Date: 1641

"I am not that structure of limbs which is called a human body. I am not even some thin vapour which permeates the limbs - a wind, fire, air, breath, or whatever I depict in my imagination; for these are things which I have supposed to be nothing."

— Descartes, René (1596-1650)

Date: 1641

"And whenever my preconceived belief in the supreme power of God comes to mind, I cannot but admit that it would be easy for him, if he so desired, to bring it about that I go wrong even in those matters which I think I see utterly clearly with my mind's eye."

— Descartes, René (1596-1650)

Date: 1641

"Now if we are to become aware of something, it is necessary for the thing to act on the cognitive faculty by transmitting its semblance to the faculty or by informing the faculty with its semblance. Hence it seems clear that the faculty itself, not being outside itself, cannot transmit a semblan...

— Gassendi, Pierre (1592-1655)

Date: 1644, 1647

A 'clear' perception is analogous to an object "present to the eye's gaze" that "stimulates it with a sufficient degree of strength and accessibility"

— Descartes, René (1596-1650)