First published: January 21, 2025
Last revised: April 16, 2025

Rather than asking whether Mary obtains new knowledge upon seeing color for the first time, we could ask what she can do after seeing it, that she could not do before. This goes straight to something measurable.

One thing that comes to mind is that a qualia gives her knowledge of the internal state of some part of her own brain. And this privileged access to qualia again brings me back to Maxwell's demon who knows the microscopic state of the gas in the chamber, even if this state is unknowable from the outside.

So what does it mean for her to "know" the state? Perhaps it means that some degrees of freedom in the brain (the ones responsible for the self-knowledge) are tracking the degrees of freedom that are responsible for instantiating the qualia.

Does this type of self-knowledge / self-reference lead to a measurable difference?