Today’s LiveJournal interest explained: Qualia.
Qualia is the experience of something. Look at this:
You are seeing red in front of you. You are having an experience of redness. What does that mean, exactly? Is this the same experience other people have when they look at it? Why can’t you describe the experience of redness? That is qualia. Qualia is a very slippery thing, but it exists. It is a product that exists entirely within the conscious mind, but it is a product with real properties.
The classic thought experiment is as follows:
Mary was born and raised in a black and white room. All her books are black and white, her clothes are black and white, her skin is black and white (because of magic light bulbs), and her only view of the outside world is through a black and white TV. However, Mary is a brilliant woman, and a scientist. Not just any scientist, mind you, but a scientist who studies colour. She knows everything there is to know about the physics of colour, she’s interviewed countless people over the phone about their subjective experiences with colour, she knows what neurons talk to other neurons when people are exposed to colour, she knows what colours are complimentary and what colours clash — she’s just never seen colour.
But when we bring a red apple into the room, Mary will say ‘holy fuck’. We’ve taught Mary something. We’ve taught her the experience of redness.
If Mary knew everything there was to know about the physical properties of colour, but she still learned something new when we gave her an apple, then what she learned cannot be described or explained through physical means. Which means that physicalism (the belief that all things which exist have physical properties) is clearly wrong, and a non-physical property (the qualia of redness) caused a physical reaction (Holy fuck!)
Consider: If we had painted the apple blue before we give it to her, is it possible she would have said “You tried to fool me, this is blue”?
Qualia fucks me up.