Online research in philosophy

A philosophical zombie is a being indistinguishable from an ordinary human in every observable respect, but lacking subjective consciousness. Zombiehood implies *linguistic indiscriminability*, the zombie tendency to talk and even do philosophy of mind in language indiscriminable from ordinary discourse. Zombies thus speak *Zombish*, indistinguishable from English but radically distinct in reference for mental terms. The fate of zombies ultimately depends on whether Zombish can be consistently interpreted. If it can be interpreted consistently, then zombies remain possible, but no test could ever reveal whether anyone (oneself included) is speaking Zombish. Any materialist theory of consciousness is therefore already a theory in Zombish, and is equally confirmable in its human language edition (applicable to humans) and its zombie-language edition (applicable to zombies). On the other hand, if Zombish cannot be consistently interpreted, then the zombies described in Zombish are logically impossible. Either way, the search for a materialistic theory of consciousness should be untroubled by the (possible) zombies among us.

Zombies are hypothetical creatures of the sort that philosophers have been known to cherish. A zombie is physically identical to a normal human being, but completely lacks conscious experience. Zombies look and behave like the conscious beings that we know and love, but "all is dark inside." There is nothing it is like to be a zombie.

A zombie is a creature just like a conscious being in certain respects, but wholly lacking in consciousness. In this paper, I look at zombies from the perspective of basic ontology (“from below”), taking as my starting point a trope ontology I have defended elsewhere. The consequences of this ontology for zombies are mixed. Viewed from below, one sort of zombie—the exact dispositional zombie—is impossible. A similar argument can be wielded against another sort—the exact physical zombie—but here supplementary principles are needed to get to the impossibility result. Finally, at least two sorts of zombie—the behavioural and functional zombies—escape these arguments from below.

Zombies, as conceived by philosophers these days, are supposed to be creatures that are physically indistinguishable from normal people that nevertheless completely lack phenomenal consciousness. The kind of zombie I want to focus on is one that is molecule- by-molecule identical to a healthy, normal, adult human being living in a world physically like ours — indeed this might be our own actual world. To make things more concrete, pick any such person that you actually know. Let this be John. John is not a zombie. Now consider an exact, perfect, physical replica of John, call him Zhon. Note that because John and Zhon are physically alike, they are also behaviorally and functionally alike. So if you were to encounter Zhon, you could not distinguish him from John. Under the imagined circumstances so far, you would normally expect Zhon to be conscious as well. But let’s stipulate that Zhon has no conscious experiences whatsoever — he’s never had them, nor will he ever have them. So Zhon, according to this stipulation, doesn’t know — indeed cannot know — what it is like to have conscious experiences of any kind. There is nothing it is like to be Zhon. Zhon lacks conscious phenomenology altogether. If Zhon were to be a metaphysically possible creature, he would be a zombie.1 So this is the notion of zombie I would like to focus on. According to many philosophers, Zhon is a possible creature, and that is because Zhon is a conceivable creature. This gives us the argument from zombies against physicalism. Physicalism is the doctrine that says: all that exist is physical through and through, including conscious minds and their conscious experiences. The zombie argument, as we might call it, is a species of conceivability arguments: 1. If Zhon is conceivable, then Zhon is possible. 2. Zhon is conceivable. 3. Hence, Zhon is possible. Now since the choice of Zhon was arbitrary, we can, of course, generalize the argument to all zombies like Zhon — that is, to zombies that are physically indistinguishable, in relevant respects, to healthy, normal, adult human beings..

A prevailing view in contemporary philosophy of mind is that zombies are logically possible. I argue, via a thought experiment, that if this prevailing view is correct, then I could be transformed into a zombie. If I could be transformed into a zombie, then surprisingly, I am not certain that I am conscious. Regrettably, this is not just an idiosyncratic fact about my psychology; I think you are in the same position. This means that we must revise or replace some important positions in the philosophy of mind. We could embrace radical skepticism about our own consciousness, or maintain the complete and total infallibility of our beliefs about our own phenomenal experiences. I argue that we should actually reject the logical possibility of zombies.

Todd Moody’s Zombie Earth thought experiment is an attempt to show that ‘conscious inessentialism’ is false or in need of qualification. We defend conscious inessentialism against his criticisms, and argue that zombie thought experiments highlight the need to explain why consciousness evolved and what function(s) it serves. This is the hardest problem in consciousness studies.

Zombies and minimal physicalism -- The case for zombies -- Zapping the zombie idea -- What has to be done -- Deciders -- Decision, control, and integration -- De-sophisticating the framework -- Direct activity -- Gap? What gap? -- Survival of the fittest.

According to the zombie conceivability argument, phenomenal zombies are conceivable, and hence possible, and hence physicalism is false. Critics of the conceivability argument have responded by denying either that zombies are conceivable or that they are possible. Much of the controversy hinges on how to establish and understand what is conceivable, what is possible, and the link between the two—matters that are at least as obscure and controversial as whether consciousness is physical. Because of this, the debate over physicalism is unlikely to be resolved by thinking about zombies—or at least, zombies as discussed by philosophers to date.



In this paper, I explore an alternative strategy against the zombie conceivability argument. I accept the possibility of zombies and ask whether that possibility is accessible (in the sense of ‘accessible’ used in possible world semantics) to our world. It turns out that the question of whether zombie worlds are accessible to our world is equivalent to the question of whether physicalism is true. By assuming that zombie worlds are accessible to our world, supporters of the zombie conceivability argument beg the question against physicalists. I will then consider what happens if a supporter of the zombie conceivability argument should insist that zombie worlds are accessible to our world. I will argue that the same ingredients used in the zombie conceivability argument—whatever they might be—can be used to construct an argument to the opposite conclusion. If that is correct, we reach a stalemate between physicalism and property dualism: while the possibility of some zombies entails property dualism, the possibility of other creatures entails physicalism. Since these two possibilities are inconsistent, one of them is not genuine. To resolve this stalemate, we need more than thought experiments.

Many philosophers accept the conceivability of zombies: creatures that lack consciousness but are physically and functionally identical to conscious human beings. Many also believe that the conceivability of zombies supports their metaphysical possibility. And most agree that if zombies are metaphysically possible, then physicalism is false. So, the claim that zombies are conceivable may have considerable significance.¹.