Of Downward Causation and Hipsterism

I doubted that I would ever tell this little story in a serious academic context, until a version of it came tumbling out of me in my recent specialist exam. Now that I’ve already suffered the embarrassment of having my committee hear it, I may as well share it with the wider world.

As a bit of background, consider the question of downward causation. Some philosophers (Evan Thompson, R.C. Bishop, Alicia Juarrero) have been arguing that complex systems exhibit downward causation, where the system as a whole constrains or explains the behaviour of its parts. We can’t just look to the intrinsic properties of the parts to understand the overall dynamics, we have to also include their organization as a whole system.

The example I like best is Raleigh-Benard convection, this thing:

So imagine this is water (or some other fluid) and the bottom plate is heated. Above a certain temperature, the water will make these lovely little rolls that form hexagonal cells. That’s Raleigh-Benard convection.

And the argument is that before convection starts, the individual water molecules are just bopping around, doing their own thing. The relevant causes are just the low-level microphysics of the system. But once a convective regime takes hold, the story goes, we need to consider another kind of cause – the constraint put on elements of the system by the organization of the system as a whole. So because the whole system is spiralling, individual molecules can’t just bounce around in any old direction, their set of possibilities is constrained to just rolling action. And that’s downward causation – a kind of systemic constrain on the possibilities of the parts.

I’d like to propose that we look at that same story from a different perspective. Suppose we ask what it would be like to be one of those water molecules. I think that if you look at it from the water molecule’s point of view, it’s pretty clear that whatever these systemic constraints that convection introduces are, they aren’t ‘downward’. They may tell us something about the system as a whole, but they don’t really tell us anything about the parts of the system, and don’t constitute a real constraint on the behaviour of those parts.

To that end, I’m pleased to introduce to Walter the Water Molecule:

The life of a water molecule is a simple but satisfying one. The really nice thing is that, unlike people, water molecules always act perfectly authentically, according to their own Innate Physics. When bounced by something from the left, Walter zooms right..

When something bounces him from the right, Walter always reacts in exactly the way he pleases, bouncing away to the left.

And no matter what his circumstances, Walter would always remain true to his own Innate Physics.

But one particularly hot day, Walter noticed something funny. Despite his doing nothing different than what he always had, it seemed more and more that everyone else was doing exactly what he was doing. He had decided, on account of his Innate Physics, to do vertical loops that day, but for some reason everyone else was doing it as well!

Since he was doing what he had always done, and now everyone else was doing the same, there was only one conclusion that poor Walter could come to: they were all copying him! Walter therefore became an insufferable hipster.

The moral of the story is, don’t be like Walter. His confusion was to think that just because everyone is doing the same thing, they must be following the crowd somehow. He assumed that if the overall behaviour is orderly, that must mean that the individuals involved must somehow be constrained from following their own Innate Physics. But that’s just not true. Water molecules do their own thing, no more and no less, both before and after the onset of convection.

Of course, something does change when the system changes from being disorderly to the orderliness of convection. What I’m rhetorically gesturing at here is that what changes isn’t anything about the parts of the system – they keep on keeping on in exactly the same way no matter what. What changes is at the system level. So there isn’t any good sense in which this self-organized behaviour counts as ‘downward’ causation.


4 thoughts on “Of Downward Causation and Hipsterism

  1. Cory this example of yours has always fascinated me. I would like to ask some clarification questions, because as I read it here, it seems like you and the downward causationists might be talking past each other.

    You claim that the downward causationists say that in examples like Raleigh-Benard convection, the system as a whole constrains or explains the parts. You argue that this is fundamentally confused, that the downward causationists improperly infer from overall orderly behavior that the “innate physics” of the parts is somehow constrained. For you, the parts are always following their own innate physics – nothing has changed about their actions. So there is no real notion of causation that holds from the whole to the parts.

    What does it mean to be “constrained from following their own innate physics”? And would the downward causationist agree that some kind of violation needs to take place in order for downward causation to hold?

    One reading of “constrained from following the innate physics” is that the physical laws that hold at the micro level are broken (or excepted) when certain marco level configurations hold. Such a claim seems bold and far fetched: if we think there are laws at work at all, we don’t think that they are broken by the orderly nature of the system as a whole.

    I wonder if being constrained is needed to make the point of the downward causationist? I might see a reading that provides more room for the complete system in the story of Walter while maintaining his innate physics. You see, Walter could follow his preferred way of bouncing at all times. But what determine’s Walter’s preferred ways of bouncing are a combination of his situation and his innate physics. One could not explain Walter’s motions just by appealing to his innate physics, one would need to appeal to the innate physics as well as his situation (for example, where he was hit by his friend Wendal). In RBC, that situation is a highly organized system. Walter doesn’t do anything other than what he wants to do according to his innate physics in RBC, but what he wants to do is determined by the context of RBC. In this sense, we do seem to be able to use the organization of the system to explain Walter’s actions: Walter acts as he does because of RBC as well as his innate physics. Walter is mad everyone is copying him, but he can’t become a hipster – at least, not with his innate physics and RBC! This doesn’t seem so far fetched, but might be weaker than the downward causationists have in mind.

    The above re-reading of Walter only focuses on explanation. Given the way you’ve described the story of Walter, it does seem odd to claim that Walter has been “constrained by” RBC, after all, even my retelling has him doing exactly what he wants. I wonder however, how much of this is because Walter is described as always acting authentically (which in your example, seems to indicate that he is acting deterministicly)?

    Wouldn’t the downward causation describe RBC in terms of statistical thermodynamics? In that case, I can see what the real meaning of “constraining” might be for the downward causationist: Walters actions will be described in some kind of probability function, and when RBC arises, that probability function will change drastically, becoming much more certain around specific values. His innate physics allows for this, but it doesn’t explain why it happens when it does, in order to explain that, one needs to appeal to RBC.

    I’m not sure if what I’ve said above the downward causationist would agree with. Can you set me straight?

    • You’ve got the dialectic right, or at least you’re presenting the sophisticated version of downward causation that I’m trying to resist. Some people do want to say that downward causation involves actual violations of micro-physical law, but not the people I mentioned. When they talk about ‘constraints’, they mean some reduction in the degrees of freedom of the system. So the reasoning goes that because water molecules can go any which way in the conductive regime, but only make loops in the convective regime, their behaviour is more constrained under convection. So nothing forbidden by physical laws goes on, but some things that would be allowed do not happen. It’s a reasonably plausible view, I just think it’s wrong.

      It’s right of course to say that Walter’s behaviour isn’t just a product of his own innate physics, that it also involves his situation. But that is presumably true for any molecules under any circumstances. Something was supposed to have changed when the convection started, a new cause (of a sort) coming into play. But there were always things around to bump off of, so just saying that we need to include his situation doesn’t seem to be enough.

      In the end, you seem to be coming around to a view very similar to my own. I think that the overall statistics of the system change when convection starts, so there is something like a system-level cause going on. The only part I want to disagree with the downward causationists about is that that system-level change entails anything about the parts of the system. I’m of the opinion that statistics can explain a distribution (a system level fact) but not any of the instances of that distribution.

  2. Top-down causation is the whole constraining the parts. It not non-physical, here the Benard cell constrains the degree of freedom of the individual molecules (its a new level of self organization, not any non-conformist order of hipsters). There is no violation of Physics, the concept of DC merely suggests macro level constraining the micro level. The notions of constitution and constraint, which are both forms of non-causal determination, make causal relations crossing levels of composition conceivable (Max Kistler).

    • I’m not sure this is coherent. Can you constrain something without touching it? Without imposing any physical force on it at all? If downward causation is non-physical as you say, how does it impose constraints on anything whatsoever?

      A constraint is when something is prevented from doing something it was going to do. But the molecules of water all do exactly what they were going to do anyway. No additional constraint is added on to their movements, except constraints that actually operate at the micro-level. So I don’t think you can meaningfully maintain that it is both a constraint, and non-physical. Either it’s physical, in which case it can constrain, or its not, in which case it can’t.

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