What Makes Light and Color Unique in Our Perception?

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Discussion Overview

The discussion revolves around the nature of light and color perception, particularly focusing on why organisms, including humans, have evolved to detect a specific range of electromagnetic radiation (EMR) known as visible light. Participants explore the properties of EMR, the evolutionary significance of visible light, and the implications of different wavelengths on biological detection mechanisms.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants note that color and light are subjective properties assigned by our brains to the interaction between our eyes and EMR, questioning the evolutionary basis for the limited range of visible light detection.
  • There is a suggestion that different species have evolved to detect various parts of the EM spectrum, with some having good infrared vision.
  • One participant raises the question of whether specific qualities of EMR, such as frequency and amplitude, contribute to the evolutionary development of visual systems.
  • Another participant discusses the structural requirements for detecting different frequencies, suggesting that longer wavelengths like radio waves would require larger structures, which may not have evolved.
  • Some argue that the evolutionary pressures faced by nocturnal versus diurnal animals could explain the development of different visual sensitivities, such as infrared versus color vision.
  • A participant questions why organisms evolved to detect visible light specifically, considering the sun emits a wide range of EMR, and whether the intensity of EMR in the visible range plays a role.
  • Concerns are raised about the potential damaging effects of wavelengths outside the visible spectrum on biological structures, particularly regarding UV and higher frequencies.
  • One participant explains that the intensity of EMR decreases significantly beyond the visible spectrum, contributing to the perception of darkness at higher wavelengths.

Areas of Agreement / Disagreement

Participants express a range of views on the evolutionary significance of visible light detection, with no consensus reached on the specific reasons for this evolutionary adaptation. Multiple competing perspectives on the properties of EMR and their implications for biological detection remain present throughout the discussion.

Contextual Notes

Participants acknowledge the complexity of EMR and its interaction with biological systems, highlighting the need for further exploration of the assumptions underlying their claims about evolutionary pressures and the properties of different wavelengths.

  • #61
Furyan5 said:
We don't actually see light, we see because of light. Our brain doesn't create a visual representation of light itself, for us to perceive. The brain interprets light into sensations such as colors and brightness. It's this we perceive. It's through colors and brightness that we perceive objects. The contrast from its surrounding colors and brightness.
Well, we "see light" in the sense that photons themselves hit photosensors and trigger a response.
 
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  • #62
Furyan5 said:
Are you talking about emotional responses to colors? Or understanding what colors are and how we see them?
Everything in our minds is 'emotional' to some extent. Everything we experience is subjective. We invented Mathematics as a way of communicating in a very formal way and we have agreed on the syntax and 'meanings' it carries. But when we try to communicate any of our sensations to another individual, we are limited to our language or to real life examples (eg red is like strawberries and coke bottles - no use for someone who has seen neither).
We 'understand' (a dodgy word in most contexts and even more so in psychology) that colours can be mimicked and measured up to a point so we can sort of reverse engineer human colour vision. whether or not that involves understanding of the process is questionable. Colour is only really in our heads. Outside of our heads, we can only use a model that can predict reasonably well what colour a human will assign to a given spectral mix on a screen.
 
  • #63
ZapperZ said:
OK, one more time:

1. "Color" is a human invention. It is a sloppy and ambiguous way of characterizing EM radiation.

2. "Wavelength" and "frequency" of EM radiation are more direct, clear, and definitely less ambiguous. So why aren't you including the discussion of different types of EM radiation using such characterizations rather than just using "colors"? It is why I asked if you are only restricting yourself to using the human eye as the sole light detector.

Is this clearer now?

Zz.

The thread is not about whether we detect light or not. Everyone agrees that we detect certain wavelengths. The thread is about whether we perceive light or not. Is the detection of light by the eye called seeing when all other visual perception occurs in the visual cortex. Is detecting light, seeing or only a part of the process which results in seeing. Opinions seem to differ, so I'm seeking clarity, with an explanation, why people believe one or the other.
 
  • #64
The human eye is not a spectrometer and our appreciation of the spectrum of the light we see is only based on a very crude analysis. Only three basic broadband analysis filters have been identified but our vision system makes good use of that data and context to come up with a highly data reduced measure. It's good enough for us to have survived ok and that's all that evolution needs to provide us with.
There is a lot of very sloppy terminology around - even on PF - which refers to the 'wavelength of colours'. I am always surprised that the basics of tristimulus colour vision seem to be too much for many otherwise bright people to take on board.
 
  • #65
russ_watters said:
I'm sorry, but this just doesn't seem very meaningful to me. In order for things to interact (except perhaps in QM), they have to be co-located. So what? Or is that the whole point?
Answered in #64
 
  • #66
Furyan5 said:
The thread is not about whether we detect light or not. Everyone agrees that we detect certain wavelengths. The thread is about whether we perceive light or not. Is the detection of light by the eye called seeing when all other visual perception occurs in the visual cortex. Is detecting light, seeing or only a part of the process which results in seeing. Opinions seem to differ, so I'm seeking clarity, with an explanation, why people believe one or the other.

This does not sound like a physics question. It is more physiological, biological.

Zz.
 
  • #67
Thanks to everyone for participating. This thread is slowly going off-topic, so it is closed.
 

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