Select two of the arguments against physicalism (Nagel’s bats vs Chalmers’s zombies, Nagel’s bats vs Jackson’s Mary / Fred cases, or Chalmers’s zombies vs. Jackson’s Mary / Fred case; Raffman’s argument on the persistence of phenomenology can also be one of the positions you discuss, if you want) and explain how both arguments are supposed to work. Make sure you identify at least one key difference in how these two arguments challenge physicalism. Then weigh up the two arguments, considering this difference. Which argument do you think is the strongest, and why?
Physicalism is the view that everything there is to the world can be explained in terms of the physical, as such that all physical facts exhaust all facts to the world. Qualia are qualitative experiences which are perceived by a person and appear contest the view of physicalism (Block, 1994). Sensations (colour, smell etc.) appear secondary to any quality of matter (mass, volume etc.). Physical objects cause the mind to experience conscious experience and also imposes how we sensationalise our experience with the physical world. Supervenience can be summarised as follows: “ x supervenes on y if and only if x changing requires that y also changes”. This can be derived to say that if y stays the same then there is no way x can change, but y can change without any change in x. For example, an essay supervenes on the ordering of the words; let us say you finish reading a copy of this essay and want something different to read, so you are given another essay and as you are reading it you realise it has the same words ordered in the same way as the first copy. Were you given a different essay to read? Regarding physicalism, supervenience states that the mind supervenes on the brain in such that any mental change requires there to be a physical change, e. g. antidepressants. However, it is believed that even with a different brain, or no brain at all, the same mental state can occur. Arguments against physicalism, such as David Chalmers zombie argument and Thomas Nagel’s bat argument, take into account qualia and independent experience to challenge physicalism.
In his article, Chalmers’ poses the question “ Is consciousness logically supervenient on the physical?” believing that if consciousness supervenes all, it must supervene locally rather than globally; that is all the microphysical facts of an organism entail all the facts about that organism.
In order to investigate this, he considers the possibility of philosophical zombies – an exact carbon copy of yourself, exhibits the same behaviour, same physiological functions and all, yet it does not experience any sensational phenomenon, i. e. there is nothing it is like to be a zombie. For example, Siri will respond to you cleverly but only because it is programmed to do so, we would not consider it conscious because it does not feel anything, nor does it have a sense of itself. Although the idea of a philosophical zombie seems impossible, as Chalmers says himself, “ intelligent behaviour and consciousness go hand in hand” (Chalmers, 1996), he is not arguing that zombies could exist, but that the fact that they are logically conceivable is enough to render the supervenience claim false. The simplest form of his argument is as follows (1) Zombies are conceivable; (2) Anything that is conceivable is possible; (3) Zombies are possible. Whether or not conceivability can be used as a guide to possibility needs to be considered. Zombies are not nomologically possible as they do not obey the laws of nature, however they are still logically possible as they are conceivable and that the “ burden of proof is on those who deny that they the possibility” (Chalmers, 1996). Take the essay example from before, if I print off two copies they are still the same essay, they still serve the same function of being read and marked. The situation is different in the case for consciousness. A molecule by molecule duplicate of a human does not guarantee it having conscious thought, and thus physicalism does not capture all there is to the world. Consciousness is more of an add on to the physical, meaning zombies could be possible, which contradicts the fact that they are not possible. Hence, supervenience fails.
Nagel asks in his article “ What is it Like to be a Bat” what it is like, for the subject of experience, to have an experience. Nagel chooses to use a bat as an example as he believes we can confidently say a bat experiences conscious thought, and that they are distinct enough from humans that we have no idea what it is like to experience conscious phenomenon as a bat. Nagel, however, explicitly states that the point he is trying to make with this metaphor is not an epistemological one (Nagel, 1974), i. e. he is not saying that we can not imagine what it means to behave as a bat, but rather we would need to see through the bats point of view to know what it is like to experience as a bat. Which leads to the question of how we can frame the problem of consciousness in order to obtain any sense of objectivity on the subject. He argues that that any attempts made to explain consciousness in an objective fashion would be undermined by the subjective nature of it. It is obvious that the more epistemic progress made to explain something, the more objective an explanation becomes. However, consciousness is a mental phenomenon that cannot be reduced to physicalism as the subjective point of view must be discarded. In this sense, it seems that detaching oneself from their own subjective way of looking at things to gather an objective explanation is counterintuitive as they are moving away from the very thing they want to investigate. Thus, it is impractical to consider any conscious experience as objective. Phenomenological sensation must be attributed to something physical if physicalism is to be defended, but as Nagel states “ every subjective phenomenon is essentially connected with a single point of view, and it seems inevitable that an objective, physicalist theory will abandon that point of view” (Nagel, 1974). Although, Nagel concludes his article in doubt as he calls it a mistake to claim physicalism as false, as the prospects for an objective science on the consciousness are limited.
Both Chalmers and Nagel go about attempting to refute physicalism in very different ways; Chalmers proposes a philosophical zombie with no consciousness and hence nothing it is like to be a zombie, whereas Nagel presents a creature with a consciousness to argue that we cannot know for sure what it is like to be that creature. In terms the strength of each philosopher’s argument refuting physicalism is, Chalmers’ zombie argument stands as a more reasonable than Nagel’s bat argument. Chalmers’ argument is not an uncontroversial one, meeting its share of criticisms and objections. For example, conceivability arguments are hampered by intellectual limitations (Chalmers, 1996), as Chalmers puts it, but conceivability is a stronger guide to explainability than it is to possibility; if zombies are conceivable, then no reductive explanation of consciousness is satisfactory. Consciousness escapes the net of reductive explanation, which further supports Chalmers’ claim that if zombies are conceivable then supervenience fails and therefore so does physicalism. Nagel’s argument on the other hand entirely depends on knowledge which is currently unobtainable. While he does firmly assert that a theory of physicalism will not hold up if an objective explanation of the consciousness were formed, he poses doubt by calling it a “ mistake” to disregard physicalism as a false theory. He says that it would be more reasonable to say that “ physicalism is a position on cannot understand because at present we do not have any conception of how it might be true” (Nagel, 1974). Nagel’s claim that a bat’s mind is inaccessible can also be criticised as that we can determine any important functions of a bat’s consciousness from our own perspective, as Dennett contends that it is clear a bat can only detect objects in the range their echolocation allows (Dennett, 1991). This suggests we can learn a lot about what it means to be a bat without actually being a bat.
Both philosophers, David Chalmers and Thomas Nagel present arguments against physicalism. Ultimately Chalmers’ zombie argument is the stronger out of the two as its problems only lie in its first premises, everything else follows logically; and even if conceivability is not as strong a guide to possibility, it is still a good guide to explainability. Nagel on the other hand presents his argument in doubt, not explicitly condemning physicalism, but rather being unsure of whether or not it can be true as current knowledge puts us at a disadvantage when trying to explain the consciousness objectively.
References
- Block, N. (1994). Qualia. In S. Guttenplan, A Companion to the Philosophy of the Mind (pp. 514-520). Oxford: Blackwell Publisher.
- Chalmers, D. (1996). Can Consciousness Be Reductively Explained? The Conscious Mind , 93-99 & 106-111.
- Churchland, P. (1996). The Hornswoggle Problem. Journal of Consciousness Studies , 402-408.
- Dennett, D. (1991). Consciousness Explained. Boston: Little, Brown and Co.
- Nagel, T. (1974). What is it Like to be a Bat. The Philosophical Review 83(4), 435-450.
