There’s Something About Mary

Frank Jackson on the Mary thought experiment and “Epiphenomenal Qualia”

Elsewhere I’ve written:

Jackson’s thought experiment bears a striking resemblance to Hayek’s discussion in The Sensory Order, 1.95. Hayek took inspiration from C. D. Broad, the idea that an omnipotent being would still not be able to predict the qualia associated with a substance, for example, ammonia (Broad, 1925, p. 71). Here Hayek poses the question: how could one communicate the idea of vision generally and color in particular to the congenitally blind? In The Sensory Order, 1.97 and 1.98, Hayek cites physicist Kenneth Mees’ thought experiment as illustrating the distinction between the physical and the phenomenal orders. Mees asks us to consider the case of a congenially and totally deaf person confronted by someone playing a violin. Moreover, he asks us to suppose that this person knows nothing of sound even in a theoretical way. Confronted by the actions of the violin player, to the deaf person the actions will appear irrational. But, says Mees, if our deaf person was a scientist, he or she would eventually figure out that the movements of the violin bow generated vibrations that could be detected by equipment (the science of acoustics). Now whatever the issues Hayek has with Mees’ example, his conclusion is this: ‘‘the congenitally blind or deaf can never learn all that which the seeing or hearing person owes to the direct experience of the sensory qualities in question, because no description can exhaust all the distinctions which are experienced’’ (Hayek, 1952/1976, 1.102). The similarity of the conclusion shared by Hayek and Jackson is uncanny.