Name: How Do We Perceive Color?
Uploaded: 2015-06-09T08:33:16.000Z
Duration: 4 min 6 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

You know a funny thing about the contemporary

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neuroscience of consciousness is it's really closet philosophy. It's really it's

very often making fundamental philosophical assumptions. That is to say it\\'92s taking

certain philosophical ideas for granted and it\\'92s often using empirical information

simply to reanimate old debates. For example, one of the basic sort of guiding pictures

I think that people thinking about the neuroscience of consciousness have is that the world is

in our head The brain makes the world, that is what we experience is not\\'97I don\\'92t

experience you. I don\\'92t see you. I experience something in my brain that is confabulated

on the basis of a pattern of stimulation.\\ Let me come to the nature of color as an example

to try to illustrate what I have in mind. And by the way this is a wonderful area where

both science and philosophy have tended to really collaborate, have been in dialogue

with each other and in many cases the leading philosophers have also been the leading scientists

thinking about this. One view is that color is a property of the surfaces of objects,

not the property we naively think we see, but maybe something like a disposition to

absorb and reflect light of certain wavelengths and to produce a sort of what is known as

a spectral reflectance profile, but the color is on the surface. Another view is that it\\'92s

an illusion to think of color as something in the thing, that color is merely an affect

that the thing has on us. In that sense the color happens to us. The leaves in the tree

are not green. Greenness is just something that happens. In me it\\'92s a kind of sensation

that is produced thanks to the activation of my nervous system by those leaves.\\

My own view is that both of those views are wrong. I advocate the view that color is what

you might call an ecological property and by that I mean color is a feature of the way

light and surfaces interact. It\\'92s not in that sense intrinsic to the surface of the

leaf that it is green. Its greenness is the way it behaves in relation to lighting. So

we think of the color as stable, but of course the color looks one way under one light and

if you take it outside it looks different and if you turn it in certain ways there will

be highlights and sort of little specular shining points on the surfaces of things that

are all part of the real color of the thing. For me colors are like shapes. Just as a three-dimensional

shape has a hidden backside so colors have hidden ways they would look if the conditions

of lighting were changed.\\ The problem of skepticism about the external

world, how do we know that things are the way they seem to be, how do we know that our

perceptual experiences are reliable is a chestnut. It\\'92s an old philosophical chestnut that

I can\\'92t solve for you right now and that neuroscience can\\'92t solve, but what I\\'92d

like to impress on you is that neuroscience has taken a solution to that or at least an

attitude towards that old philosophical chestnut for granted and most neuroscientists working

on consciousness suppose experience is something that happens inside of me. It\\'92s subjective.

It\\'92s hidden. The world is this we know not what which is beyond the surfaces of our

tent. Beyond the reach of our direct knowledge because all we ever know is the way our nervous

system is bombarded by stimulation, that which is causing the stimulation is always beyond