Posted: Aug 12, 2017 10:21 am
by zoon
romansh wrote:
GrahamH wrote:
romansh wrote:
GrahamH wrote:I think I'm with SoS on this. 'physical colour', the physics of light and bus and visual system is a reliable discriminator of colour. The 'my red is like your red' spook inner mental world stuff is probably illusion. The bus isn't an illusion.

Well I agree our perception of 'colour' is a reasonable discriminator of colour (or at least photon wavelengths) . That was never an issue.

Sorry, I'm lost. I don't know what you are asking.

In this post I was not asking anything. Just agreeing that our vision has a reasonable colour discrimination. And also pointing out this was never an issue at least not for this thread.

So this whole thing started when I claimed, much as the gentleman in your video, that colour was an illusion.

Perhaps, whether or not something counts as an illusion depends on whether one is deceived by it. For example, if a shop has a back wall which is a large mirror, and someone who doesn’t know that shop walks in, then they may think the room is twice as large as it really is. For that person, the mirror image is an illusion, they have been deceived about the nature of reality. If another person who knows the shop well walks in, then they also see the same mirror image, but they are not deceived by it, they may use it instead to check out parts of the room which they couldn’t see otherwise, they are using the mirror image as a tool like a car mirror. For the second person, the mirror image is not an illusion, it’s a useful tool for getting correct information about reality. Both of these people are getting the same sense-data from their visual systems, but whether those sense-data are an illusion or not depends on their interpretation. Or perhaps, more accurately, the second person is not dismissing the mirror image as a total illusion, they are correcting the illusory aspects of the image, while keeping the useful information.

I am saying that mirror images give us useful information about the world, but if we think they are direct representations of reality then they can become illusions. In the same sort of way, I think that the mirror systems in our brains which have evolved to give us information about other people’s thinking (by mirroring our own brain processes) are indeed useful, but they can become illusions if some misleading aspects of them are taken to be real.

Two aspects in particular (of the way we think about other people’s and our own thoughts) are misleading in that they are contradicted by the evidence from science: the idea that thoughts are essentially private to each individual, and the idea that we originate our own decisions. It’s these two aspects of qualia which are felt to be weird, anti-science. But I don’t think we need to accept those two aspects of qualia, in the same way that we don’t need to suppose that a room with a mirror for a back wall is twice as large as it really is, even though that is what it looks like.

I think there are good reasons why we have evolved to have those two misleading ideas, and why they can still feel persuasive.

1. The idea that thoughts are essentially private. Until very recently, we had no detailed information about the mechanistic brain processes which underlie our thinking, and even now brain scans are blunt instruments, without the resolution at the level of individual neurones firing many times per second which would be needed for useful prediction. The evolved mirror systems (unlike brain scans) are essentially guesswork, and while very useful, they are extremely vulnerable to our capacity for lying and concealing our thoughts, which we use all the time. It’s good to bear in mind that however convincingly I imagine what someone else is thinking, I could have got it entirely wrong (the basis of most novels). For practical purposes, our thoughts are still private to ourselves, so it is easy to be misled into thinking this is a feature of the ultimate reality of thoughts. If we think qualia are essentially private to each individual, then I would say we are making a mistake in the same way that someone thinking the mirror image is another half of the room is making a mistake. Science hasn’t got to the stage of reading thoughts in detail yet, but there’s nothing in principle to say that it won’t in future. (Of course, it may yet turn out differently, we can never be sure what will happen in an experiment, but the evidence so far suggests that thoughts are not inherently unreadable, they are merely mediated by exceedingly fast and complex processes.)

2. The idea that we originate our own thoughts and decisions. This includes qualia, if we suppose, for example, that one person could have a quale which is the same as most people’s yellow qualia, when they are looking at a red bus, and also that this would not show up as originating in their brain wiring. The scientific view is rather that any differences in qualia must (assuming the scientific model is correct) be caused by differences in the brain mechanisms. The unscientific misleading idea that we originate our own thinking runs into morality and the way human societies organise themselves, so it can feel actively dangerous to question it. Again, I think the correct response is that for practical purposes, because we don’t yet understand brain mechanisms in any detail, normal adults can be taken to originate their own decisions and actions (punishments and rewards are, so far, the best ways to influence them, not brain surgery), but that this is not an indication of ultimate reality.

In summary, I think that for most practical purposes in everyday life, when considering our thoughts and other people’s thoughts (including colour qualia), those mental events can be taken to be private to individuals, and originated by them, but that there is no need to suppose that the privacy or the origination, both of which contradict science, are aspects of ultimate reality. If they are treated instead as useful approximations (like Newtonian mechanics), they can be useful without being misleading illusions.