The dynamical combination problem

Panpsychism is the idea that basic physical entities are essentially micro-consciousnesses and that our macro-consciousnesses result from combining the phenomenal natures of the physical entities that constitute us. The view faces the combination problem: how do simple, discrete micro-consciousnesses combine to produce complex, unified macro-consciousnesses? This problem has been much discussed, but there’s an aspect of it that has, I think, been relatively neglected. Here it is.

It looks like a sensible methodological assumption that if two entities are qualitatively identical from a physical point of view, then they are phenomenally identical too. If panpsychists don’t make this assumption, then it’s hard to see how they could construct anything like a science of consciousness. If panpsychism is true, then we are acquainted with only a tiny fraction of phenomenal reality — the portions that constitute our consciousnesses. The rest can be known only indirectly, by inference from corresponding physical features. But if phenomenal properties could vary independently of physical ones, then there would be no stable phenomenal-physical correspondences, and the bulk of phenomenal reality would not be even indirectly accessible to us. This could be case, but if it is, then there is no hope of explaining consciousness.

If the assumption is true, however, then it follows that there is very little phenomenal variation at the fundamental level. There are only a few types of fundamental particles, and all tokens of these types are qualitatively identical from a physical point of view, differentiated only by their spatio-temporal location. Every up-quark is physically identical to every other up-quark. So all tokens of each particle type are phenomenally identical too. (Differences in their spatio-temporal location are relational ones and cannot affect their intrinsic natures.)

It follows that fundamental phenomenal reality is quite uniform. There will just be a few different phenomenal ‘notes’ played billions upon billions of times. The combination problem is thus doubly difficult: the phenomenal elements from which our macro-consciousnesses are formed are not only simple but few in number, and we must explain how variety emerges from uniformity as well as how richness emerges from simplicity.

But this isn’t all. There is another aspect to the problem, which looks even more challenging. It’s a dynamical aspect. For if our assumption is sound, the phenomenal properties of the fundamental entities never alter. Fundamental particles do not change or age. So, except in exotic circumstances where particles are created or destroyed, the overall phenomenal soundscape stays the same, unaffected by particles’ changes in location (which, again, are irrelevant to their intrinsic natures). The fundamental phenomenal world is almost completely static. How, then, does a dynamical, ever-changing human consciousness emerge from a static phenomenal base? We might call this the dynamical combination problem.

Of course, all this assumes a rather old-fashioned picture of the microphysical world as one of discrete fundamental particles located in spacetime. The problem may look different, and perhaps more tractable, if we adopt a more sophisticated physics.

If you have any thoughts on this problem or any references to relevant discussions in the panpsychist literature, do please post them in the comments.

Essential-state materialism and multiple realizability

Suppose that phenomenal properties, such as the intrinsic feel of pain, are not physical properties in the standard sense. It’s a fair bet that science will be able to identify physical causes for all the effects of experience. So how can phenomenal properties have any effect on us? How does the feel of our experiences make a difference to us?

Panpsychists have a neat answer to this. They say that the phenomenal properties of experience are the intrinsic natures of the physical states that play the functional roles of the relevant experiences, including causing their characteristic effects. So (to use a hoary example) if the firing of C-fibres in the brain is the physical state that plays the functional role of pain, then the feel of pain is the intrinsic nature of C-fibre firing. Assuming this intrinsic nature does at least some of the causal work in producing pain effects, then it follows that the feel of pain is a cause of pain behaviour.

This view is, in effect, a radical form of type identity theory or central-state materialism. It says that pain is type identical, not with the brain state that plays the pain role, but with the essential nature of that brain state. We might call the view essential-state materialism.

And like type identity theory, the view faces an objection from multiple realization. The same functional role could be played by different physical states. This may actually happen in other creatures — octopuses, perhaps — and we can easily imagine it happening in us. The brain is highly plastic, and existing structures can be recruited to play new roles in response to damage. In the future, we may even be able to replace damaged brain structures with artificial ones that play the same role.

This poses an obvious problem for the essential-state view. If pain is the essential nature of C-fibre firing, then creatures who lack C-fibres cannot feel pain, even if they have functionally identical states and respond exactly as if they do feel pain. This is a counterintuitive, and possibly cruel, view. How do panpsychists respond?

It is implausible to say that all the physical states that could play the pain role have the same intrinsic nature. (And even if it weren’t, it wouldn’t solve the problem, since those states could also play other functional roles, with the result that pain could cause behaviour quite unrelated to pain, which is equally counterintuitive.) And of course panpsychists can’t say that the phenomenal nature of a physical state changes with the functional role it plays, since that would mean that a physical state’s phenomenal nature is not intrinsic to it.

I’d be grateful for any thoughts on this problem or for references to discussions of it in the panpsychist literature.