Visual Fire: An Analysis of the Greek Belief in Eye Emission and Its Flaws

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Discussion Overview

The discussion centers on the ancient Greek belief that vision is caused by the emission of "fire" from the eyes, as described in the book "A History Of Optics" by Oliver Darrigol. Participants explore the implications of this belief, its historical context, and its relevance to modern understanding of vision and optics.

Discussion Character

  • Exploratory
  • Historical
  • Debate/contested

Main Points Raised

  • One participant questions the validity of the Greek belief in eye emission, arguing that it contradicts the inability to see in the dark.
  • Another participant suggests that the "fire" may need to reach illuminated surfaces, acknowledging that the model is incorrect by modern standards but was plausible given the knowledge of the time.
  • A participant references Empedocles' view that vision results from both the fire of the eye and sunlight, noting that this perspective alleviates some issues with the original argument but remains flawed by contemporary physics.
  • One participant encourages further reading of modern physics, implying that the historical understanding is outdated.
  • Another participant appreciates the exploration of historical scientific perspectives, suggesting that it can enhance understanding of modern scientific axioms and reasoning.

Areas of Agreement / Disagreement

Participants express a mix of agreement on the historical significance of the belief and disagreement on its validity and implications for modern science. There is no consensus on the correctness of the ancient models versus modern understanding.

Contextual Notes

The discussion highlights limitations in the historical understanding of vision, including assumptions about light and perception that are not aligned with contemporary physics. The relevance of these ancient beliefs to future models remains unresolved.

Who May Find This Useful

Readers interested in the history of science, the evolution of optical theories, and the relationship between ancient and modern scientific thought may find this discussion insightful.

Vinay080
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I am reading the book "A History Of Optics" by Oliver Darrigol, and I came across this sentence (under the heading Visual Fire):
In the Greek popular understanding of the visual process, the eye emits a fire whose rays probe the surface of the observed object
Isn't this a low-quality argument? This can be directly disproved by the fact that humans inbabilty to see in dark, viz. if humans can see things from the "fire" emitted from their eyes, then they can see things in dark. Is this just a bogus argument given push because of its fancy look or was there any strong support for this view?

The question took significance for me, as every concieved principles will be trying to look for generality, and this principle is also concieved to look for generality in explaining things; and I was wondering whether the proper support for this argument has anything to donate for the future development of the nature's explanation.
 
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Maybe the "fire" has to reach surfaces that are lit? It also has to reach red surfaces to give the impression of red...
We know that model is wrong today (and with the knowledge of a finite speed of light it is obvious), but with the limited knowledge back then it was a possible model.
 
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And..breaking news! I continued reading, and came to Empedocles; he is said to believe that the cause of vision to be because of both from the fire of eye and the flame of sun, based on the principle (though not rigorous, but by "analogy" hypothesis) that (quoted from the book)
By Earth in us we percieve earth; by water in us water; by air in us, the gods' air; and consuming fire by fire in us

This lifts up most of the problems on the argument, based on the situation of those days; but understanding still more on their like arguments (if there are any) towards the model will be of interest to the future models (if required).
 
Vinay080 said:
And..breaking news! I continued reading, and came to Empedocles; he is said to believe that the cause of vision to be because of both from the fire of eye and the flame of sun, based on the principle (though not rigorous, but by "analogy" hypothesis) that (quoted from the book)
This lifts up most of the problems on the argument, based on the situation of those days; but understanding still more on their like arguments (if there are any) towards the model will be of interest to the future models (if required).

And this is all still totally wrong in the light of known physics today

I suggest you start reading some more modern physics textbooks, at least 2000 years ahead of what you have been reading

Dave
 
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Vinay080 said:
And..breaking news! I continued reading, and came to Empedocles; he is said to believe that the cause of vision to be because of both from the fire of eye and the flame of sun, based on the principle (though not rigorous, but by "analogy" hypothesis) that (quoted from the book)

This lifts up most of the problems on the argument, based on the situation of those days; but understanding still more on their like arguments (if there are any) towards the model will be of interest to the future models (if required).

Kudos to you!
Reading about and being aware of the history of science and how humans placed themselves and regarded their relationship to the Earth and the cosmos is interesting in itself. Different cultures might have seen themselves in different a different light then others, you may be well aware.

You may have a different perspective on inductive and deductive reasoning, their strengths and weaknesses, from pursuing such an endeavor, other than that gained by studying the popular basic Plato philosophy courses or that stressed in such as geometry and its axioms.

It might give you also a better understanding of the axioms upon which of modern science relies, and whether or not there are some inherent faults or areas that need further investigation.
 
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I suggest you start reading some more modern physics textbooks, at least 2000 years ahead of what you have been reading
:biggrin: I am reading "History" book, which contains all the physics, back from past to present; but I do agree to learn more modern concepts as you suggested, I just happened to read the past theories in that book, and went on analysing their reasoning.

That being said, @256bits has said correctly, on the importance of studying history.
 
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