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In his De Anima (On the Soul), Aristotle writes, "And Empedocles was not correct, nor was anyone else who may have spoken as he did, in speaking as if light is in motion with respect to place and sometimes comes to be located between the earth and what surrounds it, but that such motion escapes our notice. For this is both contrary to the lucidity required of speech and contrary to the appearances. For while it might escape notice in a small interval, that it should escape notice [that light is traveling] from the region of sunrise to that of sunset is too big an assumption." (Book II, ch. 7, 418b) (Aristotle raises and discusses the question of whether light is in motion with respect to place also in On Sense Perception and the Perceptibles, 446a20-447a11.)

Aristotle seems to suggest that if light is indeed so fast that its motion escapes our notice, one would have a hard time accounting for what is responsible for light as it appears to us. Are modern scientists able to offer such an accounting? It seems they are unable to say with clarity whether light, as they understand it, consists of discrete particles or is a continuous wave, or if it is both (or neither), how that is possible.

user132918
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One would answer to an ancient Greek (or all ancients at that) since we have measured the speed of light, the question is moot.:

The first true measurement of the speed of light came in 1676 by a fellow named Ole Roemer (Rømer). Roemer was observing Jupiter's moon Io, the innermost of the Galilean satellites. As seen by an observer on Earth, Io suddenly disappears when it moves into Jupiter's shadow, and it suddenly reappears when it moves out of Jupiter's shadow (back into the sunlight). Roemer was interested in predicting the times at which Io would be observed to emerge from Jupiter's shadow. His goal was to use those observations to determine Io's orbital period more accurately; he was not initially trying to determine the speed of light.

Based on these observations, Roemer calculated that it would take light about 22 minutes to cross the diameter of Earth's orbit. Combining that value with earlier measurements of the Earth's semimajor axis (orbital radius) (described here and here) gives a speed of light of about 210,000 kilometers per second. This is about 30% lower than the modern value for the speed of light, but considering its antiquity, method of measurement, and 17th century uncertainty in the exact sizes of the planetary orbits, this value is remarkably close to the modern value of 299,792.458 kilometers per second.

anna v
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It seems to be both a particle and wave - light has wavelike properties as exhibited by phenomenon of interference. Light also seems to have the properties of a particle as exhibited in the photoelectric effect. That said, I am not sure how modern physics answers how light appears to the "unarmed" eye. Why would modern physics need to explain this given that it has calculated the speed of light at a quantity not easily "observable."

Also see:

https://www.google.com/amp/phys.org/news/2015-03-particle.amp

T Ye
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