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Comment by iainmerrick | Hacker News Reader

Modern scientific theories do not explain experiences of colour by appealing to the colours of objects, but instead in terms of objects’ dispositions to reflect, refract, or emit light across different parts of the electromagnetic spectrum. The conclusion that many have drawn is that we either need to identify colours with the physical properties of things that cause our colour experiences, or admit—like Galileo—that colours do not exist.

Explaining colour in terms of how objects reflect, refract or emit different wavelengths of light (and similarly for the rods and cones in our eyes) sounds perfectly satisfactory to me. What's the problem with that theory?

I really don't see the point of all the metaphysical stuff. It just doesn't tell you anything useful.

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Dispositional properties are just as difficult metaphysically than any other type of property.

What's an example of an object property that is philosophically or metaphysically straightforward?

I'm not sure about straightforward but, as an example, temperature seems simpler than colour.

Not so fast. By the time you rope in the notions of absolute zero, entropy, and Maxwell's demon, you could kick up enough dust to keep a whole stable of grad students busy.

These debates are less about a clear and present problem, than a mode of inquiry asking to look again at something "familiar" in a different way.

Partly I'm playing devil's advocate here, as I'm sure there is a good answer... Can you give me an example of a useful, positive contribution that metaphysics and/or philosophy (I confess I don't know what the distinction is between them) have contributed to these topics?

For example, ancient Greek philosophers made many speculations about the nature of atoms, and in some ways their guesses were correct, but I don't think that speculation was especially fruitful. But their advances in geometry and number theory were tremendously productive.

> For example, ancient Greek philosophers made many speculations about the nature of atoms, and in some ways their guesses were correct, but I don't think that speculation was especially fruitful.

In terms of finding the actual answer (at least to the extent that we know the answer), it probably wasn't; but, in terms of suggesting that the question was one that had an answer, I think it was enormously fruitful. Leon Lederman's wonderful book "The God particle" persuasively (if perhaps slightly tongue-in-cheek?) argues a very direct intellectual through-line from the Greek analyses to (then-)current particle physics.

(Having said this, my personal feeling is that philosophy has done its part by expanding the scope of scientific inquiry, but probably doesn't have much to add to modern-day scientific discourse; but, then again, I am a scientist, and so am pre-disposed to believe in the primacy and importance of my discipline.)

> I'm not sure about straightforward but, as an example, temperature seems simpler than colour.

At least physically, this seems wrong to me. Temperature is an emergent property of systems—there is no such thing as the temperature of an isolated particle—whereas (as spectral analysis shows) even individual atoms have colour.

2% of the population perceive a 4th primary color.

  Do you know what it looks like? 
  Can you imagine what it looks like? 
  Can Maxwell's equations predict what it looks like?

I think what's needed to help us imagine that is art and literature, not philosophy.

Biologists hypothesize that Mantis shrimps perceive 12 primary colors. Do you expect a sea creature the size of my fist to share art and literature about its inner experience?

A biologist can explain the workings of the mantis's vision system, an artist can imagine what it might be like to be experience it. What does the philosopher contribute? (I'm not asserting there's no contribution, I'd just like someone to explain what it is.)

The scientist, artist, and philosopher have contributed jack squat. Actually, that's wrong. The scientist has contributed the appearance of knowledge where none exists. I.e. a delusion. The delusion is that modern science understands color. It indeed understands optics, but not color.

The Problem of Color is a subset of the Hard Problem of Consciousness. Both are uncharted territory. Maybe one day we'll have a half-decent theory of color. When that day comes, it will probably bud-off and begin a field of study distinct from "philosophy proper". Just like math and science budded-off. In the meantime, the only thing we can do is imagine and philosophize. Because we don't understand how to even investigate the problem, let alone solve it. We're still at the stage analogous to when the Ancient Greeks were debating whether matter is continuous or discrete. "Nobody knows for sure, but matter sure feels continuous to me."

The least we can do is demarcate our ignorance. Which is why blogposts like this exist. So when you (essentially) say "Our current theory of optics sounds perfectly satisfactory", you are defending the delusion the blogpost meant to correct. My two previous comments aren't meant to contribute a theory of color, but to make obvious that optics and color are not the same thing.

The Problem of Color is a subset of the Hard Problem of Consciousness.

That's a good summary of what the article seems to be saying. But I still don't understand the reasoning behind that claim.

I mean, from the article:

But can this really be right? Focus on a colour in your immediate environment and ask yourself whether that could really be only a figment of your mind, or at best radically different from the way it appears.

Yes, obviously? What's the problem?

Somewhat analogously, there's a whole world of scent and pheromones that most animals perceive strongly, but we barely perceive at all. An entire sense that we don't even realise we're missing! I think that's fascinating, but it doesn't lead me to question the nature of reality in any deep philosophical way. Should it?

Philosophy divides the mystery of consciousness into two problems. The Soft Problem is "how does the brain compute things?". The Hard Problem is "how does qualia exist?".

The Soft Problem is easy to imagine. Neuroscience will solve it eventually. We may not understand it yet, but we can make a lot of computer analogies and educated guesses. After all, computers are already Philosophical Zombies (someone who passes the Turing Test, yet in no way experiences qualia).

> but it doesn't lead me to question the nature of reality in any deep philosophical way. Should it?

Here's the contention the professionals are currently debating. The Hard Problem challenges our notions of Physicalism (as opposed to say, Dualism). "But souls are dumb, Science says so!".

Extrapolate into the future. Even after Neuroscience solves the brain's circuitry, qualia will remain just as mysterious as ever. E.g. suppose we discover that the hippocampus demultiplexes memories to different parts of the brain. Suppose we learn how to directly manipulate memory. Not only can we fix amnesia, but we can implant false memories. "Hooray, we've solved the Soft Problem!". But we still have no leads on the Hard Problem. A hippocampus doesn't distinguish a Homunculus from a P-Zombie.

Physicalism has been so successful in the sciences, everyone takes its accuracy for granted. I myself consider Physicalism true. But Physicalism is not adequate to explain the Hard Problem. This doesn't mean we have to go back to souls. But it does mean we need to (at least) "spice up" Physicalism, or maybe choose another line of attack, etc if we're ever to crack the Hard Problem.

It seems to me that philosophy has made zero progress on the hard problem, other than naming it. Is there any concrete progress, any useful result you can point me at?

Neuroscience and computer science obviously haven't solved it either, but they have at least made some progress in understanding parts of the brain's structure, and gradually reproducing what we thought were uniquely human abilities with mindless computer programs. This suggests that "qualia" may not really be needed to explain consciousness (or at any rate thought); just as Darwin's theories showed why "god" isn't strictly needed to explain the diversity of animal species.

I agree there's still the niggling issue of "but why do I seem to experience stuff? Surely I'm not a mindless automaton!" There's also the problem of "but why does the universe exist in the first place?" But I don't believe philosophers have any particular insight or knowledge to bring to the first problem, any more than theologians have any real inside knowledge of the latter.

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