Ever since sharing Ned Block’s talk on it, phenomenal consciousness has been on my mind. This week, I decided I needed to go back to the main spokesperson for the issue of subjective experience, David Chalmers, and his seminal paper Facing Up to the Problem of Consciousness.
I have to admit I’ve skimmed this paper numerous times, but always struggled after the main thesis. This time I soldiered on in a more focused manner, and was surprised by how much I agreed with him on many points.
Chalmers starts off by acknowledging the scientifically approachable aspects of the problem.
The easy problems of consciousness include those of explaining the following phenomena:
- the ability to discriminate, categorize, and react to environmental stimuli;
- the integration of information by a cognitive system;
- the reportability of mental states;
- the ability of a system to access its own internal states;
- the focus of attention;
- the deliberate control of behavior;
- the difference between wakefulness and sleep.
But his main thesis is this point.
The really hard problem of consciousness is the problem of experience. When we think and perceive, there is a whir of information-processing, but there is also a subjective aspect. As Nagel (1974) has put it, there is something it is like to be a conscious organism. This subjective aspect is experience. When we see, for example, we experience visual sensations: the felt quality of redness, the experience of dark and light, the quality of depth in a visual field. Other experiences go along with perception in different modalities: the sound of a clarinet, the smell of mothballs. Then there are bodily sensations, from pains to orgasms; mental images that are conjured up internally; the felt quality of emotion, and the experience of a stream of conscious thought. What unites all of these states is that there is something it is like to be in them. All of them are states of experience.
My usual reaction to this is something like, “You’re holding up two puzzle pieces that fit together. Everything you need is in what you call the ‘easy problems’!” In Chalmers’ view, this puts me into a group he labels type-A materialists, a group including people like Daniel Dennett and Patricia and Paul Churchland.
The distinction between the two viewpoints is best exemplified by remarks Chalmers makes in his response paper to the many commentaries on the Facing paper. Daniel Dennett in particular gets singled out a lot.
Dennett’s argument here, interestingly enough, is an appeal to phenomenology. He examines his own phenomenology, and tells us that he finds nothing other than functions that need explaining. The manifest phenomena that need explaining are his reactions and his abilities; nothing else even presents itself as needing to be explained.
This is daringly close to a simple denial –
(Note: Dennett’s commentary on Chalmer’s paper is online.)
However, Chalmers later makes this admission:
Dennett might respond that I, equally, do not give arguments for the position that something more than functions needs to be explained. And there would be some justice here: while I do argue at length for my conclusions, all these arguments take the existence of consciousness for granted, where the relevant concept of consciousness is explicitly distinguished from functional concepts such as discrimination, integration, reaction, and report.
Here we have a divide between two camps, one represented by Chalmers, the other by Dennett, staring at each other across a gap of seemingly mutual incomprehension. One camp sees something inescapably non-functional that needs to be explained, the other sees everything plausibly explainable in functional terms. Both camps seem convinced that the other is missing something, or maybe even in denial.
Speaking from the functionalist camp, I will readily admit that I do feel the profound nature of subjectivity, of the fact we exist and experience reality with a viewpoint. I don’t feel like an information processing system, a control center for an animal. I feel like something more. The sense that there has to be something in addition to mere functionality is very powerful.
The difference, I think, is that functionalists don’t trust this intuition. It seems like something an intelligent social animal concerned with its survival and actualization might intuit for adaptive motivational (functional) reasons. And it seems resonate with many other intuitions that science has forced us to discard, like the sense that we’re the center of the universe, that we’re separate and above nature, that time and space are absolute, or many others.
But are we right to dismiss the intuition? Maybe the mind is different. Maybe there is something here that normal scientific investigation won’t be able to resolve. After all, we only ever have access to our own subjective experience. Everything beyond that is theory. Maybe we’re letting those theories cause us to deny the more primal reality.
Perhaps. In the end, all we can do is build theories about reality and see which ones eventually turn out to be more predictive.
Anyway, as I mentioned above, I’ve always struggled with the paper after this point, generally shifting to skim mode. This time, determined to grasp Chalmers’ viewpoint, I soldiered on, and got the surprises I mentioned.
First, Chalmers, while being the one to coin the hard problem of consciousness, does not see it as unsolvable. He’s not one of those who simply say “hard problem”, fold their arms, and stop. He spends time discussing what he thinks a successful theory might look like.
In his view, experience is unavoidably irreducible. Therefore, any theory about it would likely look like a fundamental one, similar to fundamental scientific theories that involve spin, electric charge, or spacetime, while accepting these concepts as brute fact. In other words, a theory of conscious experience might look more like a theory of physics than a biological, neurological, or computational one.
Such a theory would be built on what he calls psychophysical principles or laws. This could be viewed as either expanding our ontology into a super-physical realm, or expanding physics to incorporate the principles.
But what most surprised me is that Chalmers took a shot at an outline of a theory, and it’s one that, at an instrumental level, is actually compatible with my own views.
His theory outline has three components (with increasing levels of controversy).
The principle of structural coherence. This is a recognition that the contents of experience and functionality intimately “cohere” with each other. In other words, the contents of experience have neural correlates, even if experience in and of itself isn’t entailed by them. Neuroscience matters.
The principle of organizational invariance. From the paper:
This principle states that any two systems with the same fine-grained functional organization will have qualitatively identical experiences. If the causal patterns of neural organization were duplicated in silicon, for example, with a silicon chip for every neuron and the same patterns of interaction, then the same experiences would arise.
This puts Chalmers on board with artificial intelligence and mind copying. He’s not a biological exceptionalist.
The double-aspect theory of information. This is the heart of it, and the part Chalmers feels the least confident about. From the paper:
This leads to a natural hypothesis: that information (or at least some information) has two basic aspects, a physical aspect and a phenomenal aspect. This has the status of a basic principle that might underlie and explain the emergence of experience from the physical. Experience arises by virtue of its status as one aspect of information, when the other aspect is found embodied in physical processing.
In other words, the contents of conscious experience are built from functional neural processing, functionality which is multi-realizable, and experience itself is rooted in the properties of information.
There are two other aspects of this theory that are worth mentioning. First, note the “information (or at least some information)” phrase. This shows Chalmers’ attraction to panpsychism.
Honestly, if I had the conviction that the existence of experience was inherently unexplainable in terms of normal physics, panpsychism would be appealing. Seeing nascent experience everywhere but concentrated by certain functionality, frees someone with this view from having to find any special physics or magic in the brain, providing a reconciliation with mainstream neuroscience. Indeed, under Chalmers’ principles, it’s actually instrumentally equivalent to functionalism.
The other aspect worth mentioning is the danger of epiphenomenalism, the implication that experience is something with no causal power, which would be strange since we’re discussing it. Chalmers acknowledges this in the response paper. If the physics are casually closed, where does experience get a chance to make a difference?
Chalmers notes that physics explores things in an extrinsic fashion, in terms of the relations between things, not intrinsically, in terms of the things in and of themselves. In other words, we don’t know fundamentally what matter and energy are. Maybe their intrinsic essence includes an incipient experential aspect that contributes to their causal effects. If so, it might allow his theory to avoid the epiphenomenalism trap. (Philip Goff more recently discussed this concept.)
To be clear, Chalmers’ theory outline carries metaphysical commitments a functionalist doesn’t need. However, that aside, I’m surprised by how close it is to my own views. I have no problem with his first two principles (at least other than the limitation he puts on the first one).
The main difference is in the third component. I see phenomenal properties as physical information, and phenomenal experience overall as physical information processes, without any need to explicitly invoke a fundamental experential aspect of information. In my mind, experience is delivered by the processing, but again that’s the functionalist perspective. The thing is, the practical results from both views end up being the same.
So in strictly instrumental terms, my views and Chalmers are actually in alignment. We both turn to neuroscience for the contents of consciousness, and both of us accept the possibility of machine intelligence and mind copying. And information is central to both views. The result is that we’re going to make very similar, if not identical predictions, at least in terms of observations.
Overall then, my impression is that while Chalmers is convinced there is something in addition to the physics going on, at least known physics, he reconciles that view with science. Indeed, if we interpret the non-physical aspects of his theory in a platonic or abstract manner, the differences between his views and functionalism could be said to collapse into language preferences. Not that I expect Chalmers or Dennett to see it this way.
What do you think? Am I being too easy on Chalmers? Or too skeptical? Or still not understanding the basic problem of experience? What should we think about Chalmers’ naturalistic and law driven dualism?