Wednesday, November 23, 2011

Epiphenomenal Explanations

Explanations come in various different forms. Sometimes we are interested in strictly causal "actual sequence" explanations, which tell us which particular causal forces happened to bring about the outcome in question. Other times we want a higher-level, "robust process" explanation, identifying the broader patterns that secure similar outcomes across nearby possible worlds (though the particular "sequence" details may vary, compatibly with maintaining the same high-level pattern). These explanatory patterns might be considered 'causes' in a weaker sense -- they're certainly eligible to feature in true "because" claims, though there's an obvious sense in which such abstracta lack the direct causal "oomph" of their particular physical constituents. Further, I think we sometimes appeal -- esp. regarding ethics and phenomenal consciousness -- to what might be called "correlative" explanations, when we speak of some familiar epiphenomenal byproduct as being explanatory, even when strictly speaking it is a correlated physical state that provides the causal "oomph".

Consider the following picture of epiphenomenal consciousness:
We may think of mental states as having both physical and experiential components: their physical effects are due entirely to the physical aspects of our thoughts. The non-physical (experiential) component, on the other hand, constitutes what it feels like to be in that state. There's then an obvious sense in which our mental states have causal effects, insofar as their physical aspects do. That doesn't require that the causal 'oomph' come from the experiential aspect -- indeed, how could it? Experiential feels aren't the kinds of things that push atoms around. You need other particles to accomplish that!

On this view, we may (speaking loosely) say that I pulled my hand away from the hot stove "because it hurt", and this can be perfectly informative, without implying that the hurty feel itself provided the causal force that moved my hand. It's a reasonably robust explanation because across a wide range of nearby possible worlds, I flinch away from things that cause me certain kinds of pain. This is so even though the underlying physical state is what's really doing the causal work, such that if you tweaked the psycho-physical bridging laws to turn this into a zombie world, my behaviour (following my brain states) would remain unchanged. (Of course, with the robust correlation gone, the explanation "because it hurt" would no longer be available in the zombie world. My point is just that this distant possibility of correlative breakdown doesn't undermine the use of correlative explanations in the actual world.)

I think that similar "correlative" explanations are available to metaethical epiphenomenalists. Even non-naturalists who deny causal powers to abstract moral properties can nonetheless follow the likes of Sturgeon and Railton in using ethical categories in robust-process explanations. It's (in part) because Hitler was evil that his rise to power led to such atrocities. It's (in part) because American slavery was so strikingly immoral that the abolition movement gained widespread support. This isn't to say that the property of "evilness" exerted physical pressure on the world. Again, the underlying natural properties (lack of compassion, etc.) provided the causal "oomph". It's just that the moral properties correlate with important patterns of natural properties -- patterns whose various possible instantiations may reliably lead to human suffering, and to righteous indignation and outrage on the part of fitting moral agents who are attuned to those patterns.

This is all to suggest that familiar objections to (phenomenal and metaethical) epiphenomenalism seem overblown. Sure, it'd be crazy to deny (e.g.) the commonsense idea that I pulled away from the stove "because it hurt". But we've seen that epiphenomenalists need not deny this. The question then becomes: Is it so clear that commonsense commits us to the stronger claim that the hurtiness is what must provide the causal 'oomph' in such a case? I think that this is not at all clear, and that the epiphenomenalist's rival account seems perfectly sensible on reflection. But perhaps my intuitions are corrupted by theory, so I invite others to chime in with their thoughts...


  1. I've said essentially this before, but it does seem to me that the hurtiness must be what provides the causal "oomph." But then you already knew that I find functionalist views intuitive and plausible and non-reductionist views mysterious and unintuitive.

  2. Can I give a correlative explanation of the storm in terms of the barometer reading?

  3. It seems not. And one can multiply examples of that kind, so I agree that something does not become explanatorily relevant merely by being correlated with something else that is. So it's worth asking what makes the cases of qualia and normativity different.

    One promising proposal is that it is the intimacy of the link between the physical and the phenomenal/normative that lets us use the latter as explanatory 'stand-ins' for the former. They are not merely correlated, but stand in fairly strong supervenience relations (the normative metaphysically supervenes on the non-normative, and the phenomenal at least nomologically supervenes on the physical).

    That's a first pass, at least. I'd welcome further thoughts / suggestions.

  4. But what difference between supervenience and mere correlation makes the former, but not the latter, explanatory? (Jackson and Pettit, who defend a model of the sort you describe, would presumably want to say something about providing information about causal history. But I don't see how this is a difference between the two cases—after all, I say something informative about the causal history of the storm when I inform you that the causes, such as they are, have the effect of making the barometer read a certain way).

  5. *shrug*. I'm not sure if much actually turns on it though. If we found a culture that did speak of a storm occurring "because of" the state of the barometer, I wouldn't be in any rush to charge them with making a philosophical error (so long as they merely meant it in the weak sense described in this post, and had an accurate conception of the actual sequence of events). It'd just seem a slightly funny way of talking. At worst: it's potentially misleading to the unenculturated ear.

    For the same reason, you might advocate that people refrain from using moral or phenomenal features in "because" claims. I'm not sure if that's really advisable -- it seems an often convenient shorthand (which might turn out to be the difference from those other cases), but I'm not too concerned either way.

    The message I am concerned with: Given that we (may) merely mean these weak and loose claims when we say things like "I pulled away because it hurt", such thoughts aren't necessarily incompatible with epiphenomenalism. Of course, it's up to the reader to assess whether they also find some stronger claim (genuinely incompatible with epiphenomenalism) to be commonsensical.

  6. If there isn't after all a principled difference between the barometer explanation and the pain explanation (assuming epiphenomenalism), then it seems that this can't be right: "These explanatory patterns might be considered 'causes' in a weaker sense". So if the commonsensical notion of "because" is causal, it is incompatible with epiphenomenalism. Do you agree?

  7. I agree that epiphenomenalism is inconsistent with ascribing strict causal 'oomph' to qualia. But I don't want to rule out the possibility that one might speak of mental 'causes' in some weaker sense compatible with epiphenomenalism. (I also suspect that talk of "the commonsensical notion of 'because'" is misleading; I think the term is commonly used in multiple ways. Compare, e.g., causal vs motivating 'reasons'.)

    Incidentally: a reader emailed me to report that reflexive actions are directly triggered by nerve pathways prior to the signal reaching the brain. So I probably should have used a different example of putative mental causation. But it goes to show how easily we may confuse causation with constant conjunction, suggesting additional reasons for caution about placing too much weight on apparently anti-epiphenomenal intuitions. (Though I should stress that this is a quite different argument from my one, which instead questioned whether our ordinary intuitions really are so anti-epiphenomenal in the first place.)

  8. Here's how I see the lay of the land at this point. Set aside what the folk might mean by "because" (you're right, it's probably multifarious). You would like to distinguish between strong causation and weak causation. And you would like it to turn out that things that supervene on strong causes are weak causes, while things that are merely correlated with strong causes are not weak causes. If so, there must be a difference between supervenience and mere correlation that confers weak causal status. You haven't said what it could be.

    It seems to me that an initially promising reply on your behalf is to appeal to counterfactual dependence. You might say that there is (typically) counterfactual dependence between the supervening properties and the effects but not between the correlated properties and the effects. That is, it might be true that had I not been in pain, I wouldn't have flinched; but false that had the barometer read differently, the storm would not have occurred. But then the challenge is to specify the sense in which this is a form of epiphenomenalism—what is this "oomph" that low-level dependencies possess and high-level dependencies lack? Put differently: why not think it's just weak causation all the way down?

  9. Strong ('oomphy') causation may be a bedrock concept: I feel like I have a firm enough grasp of the concept (at least assuming a simplified "billiard balls" conception of physics), though I doubt I could define it in other terms.

    One symptom, perhaps, is the following asymmetry: if we could change my qualia whilst holding the physical facts fixed, this difference would (contra interactionist dualists) have no effect on my subsequent behaviour. But if we changed my brain states whilst (magically) holding fixed my qualia, this could change my behaviour. So there's an important sense in which my behaviour is more causally beholden to my brain states than to my qualia.

  10. Note however that if qualia metaphysically supervene on the physical facts, then the first counterfactual is vacuous.

  11. Right, I think they only nomologically supervene (as revealed by the possibility of zombies, inverted qualia, etc.).

  12. Hey Richard,

    I wonder if you could elaborate - briefly - on what you mean by changes in brain states "could change my behavior." Perhaps you could also comment - briefly again - on the relationship between moral causes and brain/physical causes, as theorized by motivational internalists.


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