Abstract
One reason for the recent attention to conceivability claims is to be found in the extended use of conceivability in philosophy of mind, and then especially in connection with zombie thought experiments. The idea is that zombies are conceivable; beings that look like us and behave like us in all ways, but for which “all is dark inside;” that is, for a zombie, there is no “what it is like.” There is no “what it is like” to be a zombie, there is no “what it is like” for a zombie to feel pain, there is no “what it is like” for a zombie to taste, or feel, or smell something. They are creatures without consciousness. I am skeptical about the conceivability of zombies. That is not to say that I believe that there is some inherent contradiction to be found in the idea of zombies. Instead, I do not think that I am justified in believing that zombies are conceivable. The focus on justification is not common in the literature on conceivability, or for that matter in the literature on the possibility of zombies. Instead, the focus tends to be on trying to find out whether or not the notion of a zombie is contradictory. It is widely accepted in the literature on conceivability that the absence of a contradiction when conceiving of X is both necessary and sufficient for X to be conceivable. That might be true of ideal conceivability, but as I will argue below, ideal conceivability is not relevant to our (human) pursuit of knowledge and understanding. Further, as I will argue, once we focus on non-ideal conceivability the notion of justification, and degrees of justification comes into play.
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Notes
van Inwagen has argued that when conceiving of a situation or scenario one needs to consider all the detail. For example, if conceiving of purple cows then one needs to think about how the relevant pigment can be placed in the cows DNA. This requirement, as I have argued elsewhere, is excessive. For more on van Inwagen’s argument, see van Inwagen (1998).
Kripke (1977).
"Does Conceivability Entail Possibility?," 160.
Putnam (1975).
Chalmers, The Conscious Mind: In Search of a Fundamental Theory: 57.
I discuss the general issue of conceivability in more detail in Geirsson (2005).
Kripke (1980) 34–35.
Casullo discusses some of these issues on pp. 57–58 in Casullo (2003).
It is, in addition to general considerations of our use of an ideal reasoner, debatable what exactly an ideal reasoner knows when it comes to conceptual knowledge, which is the kind of knowledge Chalmers requires for his ideal reasoner. For a discussion on whether conceptual knowledge is adequate for the job at hand for the ideal reasoner see Block and Stalnaker (1999), as well as Polger (Polger 2008).
Chalmers, The Conscious Mind: In Search of a Fundamental Theory: 95.
Ibid., 96. We should read Chalmers’s “logical possibility” here as “coherent conceivability.”.
Ibid., 99.
The example is Seddon’s. See Seddon (1972).
The first possibility is represented by Type-A materialists who claim that zombies are not conceivable. On the other side we have Type-B materialists who agree with Chalmers’s premise that zombies are conceivable, but then disagree that it follows that zombies are metaphysically possible. I do not want to get embroiled in the issue of which type of materialism is correct, or even whether materialism is correct.
The position I take undermines Chalmers’ conceivability claim without having to make either of the strong claims of the Type-A and Type-B materialists, namely that either one cannot conceive of zombies or that conceivability does not entail possibility.
While there are different accounts of conceivability, the one that is relevant here is not explanatory coherence but rather whether we can, objectively, describe a zombie world. For an account of some of the requirements for an objective coherence see BonJour (1985) 95–98.
There are other factors as well that go into the evaluation of coherence, factors that we need not take into account. For example, a comprehensive evaluation of coherence would include assigning a weight to the various factors that play a role in coherence; something that is hard to do in even the simplest of cases.
The dialogue plays, of course, on what Chalmers calls “the paradox of phenomenal judgment.” Chalmers thinks that the paradox is “delightful and disturbing” while “not obviously fatal to the nonreductive position.” Chalmers, The Conscious Mind: In Search of a Fundamental Theory: 181. Chalmers’s optimism, I believe, results from a very lax take on what is involved in coherence.
I am assuming throughout the paper that zombies can have beliefs. Chalmers assumes so as well, although he claims that it is by no means obvious that it is so, thus further reducing the clarity of the conceivability claim. See Chalmers (2006).
Katrin Balog considers the possibility of ‘pain’ referring in a zombie world and uses that assumption to provide her “zombie refutation”; namely, she argues that physicalism is false in the zombie world is given that ‘pain’ refers. See Balog (1999).
There are of course various explanations as to why zombies might not be conceivable. One such focuses on the difference between a first-person imaging and third-person imaging, arguing that there is a difference between imaging a creature that lacks consciousness, and imagine a creature that may or may not have consciousness without also imaging consciousness it may possess. See for example Marcus (2004).
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I thank referees of the journal for helpful comments.
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Geirsson, H. Conceivability and Coherence: A Skeptical View of Zombies. Erkenn 79, 211–225 (2014). https://doi.org/10.1007/s10670-013-9486-8
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DOI: https://doi.org/10.1007/s10670-013-9486-8