Emergentism and the PSR
Disclaimer: Philosophy of Mind is not my specialty. So perhaps I am about to step in it with this post. But I really want to work out my reasons for why I find emergentism suspect. Also, I realize that there are alternative ways in which philosophers define terms like “reduction” and “emergence”. Perhaps the way I am using these terms leads me to the problems I see. Comments, as always, are welcome.
A defensible version of the principle of sufficient reason, PSR, says something like: every contingent fact has an explanation.1 That I have a conscious mind is a contingent fact, so I would expect that it would have an explanation, and I would be very much unsatisfied by a theory of mind that rested on a violation of the PSR—asserting that minds are inherently inexplicable brute facts. My question is whether any physicalistic theory based on emergentism offers us an explanation for the mind. That is, can a non-reductive physicalism based on emergent properties cohere with the principle of sufficient reason?
Jaegwon Kim says that one of the central doctrine of emergentism is that some property p is emergent only if p is not explainable in terms of its “basal conditions”.1 Furthermore, the way in which a property emerges from its basal conditions cannot be predicted through a mere analysis of the basal conditions. Rather, it is only through a Humean constant conjunction that the emergentist thinks we can learn to anticipate which kinds of emergent properties correlate with which configurations of basal conditions.
Put simply, the emergentist appeals to the idea that p is “emergent” in an effort to explain how p can be ontologically dependent on a certain set of physical basal conditions, B, while not being reducibly explained by B.
But if p cannot be reducibly explained by B, we might begin to wonder whether the claim “p is emergent” can genuinely function as an explanation.
Suppose we bite the bullet and assert that, since it cannot appeal to B for an explanation, emergentism simply rejects that there can be an explanation for p. I think three untoward consequences follow: a) emergentism becomes an inherently controversial position, since it would implicitly entail the failure of the PSR, b) in rejecting the PSR, emergentism becomes a black-box rather than a genuine explanation for p; i.e. it merely states the triviality that p exists while masquerading as an explanation for why p exists, and c) in rejecting the PSR there could be no explanation for the constancy of p, given B, rather than some non-p alternative. Any appeal to B as the sufficient explanation would erode the central claim of emergentism—that it is a non-reductive theory.
With these consequences in mind, I think the emergentist would want to say that p is explicable, just not reducibly explicable to its physical basal conditions.
Given that p is contingent and has an explanation, it cannot function as its own explanans. Therefore, its explanation must come from something else. But assuming that the explanation cannot be sourced in B, we must rule out all of those physical constituents upon which p ontologically depends. So could the explanans for p include some other physical entities, laws, or processes, call it “E”, that do not belong to the set that comprises B? How would that work? For, it would seem that p would have to be ontologically dependent upon E in some way, and so E would necessarily be a constituent of B. For if E failed to obtain, the explanans for p couldn’t possibly obtain. And if p were to obtain sans its explanans, how could E genuinely serve as the explanans? The necessity of E for p suggests physical ontological dependence. So if emergentism doesn’t presume the failure of the PSR, and p is explained by E, then E is a constituent of B. Yet, any from of emergentism where p is explained by E, and where E is a subset of B, is merely a form of reductionism.
Here we have an inconsistent triad:
1) Physicalism is obtains.
2) Emergentism is obtains.
3) The Principle of Sufficient Reason obtains.
At most, two of the three propositions above can be true. For instance, if everything is physical, and emergentism requires that B cannot explain p, then the PSR fails. For any proposed physical explanation for p would be subsumed into B as part of the physical basal conditions, and so must be ruled out as an explanation for the emergent property.
Likewise, if everything is physical, and the PSR obtains, for any contingent p, p can be reductively explained by B. In which case, emergentism fails.
Finally, if emergentism and the PSR are true, physicalism is false. For, such a case would require that there be a non-physical explanation, one that cannot be subsumed into B.
Given the above analysis, it seems to me that emergentism, as a physicalistic theory of mind, is susceptible to the previously mentioned untoward consequences. Implicit within the theory is a failure of PSR. And so emergentism, at best, functions as a black-box pseudo-explanation. To say that the mind emerges from the brain is just to say that there cannot be an explanation for why minds correlate with brain-state basal conditions. Furthermore, it cannot account for the constancy between brain states and conscious mental states. Why shouldn’t brain-state basal conditions give rise to other possible emergent properties rather than mental states?
If one were to take the PSR seriously, and maintain one’s commitment to emergentism, then one would have to appeal to at least some non-physical facts as part of the explanation for how the mind might emerge from correlated physical basal conditions. But if the point of emergentism is to avoid the appeal to souls, formal causes, God, and the like, this route is simply not available.
It is for these reasons that I do not see emergentism as a viable non-reductive physicalistic theory of mind.
1See A. Pruss. 2006. The Principle of Sufficient Reasons. New York: Cambridge University Press.
2J. Kim. 1997. “Explanation, Prediction, and Reduction in Emergentism”. In Intellectica Vol. 2. No. 25. pp.1-2.