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Property Dualism (metaphysics of mind)

Terms in this set (21)

This thought experiment and its associated argument were created by Jackson to utilise the issue of explaining qualia through a purely physicalist explanation. (Refer back to the beginning of the guide for an explanation of qualia).

If reductive physicalism is true, then to know everything about something means to know all physical facts about it. For example to know all about an apple, I would need to know its size, genetic make-up, consistency, colour, taste etc. If there was any more to know about the apple, then it would be beyond physical knowledge and reductive physicalism would not be able to explain the world in its entirety.

Mary however, is raised in a black and white room so has never seen any colour. In this room, she comes to learn all physical facts about human biology, chemistry, the laws of physics and through all this - how we see colour. She doesn't just learn what we as a species learn now, but everything there is to know from the physical world.

Then, Mary is let out of the room and she sees colour for the first time. Jackson argues that when this occurs, she would learn something new - she would learn what it is like for others to see red. She experiences qualia of seeing red and with it, knowledge of what people experience when they see colour.

1. Mary knows all the physical facts about seeing colours before being released from her black and white room

2. On being released, she learns new facts about seeing colours

3. Therefore not all facts are physical facts

4. Physicalism claims that all facts are physical facts

5. Therefore, qualia are non-physical facts and physicalism is false
It is argued by some that you can know the same fact in different ways. For example, you can know that water hydrates us (fact about the world) but you can know this in different ways. You can know it in the sense that drinking water gets rid of thirst. But you can also know it in terms of H2O molecules and how they interact with the body. This is new knowledge but the same fact about the world (that water hydrates). This is sometimes explained in terms of concepts and properties - you know a fact about a property of the world but you can know more than one concept about that fact.

In this response, we can argue that Mary knows that red = certain light wavelengths. When she comes out, she does not learn a new fact about red, just a different way of knowing the same fact (red = phenomenal experience x). Therefore, we are accepting here that she does have new knowledge, but not about a new fact. She still knew all the facts within the room, even though she did not have all knowledge of different concepts about that fact.

Note: this is unlike the previous two critiques, as it is not arguing we do not gain new propositional knowledge; this critique accepts that we do gain new propositional knowledge.

Counter: Again, Jackson may respond to this saying with the new knowledge, comes a new fact about how others experience the world. She could not have known in the room the fact that red comes with a qualia experience of red. However opponents are likely to reject this as a 'fact' and say that she always knew they had colour related experiences.