Dear Eric
>> I think our key difference is how seriously we take what Jaegwon Kim called "the exclusion argument." If some higher level supervenes on some microphysical level, and the future of the system can be described entirely in terms of the dynamics of this underlying microphysical level, then what extra causal work is the higher level doing? If it's not doing any, then the higher level should be excluded (considered epiphenomenal, i.e., it doesn't matter or do anything). Figuring out a way out this trap is the fun of trying to come up with an actually viable theory of emergence.
OK: nicely stated
>> The specific connections and excitations of the brain supervene on the underlying microphysical state of the brain. Thus, any action of the brain (like recalling or arguing) can be described entirely in microphysical terms. So what work, exactly, are these connections and excitations doing? The exclusion argument applies.
The physical aspects of what is happening can be so described. The logical aspects cannot. They are a different (simultaneously occurring) level of causation.
> If supervenience applies at each instant, then of course it also applied when those patterns were unfolding over time. The patterns supervened on some underlying microphysical states. So why didn't those microphysical dynamics do all the causal work over that time? Even historically, the exclusion argument applies.
Because they don't describe all the causal influences at work, they only describe the physical level. Some of the causal influences are abstract: the power of money is an example, as is the causal power of a theory such as Maxwell's equations, which led to existence of radio and iphones.
> Just because the underlying physics has no concepts doesn't mean it can't do all the causal work that underlies concepts.
It does causal work at its level. That's not all the causal work taking place. Logical causal work is underway as well as flows of electrons.
>> And again, as just pointed out above, a historical process of development doesn't allow one to get out of the exclusion argument. As I first asked above: how can the underlying physics enable but not determine a supervening level? The lower level determining the higher level at any given instant is what supervenience means.
You have to trace where did those causal ideas come from. They came from a process of adaptive selection which led to logical rejection of some ideas and acceptance of others. It is that *logical* process that is driving what is happening and leading to outcomes like existence of iphones. The key point here is that the lower level is what it is because it has been adapted to those higher level logics over time. Given that that adaptation has taken place over time, then supervenience can in principle tell you what will happen next at an instant.
>> "...the randomness of the lower levels enables higher levels to select what outcomes at the lower levels are suitable for higher level purposes, for example by selecting outcomes of gene regulatory networks by setting operating conditions for those networks. "
> Unfortunately, those operating conditions themselves supervene. There are some microphysical correlates to whatever thing is selecting outcomes. Why not just say those microphysical correlates are doing the selecting? The exclusion argument applies.
Because that is only part of the interaction network that is taking place. It is the higher level arrangement of those lower level states that is the key thing. Those higher level arrangements cannot be described in terms purely of lower level variables, because they are by definition at a higher level of organisation
>> As for Crick, I agree he clearly believes higher levels like neurons actually *do* things. Most people believe this. It's just that no one knows quite how.
Worse than that: if you try to follow it down there is no known theory of the lowest level, we don't know if its superstrings, some kind of grand unified theory, some form of loop quantum theory of spacetime. If you can't say *on what* higher levels supervene, your theory is nugatory. It explains nothing. And you are also dodging the fact that those lower levels are NOT deterministic, so at their own levels the outcomes are never determined by the initial data. So their effect on higher levels is also not determined.
>> In my view, the only way to answer these questions is to figure out what a supervening higher level can do causally *above and beyond* its underlying microscale: i.e., causal emergence. This beats the exclusion argument because the higher level is doing more causal work than can be accounted for at just the lower level (even as the higher level supervenes).
Well I agree on that. Essentially that is what I have been trying to describe above, perhaps not successfully enough. The mental level does mental work, which is causal work not accounted for at the micro levels. The electron level accounts only for the movement of electrons, if we stop going down at that level - which is illegitimate as it is not the lowest level, as just mentioned.
It would be good if we could agree on exactly how to cash this out. Maybe we can discuss when I am in New York for the World Science Festival.
regards
george
