Mary’s Room
Mary’s Room is Frank Jackson’s 1982 thought experiment, also known as the knowledge argument, against physicalism.
The setup
Mary is a brilliant scientist who has lived her entire life in a black-and-white room. She knows every physical fact about color vision: wavelengths, neural pathways, retinal chemistry, the lot. One day she walks out and sees a red tomato for the first time. Does she learn something new?
If she does learn something new, then there are facts about color experience (qualia) that aren’t captured by physical facts. So physicalism (the view that everything is physical) is false.
P1) Mary knew all physical facts about color before leaving the room.
P2) Upon seeing red, Mary learns something new (what red looks like).
∴
C) Not all facts are physical facts.
Why it's used in critical thinking
A clean example of:
- A deductively structured Argument
- A premise (P2) that seems obviously true but is actually contestable: physicalists deny that learning a new way of representing an old fact counts as learning a new fact
- How thought experiments isolate intuitions from confounders