I just read a blog-post taking up the story of Red Mary, a philosophical thought-experiment. Mary is a neuroscientist who has never seen colours, but has studied them scientifically. For the sake of the argument Mary is taken to have learnt everything that can be learnt about colours, without ever seeing them. The question philosophers now debate is whether Mary learns anything new when she is released from her monochrome prison and sees colour for the first time.
Intuitively, we agree Mary “learns” something new, namely “what it’s like” to see red etc. A similar conundrum “What is it like to be a bat” discusses the fact that we may know much about bats, but not what it’s like to be one. Both are intended to prove dualism, or the idea that there is something non-phyiscal in the world, the carrier of the so-called qualia – from qualis est or lat. what / how is it, or “how-ness”.
Reading these things feels a bit like watching a dog trying to catch its own tail. Of course, dogs eventually learn the trick of leaning against something…
Seeing is a skill
To make it easier, suppose Mary’s new experience is not seeing colour, but riding a bike, where she has no previous experience with anything wobbly on wheels. It’s fairly obvious that the outcome would simply be that she cannot ride a bike.
I would argue it’s the same with seeing colour. After a lifetime in monochrome Mary’s eyes might “see” the colours, i.e. the photo-sensitive cells might still be there, and they might react to the photons, but her visual apparatus would simply not have developed a reaction to it. Neurons that have never fired will not be connected to the visual cortex: she will not visualise or experience red at all.
We are not passive spectators of our experience; consciousness is a process, a skill that has to be learnt, just like riding a bike. We start with something quite basic and build it up as we develop. If we never use it, particularly in childhood, it atrophies and disappears.
This in itself is a fantastic quality of our brain. This is how we each develop an ear to detect and differentiate the sounds characteristic of our own language – how marvelous is that? And this is why our eyes are attracted to writing, as we’ve learnt this carries meaning, yet we ignore scratches on the pavement. In former times we’d have learnt to watch out for traces of sabre-toothed tigers…
Mental filing cabinet
An independent point is that seeing colour is a physical sensation. Neurons carry impulses to the part in my brain that maps information onto a body outline, to tell me what’s going on where. Knowing something theoretical, like “my phone number is 431234” is also an electrical impulse in my brain, but it’s in a completely different circuit. Everything I learn by reading, say, is put into the top mental drawer, body information is in the bottom one. This is brain-hardware.
No piece of information Mary can learn about colour is the same as “seeing” it in her visual cortex. Nothing you put in the top drawer is then in the bottom one. On a smaller scale there is no colour seeing which is “like” having a toothache (though some modern artists do try), and no smell is “like” a butterfly kiss. And no piece of information I learn about your height will make me believe you are a good cook (this one is brain software: I could, illogically, have learnt that the best cooks are 5’7” and vice versa).
That doesn’t mean we need to multiply metaphysical entities as carriers of the how-ness of smells, of colours, of touch etc. Not to mention of height and of being a good cook. If we have separate drawers in our mental filing cabinet, that is a quality of our brains, and it doesn’t imply that there is a top-drawer world separate from a bottom-drawer one, any more than the world we hear must be separate from the world we see.
Similarly, the reason I can’t know what it’s like to be a bat is simply that I don’t have a bat’s body. My body-feeling brain circuits are not built the way a bat’s are, nor are my cognitive processes.
What I find telling, is that in trying to prove the existence of “more than” the physical world, the dualist philosophers manage to ignore so much about the physical world. In particular the physical, very much awe-and-wonder-inspiring bodies we are so lucky to have.
P.S. Bats and colours
Bats obviously don’t see colours (different wavelengths of light) as they “see” by ultrasound echoes, i.e. sound waves. Biologist Richard Dawkins once speculated that bats might use what in our brains is used to visualise colours, to represent different textures of surfaces. I find this idea totally fascinating: would blue be smooth, and red be rough?