I think a lot of people misunderstand David Chalmers. Given Chalmers's popular characterization I don't think many people would be aware that David Chalmers allows the possibility that Searle’s Chinese Room is conscious^[1]. His public image is that of the foremost advocate of dualism; something associated with wishy-washy quasi-religious theories of consciousness which most people would assume reject something like Searle's Chinese Room out of hand. Of course that is as inaccurate as saying Hume opposed the Enlightenment because he saw non-rational beliefs as necessary for understanding.

Chalmers is a minimal dualist, arguably practically a physicalist. Chalmers’s dualism is in many ways simply an end run around all of the logically unanswerable questions that tangle up philosophical discussions of consciousness, one such being the sheer existence of consciousness as discussed in the problem of p-zombies. Chalmers comes to the same conclusion as the people who purport to argue against him on this forum; that these angels on the head of a pin type arguments are uninteresting and must be assumed away.

And this is the answer to Eliezer Yudkowsky’s question in Zombies! Zombies? “To postulate this stuff of consciousness, and then further postulate that it doesn't do anything—for the love of cute kittens, why?” The answer is to assume away the tangle of thorny questions around consciousness to get at more interesting issues. Allow me to further explain:

Hume points out that nothing guarantees causal induction. Nothing guarantees that the patterns of the past will repeat in the future. This was not a universal belief in his time and he was principally arguing against the continental rationalists of Descartes and Leibniz who did believe that effects followed from causes necessarily in all possible worlds. This argument from historical Rationalists against Hume was nearly a perfect parallel to Yudkowsky's criticism of Chalmers which asserts that a system organized like a brain must be conscious in all possible worlds. Empiricists, following Hume’s opposition to Rationalism, acknowledge the problem of induction but assume it away in order to have empirical thoughts including that subset of empirical thoughts known as scientific thoughts.

Chalmers makes a foundational assumption for understanding consciousness very similar to Hume's causal induction in what he calls his principle of organizational invariance; in essence that systems which are organized similar to human brains have consciousness similar to human brains (your brain in particular) ultimately by pushing around some ineffable “consciousness juice” substance. This foundational assumption circumvents all of the thorny questions which tangle around consciousness in spite of our certainty on physical causation; the sheer existence of consciousness demonstrated with the example of philosophical zombies, the inversion of qualia i.e. the idea of that your red may be somebody else’s green, fading qualia where there is an uncertain demarcation when you ship of Theseus a person's brain into a cyborg brain, dancing qualia where qualia change their character moment to moment and you just remember the new qualia in your memories, etc.

In a very similar way causality assumes moments flow one to another pushed around by a kind of “causality juice,” i.e. energy which Chalmers explicitly analogizes to his “consciousness juice” although without my exact phrasing (he’d compare energy to “irreducible consciousness” rather than “consciousness juice”). Chalmers makes the point that though physics describes in detail how energy is manipulated it does not say what energy itself actually is; in physics energy is an irreducible concept. In a very similar way to how causal induction assumes that we can project from what we can observe, i.e. our memory of the past, into what we can never observe, i.e. the future, Chalmers is making an assumption on consciousness to bridge from what we can observe, i.e. our own experience, into what we can never observe, i.e. the experience of anything else.

And if we think about it Chalmers’s foundational assumptions on consciousness are even more foundational than physical causal induction. Physical causal induction doesn't actually tell us what our future experiences will be. While it may prescribe the actions of the external universe, it is silent on how our perceptions of that universe will be translated into our qualitative experience or even if it will. Have you considered that perhaps in the past you were a p-zombie and only now have attained a brief moment of consciousness where your memories tell you that you were not a p-zombie in the past? A brief moment which may soon be ended by another period of existence as a p-zombie? Your existence to this point may have consisted of a very regular inductively repeating oscillating pattern of conscious moments and moments of p-zombie existence.

Physical causality makes no statements about this possibility nor any of the other problems of consciousness. I think color inversion is likely something most readers (on Lesswrong) would have already considered possibly true despite our causal universe. The principle of organizational invariance gives a similar foundational justification to believe color inversion is impossible as causal induction gives to believe gravity ceasing its operation in the next moment is impossible.

Chalmers's principle of organizational invariance makes a predictive assumption on these experiences in a very similar way to the way our assumption of induction allows us to make predictive empirical statements. In that sense it is even more predictively deterministic than causality. Even in a primordially chaotic universe where there is no causal connection moment to moment we could use Chalmers's principle of organizational invariance to tell us what in any given moment the conscious experience of a mind in such a universe would be.

I think Eliezer Yudkowsky and Chalmers agree in a similar way to how Hume agreed with The Enlightenment. Both Yudkowsky and Chalmers see the issue of p-zombies as unimportant, something to be assumed away. When Chalmers says that p-zombies are conceivable he is basically just throwing a bone to people concerned about such things before ultimately stoppering up any sort of discussion with an assumption. In this sense he represents a kind of final concession to older modes of thought before sealing it away into a separate realm, much like Hume’s empiricist project to seal off Aristotelian mysticism from modern scientific inquiry behind our irrational assumption of causal induction.

While the principle of organizational invariance may suggest that p zombies are in some sense impossible, it really boils down to semantics around the word conceivable. Is a non-causal universe conceivable? Descartes and early Rationalists would say no. What would it mean? In what sense would it be a universe? It would just be a disconnected series of circumstances; arguably this would be identical to passing sequentially through a series of distinct universes. 

Early Rationalists’ disbelief that the notion causality was an assumption and not simply inherently true in all possible worlds was the crux of Hume’s discussion of the problem of induction. Our historical namesakes made a similar argument to Yudkowsky’s Zombies? Zombies! against the problem of induction being at all a problem.

Of course Hume is presently considered convincing. It seems that generally when we are speaking about conceivability in a philosophical setting we are talking about not having at present a contradictory statement to the conceivable statement from our existing believed empirical theory^[2]. In this way we can conceive that a long tail digit of pi could be 6 rather than its actual value of 9 if we haven't personally worked out pi to that precision.

Personally, I don't think these kinds of semantic arguments are that interesting. Clearly there is something that compelled Hume to discuss the problem of induction and which compels us to study Hume. Is this compelling thing a “conception” of a universe which does not obey causality? Do we gain anything by couching this in further philosophical caveats like saying this is a “seeming” of a conception? 

I don't think so.

Postscript: This is somewhat of a preamble to my next post on a physicalist account of sensory qualia. I encourage readers to take a look at my previous post explaining how the thalamus is the seat of consciousness, temporally binding our experience into a series of discreet moments and being the location of conscious decision making.

1. ^{^}

   After describing a slow gradual replacement of a biological brain into a Chinese Room on page 325 of The Conscious Mind:

   It is therefore reasonable to conclude that the final system has precisely the conscious experiences of the original system. If the neural system gave rise to experiences of bright red, so will the system of demons, and so will the network of pieces of paper mediated by a demon. But of course, this final case is just a copy of the system in the Chinese room. We have therefore given a positive reason to believe that that system really has conscious experiences, such as that of understanding Chinese or of experiencing red.

   Chalmers, David J. The conscious mind: In search of a fundamental theory. Oxford Paperbacks, 1997.

2. ^{^}

   Perhaps this is like a philosophical axiom of choice: when we can't disprove the existence of some conditions we just assume/say that we can choose “conceive” a thing that fulfills those conditions.