There are a lot of famous Marys. There's Mary the Mother of Jesus, Mary Poppins, Mary Queen of Scots, Mary from There's Something About Mary, in the UK where I'm from there's Mary Berry, Mary Who Had a Little Lamb and Mary Who Was Quite Contrary. In this video I'm going to tell you about another Mary who's famous in philosophical circles. This is because of the work of Frank Jackson and a thought experiment he came up with called Mary's Room which has given rise to an argument.
known as the knowledge argument. The knowledge argument is an argument that's supposed to show that physicalism or materialism about mental phenomena is false. Let me just quickly say that whilst physicalism and materialism are sometimes distinguished as slightly different positions, I'm going to think about them in the same way for the purpose of this video and from now on I'll just speak about physicalism.
What then is physicalism about mental phenomena? It's actually surprisingly difficult to say, as it's pretty hard to define what we mean by physical. For our purposes we'll just understand it as the view that there's nothing immaterial about our mental lives, and that they're all just made up of physical or material stuff.
So if you hear someone say your thoughts, feelings etc. are just firings in the brain and there's nothing more to them than that, then you're very likely speaking to a physicalist. So why does the knowledge argument suggest that physicalism is false? To see why I'm going to need to tell you some more about Mary.
Mary, for one reason or another, has always lived in a black and white room. Yet despite this, Mary is a brilliant scientist. Actually, she's the world expert on the colour red. In fact, Mary is so knowledgeable about red that she knows all the physical facts there are to know about red. And as she exists in the future, where all the physical facts about red have been discovered, she doesn't lack any of them.
She knows its wavelength, what happens in our brain when we see red, etc. But there's one strange fact about Mary that I'm yet to tell you. And this is that Mary has never actually seen a red object. Now imagine that someone gives Mary a red object for the first time. Let's say a red mug.
The question to ask yourself is this. When Mary gets this red mug and sees red for the first time, does she learn something new? Many philosophers think that it's obvious that she does. She learns what it's like to experience red, what is often called the phenomenal nature of red or red qualia.
But if Mary knew all the physical facts about red to begin with, she must now be learning some non-physical facts about red, since if the fact was physical, she'd have already known it. So because Mary gains an item of knowledge, we must conclude that physicalism about the mental is false, since there are some non-physical aspects about it as well. We can also run versions of this argument that don't involve visual perception.
For instance, we can ask the same story about someone who is deaf. Again this time we have an expert scientist who knows all the physical facts there are to know about hearing but they don't know what it's like to hear. Now suppose due to some medical intervention the scientist does come to hear. The question again will be whether they learn something new and if in fact they do then this will be a non-physical fact.
Interestingly, due to scientific advancements there are actually many videos online where people do come to hear for the first time. due to medical interventions, and it seems, having watched some of them, that they do come to learn something new, namely what it's like to hear. Admittedly, these people aren't world experts in hearing, and so do not know all the physical facts about it.
But do you think that if they did know all the physical facts, that they wouldn't come to learn something new when they heard sound for the first time? What then do you think of this argument? Is it successful in showing that physicalism about the mental is false, or do you think there are problems with it? and ways that physicalists could reply.
Let's briefly look at four different types of reply that physicalists have offered. The first kind of reply relies on there being different types of knowledge. Here's an example of this approach.
You know how to use your phone, but if I said to you write down exactly how your phone works, it's unlikely that you would be able to. This latter type of knowledge we call propositional knowledge, knowledge of truths or information. Whereas the former type of knowledge we'll call know-how, which is to do with possessing certain abilities.
With this distinction, what physicalists claim is that Mary, when she sees a red object for the first time, just acquires new abilities rather than learning new truths. She gains know-how rather than propositional knowledge, which is sometimes called knowledge that. This type of reply is often known as the ability hypothesis. and claims the thought experiment fails since it requires that Mary learns new propositional truths.
But those offering this reply say that she doesn't, she just acquires new abilities, like the ability to imagine, remember and recognise red colours. The second type of reply says that what actually happens in Mary's case is that she just learns an old fact in disguise. She doesn't actually learn anything genuinely new.
We'll call this the new knowledge old fact reply. The key thought here is that although Mary seems to gain new knowledge, in reality she just apprehends old and previously known facts, but in a new way. Here's an example. Suppose Lois Lane, knows that Clark Kent is 35 years old, but she doesn't know that he's Superman. Now suppose she finds out that Superman is also 35 years old.
Lois might think she's learned a new fact, namely how old Superman is, but she hasn't really, since how old Clark is and how old Superman is are one and the same. One way to describe what happens to Lois is that she comes to apprehend a fact she already knew, but in a new way. Similarly, What happens to Mary when she sees a red object for the first time is that she just comes to know facts she already knew but in a new way, and in a way in which was unavailable to her while she was in the black and white room. She comes to represent those facts she already knew under new concepts, or different guises, or alternative modes, or can represent them in a different way. The exact details of this type of reply vary, but what I've told you gives you the overall gist of what they say.
Here's a third type of reply that physicalists give. This time they claim Mary doesn't learn something new when she sees a red object for the first time, and we're mistaken if we think she does. If we think she does, we're just really underestimating what knowledge of all the physical facts would be like.
It's far more comprehensive than we think. The fourth type of reply is different, and this says that if Mary was in a black and white room then she couldn't know all the physical facts there are to know about red. She might have the best teacher in the world, obviously me, but there are limits as to what even I can teach her in a black and white setting. Because of this, Mary cannot know all the physical facts about Red, and so the thought experiment fails.
Let me briefly say something in response to this that you might find interesting. Knut Nordaby was pretty much a real-life version of Mary. He was an expert in the science of colour vision, but was himself colourblind. Maybe this gives us some reason to think that even in a black and white room, Mary could know all the physical facts there are to know about red. Anyway, as you can imagine, these replies to the knowledge argument have gained further replies from those who think the knowledge argument succeeds.
But what do you think of them? Are they plausible? And if you had to, how might you respond to each of them?
There are many other arguments people have given for thinking that physicalism about the mental is false. and in future videos I'll tell you about some more of them so if you don't want to miss out on that then please subscribe and if you found this video helpful then give it a like.