Welcome to the end of summer, thought-experiments bash! For the month of August we will be exploring classic thought-experiments from science and philosophy! So put on your thinking caps. It’s Gedankenexperiment August!
What Mary Knows:
Philosopher Frank Jackson first conceived this thought-experiment in order to explore some of the strange difficulties in constructing a science of consciousness. Assume a flat ontology—the universe is material and only material processes occur. Mary is a future neurobiologist. She knows everything there is to know about the brain’s processing the color red. Everything. From the time the light photons enter the eye and activate nerves in the retina, to the time it is processed in the visual cortex and on until that information is processed, distributed, and used by the rest of the brain.
Mary knows everything about seeing red—except Mary is colorblind. She has never seen red. Jackson then asks what happens when her abilities are restored through some surgical manipulation. Does Mary learn something? Upon seeing red does she say, “Ah yes, just as I expected.” Or does she say, “Wow. I had no idea?” She knew everything science could possibly find out about seeing red, yet there appears to be something she did not know. The implication is that there are at least some things that science cannot reach—in particular the nature of the ‘experience’ of subjectivity.
This thought experiment has generated much spilled ink in the consciousness literature. It also seems to offer something about the nature of science and its ability to get at some questions.