[5.0.0] John Philoponus on Light

John Philoponus (490-570 AD) worked out an original theory of light:

  • According to Philoponus colour and light is subkind of energeia.
  • Light manifests directional.

The following OntoUML diagram presents the theory of light

Philoponus on Light

CLASSDESCRIPTIONRELATIONS
Energeia“light it has been said that Philoponus ‘completely rejects’ Aristotle, turning light from a static to a kinetic phenomenon better suited to the needs of geometrical optics, and changing the meaning of Aristotle’s word energeia in the process.
It is an important contribution to have drawn attention to Aristotle’s innovation here, but I am not sure that the innovation has been rightly understood.
We need to distinguish light from the action of colour. Each can be called an energeia. Light is the state in virtue of which a transparent medium can actually be seen through, whereas in the dark the medium is only potentially seeable-through. This is what Aristotle means, as Philoponus sees, when he calls light the actualised state (energeia, entelecheia) of the transparent.”
Colour“There is also an energeia of colour. Philoponus uses the for something that goes on in the medium between the observer agrees that colour acts on the medium, but he prefers to rather than an energeia (activity).
To his kinesis he applies De generatione animalium speaks of the kinesis as ‘arriving’, distant object, and as ‘taking a straight course’ or ‘being scattered’. “
subkind of
LightLight is the state in virtue of which a transparent medium can actually be seen through, whereas in the dark the medium is only potentially seeable-through. This is what Aristotle means, as Philoponus sees, when he calls light the actualised state (energeia, entelecheia) of the transparent.”
Whatever may be the case about colour, it is made emphatically light does not travel in the sense of affecting one part of Light should rather be thought of as a state in virtue of actually seeable-through…”
subkind of
DirectionalWhat I conclude is that Philoponus does indeed change Aristotle’s theory of light to make it directional in the way it needs to be. On the other hand, he does not introduce travel in the sense of a time-taking process. Nor does he overthrow
Aristotle’s theory of the action of colour on the medium. Instead, he gives to light the same directionality as was already to be found in Aristotle’s account of the action of colour.

Sources

  • SORABJI, RICHARD: “HILOPONUS AND THE REJECTION OF ARISTOTELIAN SCIENCE”, EDITED BY RICHARD SORABJI INSTITUTE OF CLASSICAL STUDIES SCHOOL OF ADVANCED STUDY UNIVERSITY OF LONDON 2010
  • Wildberg, Christian, “John Philoponus”The Stanford Encyclopedia of Philosophy (Winter 2021 Edition, Edward N. Zalta (ed.)

First published: 16/5/2022

 

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