Saussure in his theory of signs declared that there was no necessary connection between the semantic value of a word and its phonetic sign: the sign 'dog' signifies the physical dog, but in principle (if not possible in practise) we can have the sign 'xog' signify it instead.

Similarly, there appears to be no necessary connection between the physical sensation of the colour blue - its qualia - and its physical correlative, a certain wavelength of light. A video camera capable of 'false colouring' is sufficient to demonstrate this.

Given that there is no necessary connection; can we say that we have a theory of the colour blue? A theory of colour should be necessary, and not contingent.

Further, words do not stand by themselves in atomic isolation establishing no relationships with any others; for example the word (or signs) murder, morder, mourir, morbid and mortal show some affinity with each other. Similarly we do not the colour blue in isolation, our organic affinity with each other is the guarantee (with exceptions) that when I see the colour blue, a man in Borneo, or Papua New Guinea sees it too; or for that matter a vestal virgin in the Rome of Roman Antiquity.

This allows, possibly a test of the theory of the colour blue; at least in a kind of Gedanken-experiment.

Assuming that there is actually life elsewhere, which isn't a completely controversial proposition today, and for the purposes of this question, say on Mars; how can we guarantee that a Martian (unblemished and unflawed) who can see the same visible spectrum that we do (in principle easily determinable) actually see the same colour that we do?

I'd suggest that this test can serve at least as a falsifying test - is this right?

  • Karl Popper..the very archenemy of Marx, of course I read some of his works but after 15 years I haven't remembered anything at all he said was, probably he did not leave significant impact on me....( No offense to YOU ). So you are saying Popper's falsifying test, without which anything can not be proven according to Popper, first of all how do you know that a Martian has an eye or whatever the organism that can discern the "might-be-blue-color" or spectrum? Should this too be done his falsifying ( and scientific ) test?
    – user13955
    Mar 23 '15 at 3:25
  • Please forget if I sound you playing with words. But if someone, really some another human being observe the spectrum differently, then, the discussion will definitely occur, and the name blue, sure, will change I think per your context. And what is wrong with it? For example, Husserl and even Engels said the phenomenon of the target object could change in the course of human being's history.
    – user13955
    Mar 23 '15 at 3:34

We can have a theory of the-properties-of-light-in-the-wavelength-range-that-Humans-call-blue, a theory of human-sensation-when-presented-with-light-in-this-range, a theory of the-emotional-effects-of-this-color-of-light-on-octopuses, and so on. All these are testable in a Popperian sense because they make predictions and you can do experiments to test those.

Having a theory of blue is problematic not because the theory is problematic but because the identifier blue is problematic due to its entanglement with the human experience. Your Martian experiment, if done, would only disprove theories that said something like, "Every conscious being perceives blue in the same way", which I'm pretty sure is disproved already by various animals (e.g. birds, who have different sets of color receptors).

So, we can develop a theory-of-how-humans-see-blue now, and once we find Martians we can create an alternate theory for their blue-perception.

Except we can't actually create a fully compelling thoery now because we don't have the tools to measure human brain activity in the needed level of detail. We already do have quite good theories of how our photoreceptor cells in our eyes are stimulated by blue light (actually, inhibited, causing them to send less signal when they are exposed to blue light), and we have a decent idea of how that information of blueness is represented in V1, the portion of our brains devoted to low-level image processing. That's about as far as we've gotten.

So we don't actually know if we'll be able to make it all the way to qualia. There are some reasons it might not work very well as a general theory. For example, it is possible that our high-level mental representations like "blue" and "hilarious" (both in abstraction and the associated qualia) are actually specialized for our own brains, making them in detail not comparable from person to person, but only comparable in the way we already do: I use my blue-token to denote blue, and so do you, but my blue-token is an arbitrary color-qualia-token from among all the possibilities, and so is yours, and you and I just happen to have linked up V1 cells saying "this is blue" with these tokens.

But, at least assuming technology and science continues to progress in remarkable ways, there's no barrier to having some tested theory that tells us what is actually going on with our experience of blueness.

  • I'm aware of all the theories of the colour blue in the senses you mentioned, but not in any detail; they're unproblematic, as you've noted - and which is why I'm not asking about them; I'm specifically interested in the correlation between the objective phenomena and its subjective correlative - or 'entanglement' as you call it; its this what I'm calling 'a theory of the colour blue'; what I'm asking about is how to we determine that a subject experiences the colour blue? Jan 21 '15 at 13:44
  • Perhaps I haven't explained my question clearly enough; the reason for my choice of a martian is to remove any organic contiguity with the human experience; after all birds are evolutionary related to human beings...and one can use that contiguity to decide whether they have the same experience - ie by the looking closely at their biology/physiology and biochemistry; and relating that to our own experience. Jan 21 '15 at 13:46
  • What I'm asking for is a test which says given subjects A & B and stimulus a & b; that they experience the same colour; I'm asking whether this is a falsifiable popperian test. Jan 21 '15 at 13:48
  • Finally, your last sentence about 'we can develop a theory-of-how-humans-see-blue now' is in slight opposition with your earlier claim 'having a theory of blue is problematic'. Jan 21 '15 at 13:49
  • @MoziburUllah - I amended my answer.
    – Rex Kerr
    Jan 21 '15 at 17:49

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