Online research in philosophy

Philosophical (p-) zombies are constructs that possess all of the behavioral features and responses of a sentient human being, yet are not conscious. P-zombies are intimately linked to the hard problem of consciousness and have been invoked as arguments against physicalist approaches. But what if we were to invert the characteristics of p-zombies? Such an inverse (i-) zombie would possess all of the behavioral features and responses of an insensate being yet would nonetheless be conscious. While p-zombies are logically possible but naturally improbable, an approximation of i-zombies actually exists: individuals experiencing what is referred to as “anesthesia awareness.” Patients under general anesthesia may be intubated (preventing speech), paralyzed (preventing movement), and narcotized (minimizing response to nociceptive stimuli). Thus, they appear—and typically are—unconscious. In 1-2 cases/1000, however, patients may be aware of intraoperative events, sometimes without any objective indices. Furthermore, a much higher percentage of patients (22% in a recent study) may have the subjective experience of dreaming during general anesthesia. P-zombies confront us with the hard problem of consciousness—how do we explain the presence of qualia? I-zombies present a more practical problem—how do we detect the presence of qualia? The current investigation compares p-zombies to i-zombies and explores the “hard problem” of unconsciousness with a focus on anesthesia awareness.

We imagine Zombies as beings identical to us with respect to all physical and behavioural facts but different with respect to phenomenal facts. For example, zombies might say, just like us, ‘this grapefruit is really sour’ or ‘my left knee hurts’, but, unlike us, they have no phenomenal experiences corresponding to these utterances or to the relevant physical states. The idea of zombies has been used to construct the following argument against the physicalist approach to consciousness.

Zombies are bodies without minds: creatures that are physically identical to actual human beings, but which have no conscious experience. Much of the consciousness literature focuses on considering how threatening philosophical reflection on such creatures is to physicalism. There is not much attention given to the converse possibility, the possibility of minds without bodies, that is, creatures who are conscious but whose nature is exhausted by their being conscious. We can call such a ‘purely conscious’ creature a ghost.

Zombies recently conjured by Searle and others threaten civilized (i.e., materialistic) philosophy of mind and scientific psychology as we know it. Humanoid beings that behave like us and may share our functional organizations and even, perhaps, our neurophysiological makeups without qualetative conscious experiences, zombies seem to meet every materialist condition for thought on offer and yet -- the wonted intuitions go -- are still disqualefied (disqualified for lack of qualia) from being thinking things. I have a plan. Other zombies -- good (qualia eating) zombies -- can battle their evil (behavior eating) cousins to a standoff. Perhaps even defeat them. Familiar zombies and supersmart zombies resist disqualefication, making the world safe, again, for materialism. Behavioristic materialism. Alas for functionalism, good zombies still eat programs. Alas for identity theory, all zombies -- every B movie fan knows -- eat brains.

In sum, then, Chalmers’s attempt to argue against physicalism based on the conceivability of zombies misses the mark. His version of conceivability does indeed imply possibility, but at the cost of making it unclear whether zombies are indeed conceivable.

Philosopher's zombies are hypothetical beings behaviorally, functionally, and perhaps even physically indistinguishable from normal humans, but who lack our consciousness. Many people seem to be convinced that such zombies are a real conceptual possibility, and that this bare possibility entails that understanding human consciousness must remain forever beyond the reach of science. However, the conceptual entailments of zombiehood have not been sufficiently examined. This brief article shows that any way of understanding the behavior of zombies that does in fact support the suggested entailment, leads to contradictions and absurdities. Zombies are _not_ conceptually possible.

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..

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.

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.

I argue that zombies are inconceivable. More precisely, I argue that the conceivability-intuition that is used to demonstrate their possibility has been misconstrued. Thought experiments alleged to feature zombies founder on the fact that, on the one hand, they _must_ involve first-person imagining, and yet, on the other hand, _cannot_. Philosophers who take themselves to have imagined zombies have unwittingly conflated imagining a creature who lacks consciousness with imagining a creature without also imagining the consciousness it may or may not possess.