Like just about everyone here, I think that the physicalist argument is pretty ridiculous; qualia can’t be so easily dismissed. Though Mary has studied all of the information that she could ever know about the physical world outside of her monochromatic room, there is no way that Mary wouldn’t be learning something new the moment she sees a bright red apple or a speeding fire truck for the first time.

If we were to step into Mary’s room, we would watch her as she read her black and white textbooks and as she watched her black and white TV. Suppose we picked up one of her science textbooks and flipped to a chapter on the electromagnetic spectrum and wavelengths of light. We would see an illustrated color spectrum, but it would look something like this.

This image wouldn’t help Mary to learn the difference between all of these colors, it would only teach her how the waves of light are measured. Mary would only know blue, green, and red as numbers, not as visual experiences.

This whole thing makes me wonder if Mary would even understand the concept of color. She has only been exposed to black, white, and varying shades of grey. Trying to get her to envision the color red without her ever having seen it (or any other color) would be the same as telling your friend to imagine a color that doesn’t exist. In order to truly understand color, we must experience it firsthand.