I would like to explain how physicalism and materialism in general are undermined by Frank Jackson’s powerful Mary argument. Here is a summary of it:
Mary has lived in a black and white room all her life and acquires information about the world via black and white computers and televisions. In her room, Mary has access to all of the scientific objective information about what happens when humans see physical phenomena. She knows everything about the science related to perceiving objects with the human eye. Yet, she is unaware of what it is like to see colours. One day she is allowed to leave the room. The moment she opens the door she looks at a red rose, and experiences the colour red for the first time. She only appreciates the colour red the moment she sees it.[i] Her knowledge about all the physical facts concerning visual perception and colours did nothing to prepare her for the new experience of seeing red. She did not know what it was like to see a red rose by learning the physical facts, she only knew what that experience was like the moment it occurred.
Chalmers provides the following premises to show that the Mary argument renders materialism unable to solve the hard problem of consciousness:
- Mary knows all the physical facts.
- Mary does not know all the facts.
- The physical facts do not exhaust all the facts.[ii]
Chalmers’s argument here shows that knowledge of the physical world will not lead to knowledge of subjective conscious reality—for example, what it is like to see red. This seems to undermine materialism. Chalmers generalises the argument in the following way:
- There are truths about consciousness that are not deducible from physical truths.
- If there are truths about consciousness that are not deducible from physical truths, then materialism is false.
- Materialism is false.[iii]
Physicalism and materialism do not explain subjective consciousness because knowledge of the physical brain does not lead to an understanding of a subjective experience, and why that experience emerges from brain activity. Materialism is inadequate, because there are facts about consciousness that cannot be deduced from physical facts.
The Mary argument has generated interesting objections. One objection argues that it is not possible to identify what Mary would know if she acquired all of the physical facts. This objection misunderstands the Mary argument. It assumes that the Mary argument is focused on what it is like to know all the physical facts. However, the argument is focused on Mary’s inability to know what it is like to see red if she never had the experience of seeing red. Therefore, any objection to the Mary argument must focus on what Mary gains by seeing red and not what she would know if she had all the physical facts.
Another objection is the Ability Hypothesis. This hypothesis asserts that Mary does not gain any new knowledge, but only acquires new abilities. For example, when someone learns how to ride a bike they are not learning new things about the bike, they simply acquire the ability to ride it. This objection is considered inadequate. If Mary can gain new abilities when she leaves the room, then it is also possible that she gains new facts that she did not have prior to leaving the room. When someone learns how to ride a bike, they do not only acquire the ability to do so, they also gain new facts. For example, if someone is riding downhill fast, they will eventually learn not to constantly use the brakes as this will cause the rims to overheat. For a controlled descent, the brakes must be gently squeezed with around two second pulses.
Professor Brian Loar’s objection provides a strong challenge to the Mary argument. Loar argues that Mary does not acquire new knowledge about red, only a new way of conceptualising what she already knew about the colour. This strategy declares that there is only one property that can give rise to distinct concepts of that property. These concepts are physical-functional concepts and phenomenal concepts (concepts that refer to subjective experience). So, when Mary saw red for the first time, she was not experiencing a new property and learning new facts about it. She was experiencing a different way of conceptualising what she already knew. Prior to leaving the room, she recognised the property of red in physical-functional terms. However, when she left the room, she acquired a new way of recognising the physical property of red in phenomenal terms. Mary can only acquire phenomenal concepts when she sees red, because these concepts come about only by seeing the colour red.[iv] The main problem with Loar’s strategy is that it is based on the assumption that we can acquire phenomenal concepts from observing physical properties. However, this begs the question: How can our brains, while we experience the conscious state of observing a physical-functional property, acquire a phenomenal concept? Loar does not provide any adequate answer. The non-physicalist will then state that the Mary argument holds its ground because it provides an answer to that fundamental question: we gain phenomenal concepts because things (including ourselves) contain physical and phenomenal properties. In summary, to claim that phenomenal concepts can arise from a physical property is inadequate to explain the knowledge one gains from experiencing a subjective conscious experience.[v]
There are other reasons why Loar’s phenomenal concept strategy is not decisive. For detailed discussions and responses to Loar’s account, please refer to Michael Tye’s Consciousness Revisited: Materialism Without Phenomenal Concepts[vi], Erhan Demircioglu’s Physicalism and Phenomenal Concepts[vii], Karol Polcyn’s Brian Loar on Physicalism and Phenomenal Concepts[viii] and David Chalmers’s essay, Phenomenal Concepts and the Explanatory Gap[ix]. The academic literature on the Mary argument is also vast, with compelling arguments supporting and challenging physicalism. This is not the space to explore the literature on the topic. However, the academic discussions do not conclusively undermine what has been presented in this section.
[i] Jackson, F. (1986). What Mary Didn’t Know. The Journal of Philosophy, 83, 5, pp. 291-295.
[ii] Chalmers, D. (2010). The Character of Consciousness, p. 108.
[iii] Ibid, p. 109.
[iv] Loar, Brian. (1997). “Phenomenal Consciousness”, in The Nature of Consciousness: Philosophical Debates. ed. by Ned Block et al. Cambridge, Massachusetts: MIT Press.
[v] The above discussion has been taken and adapted from the relevant lecture and seminar discussion that was held during my postgraduate degree (Masters in Philosophy). Patterson, S. (2016). Week 6: Responses to the Modal and Knowledge Arguments. Lecture notes distributed in Philosophy of Mind at Birkbeck College, University of London on 16th November 2016.
[vi] Tye, Michael. (2009). Consciousness Revisited: Materialism without Phenomenal Concepts. Cambridge, Massachusetts: MIT Press, pp. 49-51.
[vii] Demircioglu, Erhan. (2013). “Physicalism and Phenomenal Concepts.” Philosophical Studies: An International Journal for Philosophy in the Analytic Tradition, 165, 1.
[viii] Polcyn, Karol. (2007) “Brian Loar on Physicalism and Phenomenal Concepts.” Diametros, 11, pp. 10-39.
[ix] Chalmers, D. (2007). Phenomenal Consciousness and the Explanatory Gap. In: Alter, T. and Walter, S. (ed). Phenomenal Concepts and Phenomenal Knowledge: New Essays on Consciousness and Physicalism. New York: Oxford University Press. A version of this essay can be found online at: http://consc.net/papers/pceg.pdf [Accessed 21st November 2016].