Wednesday, November 14, 2018

Emergence and the epistemological gap

After reading O’Connor and Churchill’s piece on emergence, one of my very smart undergraduate students commented that it follows from such emergentist views that one could know the mental facts from the physical facts. Here I will argue for this and discuss an unhappy consequence for the causal emergentist.

The causal emergentist thinks that mental properties are not physical, but they causally emerge from complexes of physical properties of a physical entity.

So, now, suppose that physical entity e has a causal power C to produce mental property M when it has a complex P of physical properties. This causal power C will then either be a physical or a non-physical property of e. If it is a physical property of e, then by knowing the physical properties of e, one can know that e has the causal power to produce M. And that, in turn, means M is knowable from physical properties. On the other hand, if C is non-physical, then we do not have emergence of the mental from the physical: we have emergence of the mental from the physical and non-physical. So, if we have genuine emergence of the mental from the physical, then in knowing the physical, we will know the mental.

The unhappy consequence of this is that qualia-based epistemological gap arguments against physicalism apply against causal emergence, since we could suppose M is a quale, and then knowing all about C will include knowing all about M.

Causal emergence may fare a little better with respect to zombie-type arguments. If an entity has an exact duplicate of your physical properties, it will have an exact duplicate of the physically-based causal powers, and hence it will have the causal power to make mental properties emerge. However, it is logically possible that these mental properties will in fact fail to emerge, because it is logically possible that some external causal power blocks the causal powers of the duplicate from achieving their effects. One could even imagine a whole world that is an exact physical duplicate of this one but where nobody physical has mental powers, because some non-physical entity blocks the mental-emergence powers of all the physical beings. So I guess this does some justice to zombie intuitions. But note that if the possibility-of-zombies intuition is satisfied by a non-physical entity blocking mental powers, then a dispositional functionalist could do justice to the zombie intuition by imagining a world just like this one, but where a non-physical entity changes our dispositional properties in the way of Frankfurt’s neurosurgeon. And it’s not clear that that really does justice to the zombie intuition. Maybe.

The above argument against causal emergentism supposes that knowing a cause implies knowing the range of its effects. That is correct on causal powers views of causation. It is not true on Humean views of causation. So a causal emergentist could simply adopt a Humean view of causation. It is also not true on views on which causation depends on laws of nature extrinsic to the particular things in the world. But the causal powers view is the correct one. (And it is one that O’Connor and Churchill embrace.)

What if the emergence relation is not causal in nature? Then it is still a dispositional fact about our physical entity e that it comes to have mental property M when it comes to have a complex P of physical properties. This fact seems like it should be grounded in the properties of e. These properties had better be physical, because the motivation for the theory seems to be that our non-physical properties emerge from our physical ones. And now we still have the danger that by knowing these physical grounds, one can come to know the dispositional fact, and hence come to know M. Perhaps there is a way out of this danger.

Perhaps the best way out for the emergentist, causal or not, is to acknowledge a non-emergent non-physical property in each minded entity grounding the emergence dispositions.

Of course, none of this is a problem if one is unimpressed by qualia-based epistemological gap arguments.

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