Downward Causation | Evolving Thoughts by John S. Wilkins

The final claim for there being an ontological sense to emergence is “downward causation“, a phrase coined by the evolutionary epistemologist Donald Campbell in the 1970s. The idea here is that emergence is real because higher-level (or bigger, composite) entities cause changes in the properties and dynamics of their parts. This is very big in the philosophy of mind. It is also often used by a certain kind of systems thinking in physics. Recently, Sean Carroll took it to task.

So what does the claim there is downwards causation consist of? A simple formulation is by Bernd-Olaf Küppers: “The whole determines the behaviour of its parts” (Küppers 1992:243). That is to say, the causal arrow points from larger or organised whole to part. We can diagram these:

Emergentism of this kind (there are several) is unlovely, philosophically, as it has way more causal arrows than are needed. Or does it? Our intuitions are that what happens at the higher level do in fact influence what happens at the lower, and so things like “temperature” causes molecules to move about more rapidly. I think what happens here is that an explanation moves downwards, but only because we have hypostatised (thing-ified) an abstract term. It’s very little more than definition. But causation, if it occurs at all, occurs at the “lowest”, which is to say, the physical, “level”.

The virtue of post-Baconian science is that final causes were abandoned, except (and this is often overlooked in the rhetorical flourishes of this old debate) where you have a system capable of projecting goals and seeking them. And these systems (which you may gather includes humans) also call for an explanation: how can systems seek goals? The answer is fairly simple. They do so because their ancestral systems did so, only perhaps less well. There is nothing special about these systems in an ontological sense – they are just composites of less complex systems, and have degrees of freedom that the parts don’t have.

But we obviously do have a choice (volition) even though we are determined. This is the standard compatibilist position. It’s silly to suppose that finding out that we’re deterministic systems would somehow mean that we’ve discovered that we don’t think.

I don’t know what Searle can mean by the term “consciousness” if it is non-reducible. How does he know what it is if it is not explicable and approachable by ordinary empirical means? It’s a meaningless term unless you break it down to simpler things like feedback loops of control systems.

Well, Searle talks about consciousness as being causally reducible, but not ontologically reducible. I’m not sure how that works exactly.

But the full system — in its microphysical characterization — will always have more degrees of freedom than does a composite system. The wheel can’t win the the Indy 500, but it’s a mistake to just consider a single part. You have to consider all the parts that compose the system. And then the relevant point is that the parts can always do more than the whole can. What makes something a “whole” is that you rule out certain behaviors of the parts and thereby reduce the number of degrees of freedom. So the parts (as a group) do have the degrees of freedom of the whole, and they have extra degrees of freedom as well.

Feedback is not a special kind of causation – just the ordinary kind that has a particular network topology. So it is not a counter-instance to my rabid reductionism, because all causation is still just physical. What happens at “higher” levels is still constituted by the component parts and their physical properties.