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Left and Right - Definitely defineable

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masterfroggy
758737.  Mon Nov 08, 2010 12:09 pm Reply with quote

Flash wrote:
Well, that's got potential as a way of developing this discussion. I was trying to think of other examples and could only come up with left/right analogues like east/west and clockwise/anti-clockwise. Might be fun to see what else we can think of. RichyT will get us started ...
Try to explain/define colour, to a person who sees colour differently. For example pink, without referencing any other colour

 
Flash
758740.  Mon Nov 08, 2010 12:22 pm Reply with quote

Yes, I did think of that. Of course it isn't possible to convey the subjective impression of (eg) red even between humans - I don't know whether the red you see is the same as the red I see, or not. But I don't think this really ticks the box for present purposes; it would be easy enough to explain to the aliens that we have sensory organs which can differentiate wavelengths of light, and to say which band we designate as "red". That would be an unambiguous explanation of what "red" means (rather than what it feels like - which is inexplicable, I agree).


Last edited by Flash on Mon Nov 08, 2010 12:26 pm; edited 1 time in total

 
masterfroggy
758741.  Mon Nov 08, 2010 12:24 pm Reply with quote

Flash wrote:
Yes, I did think of that. Of course it isn't possible to convey the subjective impression of (eg) red even between humans - I don't know whether the red you see is the same as the red I see, or not. But I don't think this really ticks the box for present purposes; it would be easy enough to explain to the aliens that we have sensory organs which can differentiate wavelengths of light, and to say which band we designate as "red".
I don't see red, so explain red to me,

 
Flash
758744.  Mon Nov 08, 2010 12:28 pm Reply with quote

Red is light with a wavelength of about 630740nm.

(Incidentally, I snuck an extra sentence into the previous post while you were replying.)

 
aTao
758763.  Mon Nov 08, 2010 1:16 pm Reply with quote

Never mind the red you see being different from the red I see. My left eye sees sky blue as a different shade than my right eye, I do however have exceptional colour vision.

 
RichyT
758770.  Mon Nov 08, 2010 1:53 pm Reply with quote

Even disregarding that "red" isn't really about a wavelength of light, you're assuming that the alien has a concept of light, electromagnetism, frequencies and a whole raft of other things that are not as much a "given"as you'd think.

 
RLDavies
758774.  Mon Nov 08, 2010 2:10 pm Reply with quote

aTao wrote:
Never mind the red you see being different from the red I see. My left eye sees sky blue as a different shade than my right eye, I do however have exceptional colour vision.

My left and right eyes have noticeably different colour vision. The left eye sees everything with a yellow cast, and the right one blue. With both eyes open, they average out into "real" colours.

 
Flash
758788.  Mon Nov 08, 2010 2:38 pm Reply with quote

RichyT wrote:
Even disregarding that "red" isn't really about a wavelength of light, you're assuming that the alien has a concept of light, electromagnetism, frequencies and a whole raft of other things that are not as much a "given"as you'd think.

Not really - I've just left those bits out of the post. The concepts you mention are all readily explicable, but spelling them all out here would have turned a one-liner into a monumental tome.

But, for goodness' sake let's not disregard that
Quote:
"red" isn't really about a wavelength of light
- I genuinely thought it was, and look forward to being put right.

 
Posital
758850.  Mon Nov 08, 2010 6:03 pm Reply with quote

Red's a quality of the object/world you perceive (in your head)...

Light is just something we've invented to explain the experience.

This is all we can say if there is no shared experience/reality.

 
Flash
758861.  Mon Nov 08, 2010 6:27 pm Reply with quote

Well ... the subjective experience of "red" (or "pain" or "hope" or "dissonance" or any other personal experience) is inexplicable, of course. We couldn't even explain it fully to ourself, let alone to anyone else (and still less to an alien). Nobody would disagree with that, I think. But to suggest that light was invented by humans ... on the face of it, that assertion doesn't make a whole lot of sense, and you might need to flesh it out a bit IMHO.

 
Leith
758869.  Mon Nov 08, 2010 6:52 pm Reply with quote

Flash wrote:
But, for goodness' sake let's not disregard that
Quote:
"red" isn't really about a wavelength of light
- I genuinely thought it was, and look forward to being put right.


I don't know the full story, but Daniel Dennett appears to touch on this in "Consciousness Explained":

Daniel Dennett wrote:
Many have noticed that it is curiously difficult to say just what properties of things in the world colors could be. The simple and appealing idea - still found in many elementry discussions - is that each colour can be associated with a unique wavelength of light, and hence that the property of being red is simply the property of reflecting all the red-wavelength light and absorbing all the other wavelengths. But this has been known for quite some time to be false. Surfaces with different fundamental reflective properties can be seen as the same color, and the same surface under different conditions of lighting can be seen as different colors. The wavelengths of the light entering the eye are only indirectly related to the colors we see objects to be.

Among others, he refers in turn to C. L. Hardin's book, "Color for Philosophers: Unweaving the Rainbow", excerpts from which can be found on Google books, here.

 
Posital
758877.  Mon Nov 08, 2010 7:26 pm Reply with quote

Flash wrote:
But to suggest that light was invented by humans ... on the face of it, that assertion doesn't make a whole lot of sense, and you might need to flesh it out a bit IMHO.
It goes back to Descartes... if we don't have a shared reality, then the world around us is constructed (invented).

I can't prove that light exists - but I have "invented" it as it makes it easier to understand all those strange impulses entering my cranium - unfortunately I've also had to "invent" a coalition government for the same reason.

But then, how could you possibly share this strange reality...?

Since you can't possibly exist either...

 
mckeonj
758882.  Mon Nov 08, 2010 7:36 pm Reply with quote

The human eye, but one of many different 'eyes' on this planet, is adapted to see a narrow band of wavelengths which are allowed through the atmosphere of this planet, from a very broad band of wavelengths emitted by our sun and other stars and things.
Our eye/brain image processing system 'chooses to see' different wavelengths as different colours. We call this the 'visible spectrum', and are generally agreed that 'red' is at one end, 'green' is in the middle, and 'blue' is at the other end.
We also agree that 'black' is the absence of transmitted or reflected light.
One of the tools of science is the 'black body'; a box about one metre side, painted matt black inside, with a small hole in one side. The hole is the 'black body', which will emit radiation if the temperature of the box is above absolute zero. There are artificial eyes which can 'see' this 'black light'.
The question is: what colour is the 'black body'?

A similar question can be asked of a black bird, or a black cat, or the little black dress worn by milady. In reality, it is impossible to make a truly black dye, the feathers of a black bird are dark grey, with green and purple irridescence, and our black cat is dark grey with a hint of ginger stripes and a tiny tuft of white.

What a load of old cobblers! but I'll post it anyway.

 
mckeonj
758886.  Mon Nov 08, 2010 7:59 pm Reply with quote

Just thinking about trying to establish 'left and right' with aliens.
It's a bit like colour, and time; it is a purely human construct, because we have 'two of everything down the outside and one of everything down the middle' (Ken Dodd)
Suppose our aliens were Ramans (Renezvous with Rama: Arthur C Clarke)
The Ramans did everything in threes, triple airlocks, three legged servos, etc etc. For them, left and right had no meaning, but rotation sense was meaningful; i.e. the servos whirled clockwise to move toward something, and anti-clockwise to move away.
I can't recall whether Clarke discussed the chemistry of Rama; but Lewis Carroll has Alice observe that Looking Glass milk would not be good for you. Note that human world chemistry is dextro-rotatory, so Alice was quite correct.

PS I am feeling feverish, so may not be making sense at the moment.

 
RichyT
758904.  Tue Nov 09, 2010 12:15 am Reply with quote

Flash wrote:
The concepts you mention are all readily explicable, but spelling them all out here would have turned a one-liner into a monumental tome.


I disagree. I think that the more you try to explain, the more you will expose layers of assumed common experience, like an onion.

But yes, to go that route would be somewhat monumental so I am happy to agree to disagree and allow others to make up their own minds.

Besides, my point is not that you can't explain such things but that if you can explain them, you can go on to explain left and right. However, before 1958, we had no evidence that such a thing was possible and no way to explain it.

 

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