Baroque Optics and the Disappearance of the Observer: From Kepler’s Optics to Descartes’ Doubt

In the seventeenth century the human observer gradually disappeared from\udoptical treatises. It was a paradoxical process: the naturalization of the eye\udestranged the mind from its objects. Turned into a material optical instrument,\udthe eye no longer furnished the observer with genuine representations\udof visible objects. It became a mere screen, on which rested a blurry array\udof light stains, accidental effects of a purely causal process. It thus befell the\udintellect to decipher one natural object—a flat image of no inherent epistemic\udvalue—as the vague, reversed reflection of another, wholly independent\udobject. In reflecting on and trespassing the boundaries between natural and\udartificial, orderly and disorderly, this optical paradox was a Baroque intellectual\udphenomenon; and it was the origin of Descartes’ celebrated doubt—\udwhether we know anything at all