I'm currently reading Kim's The Mind-Body Problem after Fifty Years which tries to summarise how the MB problem has evolved and been approached the past few decades.

One of the very important terms that are used is supervenience. The mental supervenes on the physical, is a phrase that is often uttered. In other words, a mental state is dependent on a physical state. The issue I'm having is that I do not see how this works in a nonreductionist view. On page 8, Kim says

Moreover, and this was of crucial importance to the nonreductive physicalist, supervenience prima facie did not seem to commit us to reductionism: after all, many moral theorists [...] believed in the supervenience of the moral on the nonmoral, but rejected the reducibility of the former to the latter.

First of all, I don't know how I should picture this reference to moral. (An example would be useful.) How does moral supervene on the nonmoral. How does moral need the nonmoral? Second, how does this lead to an understanding of nonreductionist supervenience?

How can you say that something is completely dependent on a "lower-class" element that completely determines its properties, without reducing it to that element?

Note that I read this explanation, but that it didn't really clarify things for me. Is there a concrete example in which one could be said to follow a nonreductionist supervenience philosophy?

  • It is possible that the whole idea on nonreductive supervenience is incoherent, and that it's not just incoherent in your perception. I hope so, because that would be my view. Perhaps it's a little unfair, but I see it as wriggling on the hook in the face of threats to cherished materialist assumptions. .
    – user20253
    Jan 3, 2020 at 11:56
  • I wonder why he didn't go back a couple more thousand years. It's not as if anything new happened in the last fifty years other than a proliferation of terminology. .
    – user20253
    May 2, 2020 at 8:38

3 Answers 3


Non-reductionist supervenience is often called "emergentism," although that's a controversial term, and one has been deployed in sometimes contradictory ways (some "emergentists" would consider themselves reductionist, and some would not).

Much of it comes down to disagreements over what constitutes reductionism. Is it reductionist to state that something complex is made of simpler parts? Or does reductionism also state that it is best understood by understanding the simpler parts? Or does reductionism state that it is only understood by understanding the simpler parts?

For instance, even in the case that the mental entirely supervenes on the physical structure of the brain --is an emergent property of the brain--, it's arguable that we will never gain an useful understanding of it by just studying the brain at the cellular level. One person might call this non-reductionist supervenience, another might not.


I would say you very probably have direct experience of a non-reductionist supervenience, unless you do actually perceive your own self as "nothing more than" the collection of cells, chemicals, electrical signals, etc. of which you consist. "Living being" supervenes non-reductively on those other collections.

It seems to me in general that non-reductive supervenience just means that there are really two different sets of phenomena (being, collection of cells) that operate "in parallel" with each other, rather than one being a mere "illusory" phenomenal result of the actions of the other, only.


Consider Newtonian dynamics. What happens when forces are truly and completely equal, say in the case of the proverbial rolling sphere balanced at the top of the perfectly smooth hill. The system simply does not say, the behavior is not determined, and there are multiple options. Now back off to old-school quantum mechanics. The set of outcomes that are truly just not determined is slightly wider, as what is traditionally considered the 'vibrational' or 'rotational' 'phase' is not the regular and repeating pattern that those concepts would lay upon it.

So to say that the outcome does not supervene upon the physics would be false, but it would also be false to claim that we could reduce the outcome to the physics: There are cases where the physics does not fully determine the outcome.

Now, obviously, we are only talking about our past theories of physics, and not about the process of nature itself. But if such a configuration (supervenience without reduction) can exist in our theories, it may exist in reality. (People like Roger Penrose clearly presume that it does.)

This kind of relationship is presumed by many moral theories. Morality supervenes upon emotion and logic, but there is an element of morality that is not properly completely determined by those. The right thing to do is still open to random influences, leaving many paths open once both logic and emotion have been thoroughly accounted for, even though there are really no other inputs. Or there are clashes of balanced intensity between logical and emotional arguments, which still get resolved somehow.

We may notice the gaps in justified feelings of guilt occurring after the fact. There is a moral quality that we may not have been able to account for at the time, but which still lays a debt upon us. If we could have predicted the moral effects of the action given our state and our information, we would have avoided it, but we cannot dismiss it.

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