History
In the fifth century BCE, Empedocles postulated that everything was composed of four elements; fire, air, earth and water. He believed that Aphrodite made the human eye out of the four elements and that she lit the fire in the eye which shone out from the eye making sight possible. If this were true, then one could see during the night just as well as during the day, so Empedocles postulated an interaction between rays from the eyes and rays from a source such as the sun.
Around 400 BCE, emission theory was held by Plato.
In about 300 BCE, Euclid wrote Optica, in which he studied the properties of light. Euclid postulated that light travelled in straight lines and he described the laws of reflection and studied them mathematically. He questioned that sight is the result of a beam from the eye, for he asked how one sees the stars immediately, if one closes one's eyes, then opens them at night. Of course if the beam from the eye travels infinitely fast this is not a problem.
In 55 BCE, Lucretius, a Roman who carried on the ideas of earlier Greek atomists, wrote:
The light and heat of the sun; these are composed of minute atoms which, when they are shoved off, lose no time in shooting right across the interspace of air in the direction imparted by the shove. – On the nature of the Universe
Despite being similar to later particle theories, Lucretius's views were not generally accepted and light was still theorized as emanating from the eye.
Ptolemy (c. 2nd century) wrote about the refraction of light, and developed a theory of vision that objects are seen by rays of light emanating from the eyes.
The dispute over the emission and Aristotelian intromission theories of vision began to settle during 11th century when the experiments of the Arabian physicist, Ibn al-Haytham (Alhazen, 965-1039) lent support to the intromissionist theory in his Book of Optics.
Read more about this topic: Emission Theory (vision)
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“History, as an entirety, could only exist in the eyes of an observer outside it and outside the world. History only exists, in the final analysis, for God.”
—Albert Camus (1913–1960)
“In the history of the human mind, these glowing and ruddy fables precede the noonday thoughts of men, as Aurora the sun’s rays. The matutine intellect of the poet, keeping in advance of the glare of philosophy, always dwells in this auroral atmosphere.”
—Henry David Thoreau (1817–1862)
“Bias, point of view, fury—are they ... so dangerous and must they be ironed out of history, the hills flattened and the contours leveled? The professors talk ... about passion and point of view in history as a Calvinist talks about sin in the bedroom.”
—Catherine Drinker Bowen (1897–1973)