Jackson F. (2010). " What Mary Didn’t Know". In J. Perry, M. Bratman, J.M. Fischer (Eds.), Introduction to Philosophy: Classical and Contemporary Readings, Fifth Edition, pp. 320-323. New York: Oxford University Press. (Original work published in 1986)
Jackson’s view implies a view of property dualism with respect to subjective consciousness as a whole = though the world contains only physical substances, some of the properties of physical substances are non-physical.
This relates closely to the idea of phenomenal properties (qualia) = properties of experience. Jackson suggests that qualia go beyond what can be described in purely physical terms. A commitment to qualia is called Epiphenomenalism = view that phenomenal properties are a kind of byproduct of physical causal processes that have no causal powers of their own.
The Knowledge Argument
Jackson talks about Mary’s thought experiment as the knowledge argument.
Summary of Mary’s though experiment = Mary is confined to a black-and-white room, is educated through black-and white books and through lectures on black-and-white television. In this way she learns everything there is to know about the physical nature of the world, for instance, learns all the physical facts about color, and is omniscient.
Does she learn something when she steps out into the real world? If yes, then physicalism is false. Physicalism tells us that everything in the world is physical stuff obeying physical laws, and there is nothing else. Our intuition says that Mary learns something when she leaves her black-and-white room and sees color for the first time. as she never knew what it looked like before. The new knowledge is not only knowledge about her own experience, but it’s also indirectly knowledge about other people’s experience. She comes to know what everybody else knows about the experience of color.
Jackson’s conclusion from this thought experiment is that since there is something that she came to learn, then physicalism offers an incomplete description of reality, leaving out the phenomenal aspects of consciousness.
Other views on the the thought experiment
It could be argued that while Mary does have a new kind of experience when she leaves the black-and-white room, the facts are the same physical facts she knew before leaving the room. David Lewis argues that physicalism remains true; Mary gains a new ability know-how to differentiate color, but she learns nothing new about color itself (know-that).
Another argument by Dennett is that Jackson’s thought experiment relies on intuition, and we don’t know how an omniscient being will think: are we in any real position to say what Mary would and wouldn’t know, given her omniscient physical knowledge. It can be argued that if her knowledge of the physical world is complete, she would not be surprised when she sees red for the first time as she would have been able to infer from her physical knowledge what the experience would be like. We can’t say anything on Mary’s situation as we are not omniscient.
Property dualism (Epiphenomenalism) and the Interaction-problem
Epiphenomenalism claims that there is one physical substance that has both physical and non-physical properties, avoiding the Interaction-problem of substance dualism. Given the Epiphenomenalist’s view that phenomenal properties don’t cause anything themselves, the traditional two-way interaction problem does not arise: qualia are not supposed to influence physical processes in the first place.
However, this gives rise to a different kind of interaction problem.
If phenomenal properties are by-products of physical processes, then physical events must somehow cause non-physical experiences. This raises the questions:
- How can something physical causally produce something non-physical?
- If qualia are causally inert, how can we know about them or talk about them?
- how can something with no causal influence play a role in our reasoning or behavior?
Other
Jackson also gives a thought experiment about difference in color vision. It is concerned with the fact that there is something about Fred’s experience, a property of it, not explained through physicalism. Even if we come to know about the property, no amount of knowledge, amounts to the knowledge “from inside” concerning Fred. There is this subjective nature of Fred’s experience, and a distinction made between first-person experience, and third-person observation, leading back into the problem with other minds.
He also puts forth modal arguments. Zombies = No amount of physical information about another logically entails that he or she is conscious or feels anything at. This not only talks about the possibility of zombies, but also applies to other human beings. It could be seen as a new form of the problem with other minds. A complete physical picture cannot tell us whether or not another human being is conscious. We inductively infer that people are conscious based on behavior, but behavior alone cannot logically entail consciousness. It’s the same sense that a philosophical zombie is physically and behaviorally identical to us, but doesn’t have consciousness.
Another modal argument is inverted qualia. A problem for physicalism and functionalism if it is possible on a metaphysical or physical ground. This is because it would mean that there are differences in mentality that aren’t fixed by the subvening realizing base, i.e. “there must be changes in the subvening base to change the supervening property.”
Assuming qualia evolved over time, we should expect qualia to be conductive to survival. Jackson refutes this on the observation that we should expect any evolved characteristic to be either conductive to survival or a by-product of one that is conductive (polar bear’s warm coat and its by-product of a heavy coat). In this case, qualia would fall into the latter category.
Jackson answers the importance of these epiphenomenal qualia by asserting that physicalism is an “optimistic view of our powers.” But we must admit that the probability that “everything in the universe is relevant in some way or other to the survival of homo sapiens” is surely low. It shouldn’t be surprising that there are matters that fall outside of our comprehension, and qualia is one of them.