Do we see colour the same?
How do you know something? What if you think something is true – but actually you’re just imagining it?
Professor Bill Child of the Faculty of Philosophy at the University of Oxford has been thinking about these questions for years – before he even knew what Philosophy was.
“I remember talking to friends at school about whether it’s possible for anyone to do anything that isn’t, in the end, self-interested,” he recalls. “Sure, people do things that seem not to be self-interested – they give to charity, or they take a cup of tea to a lonely neighbour, or they walk someone’s dog. Then there’s the counterargument - well, really the reason for walking the neighbour’s dog is that you want to make yourself feel good, or if you didn’t do it you’d feel guilty. Or you’d be tortured by thoughts about your elderly neighbour and the dog whining as it hadn’t been walked. So when you think about it, it’s not unselfish - you’re just avoiding your own feelings of discomfort.”
At university, he found out that these kinds of debates are what Philosophy is all about. One of the most intriguing questions is whether a colour is actually real.
Sound ridiculous? Well, let’s dig a bit deeper about this...
Mary’s Room
There’s a famous thought experiment called Mary's Room – where Mary is a brilliant scientist who is investigating the world from a black and white room via a black and white television monitor. She knows all about vision, and how the eye sees colour, and how the brain names what it sees. Essentially, she knows all about the science of colour – but she has never experienced colour herself. When she experiences colour for the first time, does she learn anything new or not?
Most people think Mary does learn something new. There was something she didn’t know when she was in the room – which is what it’s actually like, seeing coloured things. Now she’s seen some coloured things, she knows what seeing colour is like.
Why’s that important? “Well, people will say, ‘Look – when Mary came out of the room, she learned a new fact’” Professor Child explains. “But she knew all the physical facts already. So there are some facts about the world that aren’t physical facts. Mary’s Room proves that there’s more to the world than physical reality.”
And Mary’s Room raises another question. Is the way things seem to us the same as the way they really are?
Professor Child says that our own experiences shape what we think when we see something or someone for the first time.
“There are all sorts of properties that we think we can detect on the basis of our perceptual experiences – the shapes of things, their sizes, their colours,” he says.
You might look at someone and think that you know that they’re French – but how can you see ‘Frenchness’? You can’t.
“Frenchness isn’t itself a perceptible property, but if you can see that someone is French by looking at them, it’s because of the clothes they’re wearing, or their hairstyle,” he says. “You’re perceiving other properties, and detecting the property of being French on the basis of that.”