What are the main arguments that emergence-based theories of consciousness can't solve the hard problem of consciousness?

Question

Ever since reading Douglas Hofstadter's Gödel, Escher, Bach as a teenager I've been fascinated by the idea that consciousness is an emergent property of physical systems. Roughly the claim is that consciousness is a physical property, but not one which can be reduced to lower-level physical properties of the sort described by biology, chemistry, and physics, etc. In particular, this view supports the idea that a human consciousness could be realized in a sufficiently advanced digital computer (although it does not imply that is possible to transfer an existing consciousness to a computer since that would additionally require that such a process preserves personal identity).

It seems like this idea is not taken very seriously among philosophers of mind who talk about the hard problem of consciousness and I'd like to know if there are some major arguments against it that I am missing.

Arguments like Searle's Chinese Room appear to convince many philosophers that the emergent property approach is a non-starter. However, I've never found the Chinese Room convincing. It relies on describing the situation in such a way that our attention is brought to the low-level functioning of the system (moving slips of paper around). When we view the system through this lens, we don't find anything that looks like qualia. However, the exact same is true if we look at the operation of a human being through a microscope. The emergent property theory of consciousness would say that only a higher-level view of the physical system can show us the relevant emergent property. If we try to adopt such a high-level of Chinese-room like scenarios (i.e., considering advance AGI systems) the intuitions start to become a lot less favourable to Searle's position.

The other argument I'm familiar with is Chalmers' zombie idea. I'm not familiar with all the details of his arguments so please let me know if I've missed something important. As I understand it, a strong zombie is one which is physically identical to a human but which lacks qualia. A weak zombie is one which is indistinguishable in terms of high-level behavior but differs in low-level physical states. Chalmers claims that a strong zombie is logically possible and bases some of his arguments on this claim. However, if it is true that in fact qualia are identical to emergent physical properties, then, assuming that "having qualia" is a rigid designator (see Kripke on necessary a posteriori or Putnam's "water is H2O"), strong zombies are logically impossible because they are based on an inconsistent hypothesis. If we assume that humans are conscious, then on the emergence view, human consciousness is logically identical to a high level property which is possessed by humans. Then the fact that strong zombies have all the physical properties of humans implies a fortiori they must possess the specific physical properties that in humans are identical to consciousness. By the logical law of identity, strong zombies must be conscious too, contradicting the other half of the strong zombie definition (this argument assumes that facts of logical identity are logically necessary).

If this is right, then only weak zombies remain as a challenge to the emergence view of consciousness. One way to construe the weak zombie view is to say that such a being displays all the high-level properties we identify as consciousness but lacks (by hypothesis) the low-level properties of all known conscious systems. By the emergence theory, there is no description that reduces the high-level physical properties, which are identical to consciousness, to low-level physical properties that are necessary and sufficient for consciousness. This is just what emergence implies, and it is compatible with both weak and strong theories of emergence. Therefore, it doesn't seem like weak zombies can even be defined rigorously if the emergence theory is true.

The only version of zombies that survives would be deceptive zombies. These are beings that in fact lack the high-level physical properties necessary for consciousness, but which nevertheless give off an illusory appearance of having those properties. We are all familiar with examples in the form of AI chatbots that could be taken as this sort of zombie. However, if we imagine that the deception is perfect and totally impenetrable no matter what type of further investigation we might do, then we are in the territory of general skeptical worries, analogous to Descartes' evil demon. It is always logically possible that our best efforts at gathering reliable evidence could fail due to some unforeseeable or gerrymandered epistemic setup. In the case of deceptive zombies we are imagining that despite all appearances of them having the relevant high-level physical properties, they still somehow lack them. Why would this present any specific issues for theories of consciousness that would not equally effect accounts of any type of emergent a posteriori knowledge? For example, it seems if we take deceptive zombies to be a problem, we at least have to take solipsism to be a major problem. Conversely, adopting a default and challenge response to skepticism in general, and other minds skepticism in particular, would be sufficient to render the deceptive zombie possibility epistemically irrelevant except in special cases.

Again, my question is, what I have a missed. I have a strong feeling that there must be some crucial arguments I've either not seen or not fully appreciated.

Answer 1

Short Answer

You have not missed anything. Lots of other philosophers have noticed this too. Non-reductive (I.E. emergent) physicalism is the plurality view of philosophy of mind among philosophers today, and is the majority position of physicalists.

First Tier of Complexities, (of Course, this is Philosophy!)

The Chinese Room, Mary the Color Scientist, Inverted Rainbow, and other thought problems challenging philosophy of mind orthodoxy, were primarily targeted at Functionalism, not emergent physicalism. They were successful, and Functionalism is no longer the dominant view among physicalists.

Of interest, the first functionalists asserted that Functionalism was NOT any different from reductive neural Identity Theory, but subsequent dualists, emergentists, and eliminative reductionists have been laying jaundiced eyes on that claim. Jaegwon Kim openly declares Functionalism to be a version of dualism, in which an Identity Theory is assumed between the Idealist "function" (an abstract logic entity, not a physical one) and consciousness. It may not be Cartesian dualism, and functions may be emergent from the physical, but Functionalism is NOT reductive physicalism. I will still treat it as different from what you are postulating, whatever Funcionalism's actual category in philosophy of mind.

At any rate, yes emergent physicalism avoids the problems that the Chinese Room postulates, because understanding Chinese can be a higher tier emergent phenomenon, and aspect of consciousness that is also emergent. However, that would require you to postulate that the Chinese Room is conscious, independent of the consciousness of the English speaking operator. Are you really willing to go that far?

We definitely seem to see emergence in many circumstances in the physical world. However, a further problem with emergence theories is -- there IS no emergence theory. What emerges, and under what circumstances, and what the causal relationship is between lower and higher tier phenomenon -- so far, we really have no clue about any of that. Claims of "emergence" are empirically LESS substantial than Cartesian Dualism. Is this actually a physical "theory", or is it better characterized as an invocation of "and then a miracle occurs" speculative evasion?

This ground has been trod before, and you are not going to like it

My favorite philosopher, Karl Popper, in the 1970s he tackled consciousness. He was formerly considered a giant of the 20th century, but lost much of his luster by addressing this issue.

The first thing he did, was challenge reductionist identity theory. He did it in two ways, first by noting the strong evidence for emergence in our universe, and spelling out a logic in which higher tier emergent phenomena are causal on their substrates (pressure, an emergent phenomenon, is causal on our pressure sensors on our pressure vessels, which trigger relief valves, letting lower tier gas molecules escape the pressure vessel, therefore reducing the pressure).

Second he looked at consciousness evolutionarily, observing that our conscious minds have the complex, sort of random architecture, but high effectiveness despite the poor architecture, which is characteristic of evolved structures. A tuned evolved structure is only possible if consciousness is causal. He also noted that we do basically all functions both consciously AND unconsciously, so functionally we could potentially have been unconscious zombies. Because of variational inheritance, if somehow our consciousness STARTED in sync with our neural function, due to luck that those functions happened to match our awareness, variation over generations would have caused some aspects of our consciousness to drift out of sync with our neural functioning, such that we could have completely random thoughts relative to what we actually are doing - or no thoughts at all for extended periods. Unless our consciousness is INDEPENDENTLY CAUSAL, the evolutionary tuning we see of our consciousness, could not have happened.

Popper therefore argued for emergence, at a time that emergence was seen as a crack-pot fringe view, and for VERY VERY STRONG emergence, where the emergent phenomenon, consciousness, was CAUSALLY INDEPENDENT of its substrate of neurons. Popper was willing to call this model what it is -- dualism. It is not Cartesian dualism, but instead an emergent psycho physical dualism. At the time, dualism was even more frowned upon than emergence. This book "The Self and Its Brain" destroyed Poppers reputation among his peers.

Subsequently, as you and many other physicalists have noted, emergence is a VERY attractive explanatory tool for addressing consciousness. And Strong Emergence for consciousness, in which consciousness is vaguely constrained by "supervenience" on neurology, is the most popular view among physicalists today. Few think through the evolutionary test case that Popper focused on.

Similarly among dualists, emergent psycho-physical dualism has now become the most popular view, although there doesn't seem to be any majority view today. Both groups have followed Popper, 50 years later. The only real difference is in whether consciousness is considered fully causally independent or sort of wishy-washy unspecifiable causal dependence on neurology.

My view is that the vague evasiveness of Supervenience, plus the strength of the evolutionary tuning argument, should nudge emergent physicalists over the line to become emergent dualists. But only a few have made that leap so far.

Summary wrap up

To summarize the objections, for emergent dualists, it is primarily the ill defined nature of emergence. For physicalists there are additional objections to the vagueness of supervenience, which seems deliberately crafted to try to avoid facing Popperian testing. And finally the physicalists face the evolutionary tuning of consciousness, which can not be explained if one treats “supervenes on neurology” as a stand in for “caused by neurology” or “identical with neurology”, which is the intended bait and switch that “supervenes” was invented to achieve in the first place.

Answer 2

Probably the challenging of emergence itself is the main issue.

The Chinese Room thought experiment is not supposed to be against emergence. Searle is a physicalist. I’m not sure if he’s a reductionist but I’ve never heard something to suggest he’s against emergence.

Whether reduction or emergence, the brain as a whole is implicated for consciousness for Searle, not just its computation, just its functional properties, nor just its behavior. All of this isn’t completely spelled out in just the Chinese room experiment but it’s elsewhere. How he notes the Churchlands backtracked on teaching their kids to say things like, instead of “I’m hungry”, say their glucose levels were low.

The person and the room are clearly not the same as a brain. That no subjective understanding like that of native Chinese speaker develops is thus not an indictment against emergence. It is to show the room is not like a brain, just like a stomach is not like a waste disposal in total.

The experiment is mostly about attacking computational theories of mind, and showing formal properties alone do not replicate our experiences. It is not aimed against non-dualistic emergence.

In general recent sentiment seems to be emergence is much harder to demonstrate in practice. Then you’ve got philosophers saying the hard problem is among the hardest problems ever, and it’s not obvious emergence is up to the task. Emergence is precisely when simple reduction rules fail, thus it is hard to demonstrate by nature. But it may win out by other options failing.

Answer 3

A sufficiently sophisticated deceptive zombie might be able to deceive itself into believing it is conscious.

(...or at any rate adopt an assumption to that effect as the most convenient stance in view of the need to find a way through the thickets of the physical and mental worlds that the zombie has to negotiate).

What would it be like to be such a zombie?