all those spirits which are ready to force obedience, the will having for its ministers an invisible army of fluids, always ready to receive its orders, and as quick as li...

— Julien Offray de La Mettrie (1709-1751)

Date: 1762

"Je méditois donc sur le triste sort des mortels flottant sur cette mer des opinions humaines, sans gouvernail, sans boussole, & livrés à leurs passions orageuses, sans autre guide qu’un pilote inexpérimenté qui méconnaît sa route, & qui ne sait ni d’où il vient ni où il va."

— Rousseau, Jean-Jacques (1712-1778)

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)