“It’s only when you start asking “what effect do my feelings have on my protons and neutrons?” that you start getting syntax errors.” – Disagree. “Feelings” cause measurable changes in body chemistry, and “feelings” can be altered by conscious choice; otherwise, biofeedback wouldn’t work. Reference the idea of “mind-body integration” as taught by yoga.

“Certain Game of Life configurations create patterns. The most famous is the glider, a pattern of on and off cells that moves diagonally across the grid. It is possible to implement an arbitrary Turing machine by arranging Game of Life patterns. Computability theory applies to such Turing machines. Thus while not eluding the Game of Life rules, new laws (computability theory) that are independent of the Game of Life rules apply at the Turing machine level of abstraction — just as Schrödinger said.

“Furthermore, conclusions about Turing machines apply to the Game of Life itself. Because the halting problem is unsolvable, it is unsolvable whether an arbitrary Game of Life configuration will reach a stable state.

“Not only are there independent higher level laws, those laws have implications for the fundamental elements of the Game of Life. I call this downward entailment, a scientifically acceptable alternative to downward causation.”

– Russ Abbott, “Reductionism, emergence, and levels of abstractions”
http://arxiv.org/ftp/arxiv/papers/0707/0707.4198.pdf

“In principle, that might be hard to arrange, if (for example) the decision of which team went to bat first had to be made by observing the behavior of a particle accelerator! So I guess it’s important for this thought experiment that baseball has no such rule.”

Can’t disagree — that would be a lousy rule. I was thinking more along the lines that it sure would be hard to specify the physical substrate in such a way as to result in Abner Doubleday (or Alexander Cartwright, depending on your preference) deciding that the base paths would be an oval rather than diamond — it would cut down on infield hits and stolen bases by a large measure and it would certainly be much harder to score from first on a double. Unless, of course, those changes also led him to shorten the distance between bases by some “corresponding” length.

Could we have such a thing as a “perfect” high-level theory?

Awesome question! As I see it, if we have a theory that describes (say) the behavior of some computer program, then not only is that theory not necessarily “approximate” by virtue of computers being complicated, composite objects; it might well be more accurate than our theory of the subatomic particles that the computer is made of! Of course a meteorite could always hit a computer and make it stop working. But crucially, most people wouldn’t call that a defect in a theory about computer programs—they’d just say that the (broken) computer is now a system to which the theory no longer applies.

@Mike:

with respect to the above quote, aren’t you just assuming that a particular change to the physical substrate ultimately has no impact on the game? At least in theory, particular changes (or a complex of changes) could “change” the game, couldn’t they?

You’re right: in this sort of Kripkean thought experiment, the ground rule is that we assume no changes to the observable, macroscopic features of the game. In principle, that might be hard to arrange, if (for example) the decision of which team went to bat first had to be made by observing the behavior of a particle accelerator! So I guess it’s important for this thought experiment that baseball has no such rule.

“I’d go maybe just a hair further: not only is a baseball game as real as the subatomic particles involved in it, but if we “swapped out” the subatomic particles and replaced them by a different physical substrate, it would still be the same game!”

I agree with the point of your posts, but with respect to the above quote, aren’t you just assuming that a particular change to the physical substrate ultimately has no impact on the game? At least in theory, particular changes (or a complex of changes) could “change” the game, couldn’t they?

Of course, as far as we know in most all cases it would be impossible to compute and predict what such changes would consist of, but in a sense that just reinforces the conclusion that higher level explanations do have a certain autonomy.

Initially I thought not, but actually I think there are such things.

Any logical tautology with a well-defined mapping from predicates (etc) onto properties of physical reality would count.

To the extent that high-level theories are imperfect, the imperfection hides in the details of the mapping.

So you could make a perfect high-level-theory by choosing an artificially simple mapping, e.g. if you have five objects and then create another three, you have eight. For suitably strict definitions of “object”, you now have a perfect high-level theory.

Does this help a believer in causally efficacious free will? Perhaps if you are prepared to say that a law of mathematics or computing causes effects in any physical system which satisfies its axioms… …you could argue that there is some program which constitutes your decision algorithm with the property that your brain is an instantiation of it. But I don’t think that the free will supporter would really want to think of herself as a program any more than she would want to think of herself as a collection of atoms. Certainly, it is an interesting train of thought, and from my reading of Dennett, Gary Drescher, Drew McDerrmot, etc it’s basically the route that some modern determinists/reductionists go down anyway. And I guess it answers the original question: is there downward causation? Well to the extent that you think that mathematics can cause things, there is.
Personally I like my cause and effect to be between concrete objects like electrons.

Since (like essentially all reductionism-debates among sensible people ) this one just boils down to the meanings of words, let’s define “super-reductionism” to be the following theory:

Higher-level phenomena ARE just aggregates of lower-level phenomena. In other words, not only are they causally determined by lower-level phenomena, but they can’t even be properly defined without reference to the lower levels.

My point was just that, if someone was tempted to believe super-reductionism—or if they thought that super-reductionism was the inevitable consequence of ordinary reductionism—then they could be cured by thinking about decoupling phenomena. Of course, this fits in perfectly well with what you said yourself:

just because we can think of something macroscopic in terms of its microscopic parts, doesn’t mean that macroscopic thing becomes any less real. Baseball is real, temperature is real, free will is real — all in the sense that they are useful categories for organizing the macroscopic world, whether or not these concepts are nowhere to be found in the vocabulary of fundamental physics.

I’d go maybe just a hair further: not only is a baseball game as real as the subatomic particles involved in it, but if we “swapped out” the subatomic particles and replaced them by a different physical substrate, it would still be the same game!

In particle physics, this feature is not only true but obvious and occasionally frustrating. It’s a consequence of the renormalization group; no matter what happens at high energies, low energy physics can be essentially unchanged. (We say that high-energy particles “decouple” from the low-energy phenomena.) That makes us sad, because we can’t simply do arbitrarily precise experiments at low energies to discover new massive particles; we have to build giant particle accelerators that actually reach high energies, and that costs money.

There is a slightly different flavor to things when you move to more slippery realms like computer programs or for that matter texts like blog posts. (I was addressing this a bit in comment #2.) It’s certainly true that very different substrates can represent the same higher-level processes. I think that’s an extremely interesting feature of the world, but don’t necessarily see that it counts as an “anti-reductionist” argument.

“It’s only when you start asking ‘what effect do my feelings have on my protons and neutrons?’ that you start getting syntax errors.”

Quite right. And it applies at the level of the neural correlates of feelings (a subset of conscious phenomenal experience) as well: there’s no accepted theory about how the correlates entail feelings, or how feelings could have an effect on their correlates. And it’s difficult to identify one with the other, since after all the correlates are in the public domain, feelings in the private (no one has ever observed a pain or any other conscious experience in the way we observe their neural correlates). So when you say “You are allowed to treat mental phenomena (or whatever) as perfectly ‘real’ and causally efficacious,” it might still be a mistake to suppose that phenomenal experience can play a causal role in neuroscientific or otherwise physicalist explanations of behavior. Rather you’ve got two parallel explanatory tracks, one physicalist and one experiential, and they are mutually irreducible even though highly correlated, http://www.naturalism.org/privacy.htm This solves, or perhaps dissolves, the problem of mental causation when it comes to things like feelings.

“This parallelism view gets strong support from dualities in physics. One thing we’ve learned is that you can have completely different descriptions of exactly the same underlying “reality,” but it’s not that one is lower-level and the other is higher-level; they’re simply different.”

Different, yes, but regarding the above: The phenomenal and physical aren’t different descriptions of a single underlying reality, but (I speculate) *constitute* two parallel “realities” generated by two epistemic perspectives, a subjective phenomenal reality of qualitative conscious states entailed (somehow – the hard problem of consciousness) by being an individual cognizer modeling the world, and a physical reality of non-qualitative concepts and theories generated by the intersubjective project of science modeling the world, http://www.naturalism.org/appearance.htm#part1

The nexus between brain-physics and high-level functions is an informational transpondence. To understand how it works you need to know all the codes involved. Talk to the fermion.

My favorite example of this come from David Deutsch:

“There are explanations at every level of hierarchy. Many of them are autonomous, referring only to concepts at that particular level (for instance, ‘the bear ate the honey because it was hungry’). Many involve deductions in the opposite direction to that of reductive explanation. That is, they explain things not by analyzing them into smaller, simpler things but by regarding them as components of larger, more complex things– about which we nevertheless have explanatory theories. For example, consider one particular copper atom at the tip of the nose of the statue of Sir Winston Churchill that stands in Parliament Square in London. Let me try to explain why that copper atom is there. It is because Churchill served as prime minister in the House of Commons nearby; and because his ideas and leadership contributed to the Allied victory in the Second World War; and because it is customary to honor such people by putting up statues of them;
and because bronze, a traditional material for such statues, contains copper, and so on. Thus we explain a low-level physical observation– the presence of a copper atom at a particular location– through extremely high-level theories about emergent phenomena such as ideas, leadership, war and tradition.

Presumably a reductive ‘theory of everything’ would in principle make a low-level prediction of the probability that such a statue will exist, given the condition of (say) the solar system at some earlier date. It would also in principle describe how the statue probably got there. But such descriptions and predictions (wildly infeasible, of course) would explain nothing. They would merely describe the trajectory that each copper atom followed from the copper mine, through the smelter and the sculptor’s studio, and so on. They could also state how those trajectories were influenced by forces exerted on surrounding atoms, such as those compromising the miners’ and the sculptor’s bodies, and so predict the existence and shape of the statue. In fact such a prediction would have to refer to atoms all over the planet, engaged in the complex motion we call the Second World War, among other things. But even if you had the superhuman capacity to follow such lengthy predictions of the copper atom’s being there, you would still not be able to say, ‘Ah yes, now I understand why it is there.’ You would merely know that its arrival there in that way was inevitable (or likely, or whatever), given all the atoms’ initial configurations and the laws of physics. If you wanted to understand why, you would still have no option but to take a
further step. You would have to inquire into what it is about that configuration of atoms, and those trajectories, that gave them the propensity to deposit a copper atom at this location. Pursuing this inquiry would be a creative task, as discovering new explanations always is. You would have to discover that certain atomic configurations support emergent phenomena such as leadership and war, which are related to one another by high-level explanatory theories. Only when you knew those theories could you understand fully why that copper atom is where it is.”

You may be confusing two different kinds of “autonomy”

I was careful to say a “sort of” autonomy, since I know there’s also an obvious sense in which evolution can’t be autonomous! (Namely, once you’ve fixed all the facts about the laws of physics and the initial/boundary conditions, you’ve also fixed the observable higher-level behavior, at least probabilistically. That’s true essentially by definition: if there were some other determinant of the higher-level behavior, we’d simply add it to our description of physics!)

in any specific instance of evolution, if evolutionary theory predicts X and physics predicts Y, Y will happen

Not so fast: if our theories of evolution and physics were both “perfect”, then clearly their predictions would never disagree! (In particular, a “perfect evolutionary theory” would need to take as input every possible contribution to fitness, which certainly includes DNA-level contributions.)

If, on the other hand, both theories were imperfect, then it’s of course possible that the evolutionist would predict X, the physicist would predict Y, and X would be right (the usual example being Lord Kelvin’s despite with biologists about the age of the sun). So maybe what you really mean is that we can imagine a “perfect” theory of fundamental physics, but not a similarly “perfect” theory of evolution?

Hofstadter’s proposition takes your parallel equivalence a step further. He also names the trade off, although not as rigorously as some would like: Moving “Up” hierarchical levels sacrifices some informational resolution, but increases comprehensibility. He, like you, contends that descriptions at either the level of physics or the level of percepts. I really like that you noted that the “higher level” must be a fully autonomous causal system – another way of framing this self-consistency may be to say that the noise in the lower levels is insufficient to affect causal relationships at the higher level.

What’s particularly interesting to me is the relationship between levels of physical reality and “conceptual reality”, if we are to take the mind as a real thing. Hofstadter has a lot to say about this in terms of the emergence from “level crossing” feedback loops, and draws an analogy to the Godel incompleteness theorems, which is sort of a favorite stone to throw at reductionists (Penrose hurls it, as well, in “The Emperor’s New Mind”).

Myself, I don’t think such arguments about level crossing are all that interesting. What is interesting is the structure of information flows at the physical level, and how it relates to the information geometry of the mind. These types of correlations are what are ultimately useful to those with the engineering ambition to build (and therefore understand) minds that include the features of the human mind. The computer example is a very good one, and I’d recommend Charles Petzold’s “Code” for anyone wanting to explore that particular example in excruciating detail.

You may be confusing two different kinds of “autonomy”; evolution is “autonomous” from physics in a broad sense: if you have a multiverse of universes, each with different physics, many of them will have evolution. But evolution is not autonomous from physics in detail: in any specific instance of evolution, if evolutionary theory predicts X and physics predicts Y, Y will happen. (For example, an otherwise highly fit genotype could by pure chance cause the DNA molecule which encodes it to become unstable, so fitness would fail to increase as you might predict if your theory didn’t talk about DNA)

@Bee, do you mean that Sean’s argument about the number of equations and unknowns is wobbly or only appears wobbly? I certainly appreciate that it could appear wobbly to the semi-initiated, those familiar enough with infinities to see that there could be a problem but not sufficiently familiar the fact that well-posedness can be still be established in many infinite dimensional systems of equations relevant to physics, once reasonable constraints are imposed on potential solutions (continuity, etc.).

An interesting spin on this is James P. Hogan’s book Code of the Life-Maker; highly recommended. (For the record: I grew up on Asimov (whom I met personally once) and Clarke and could never really get into most other s.f. (I was not impressed by, say, Heinlein’s Stranger in a Strange Land (though it is a great title). Some of Hogan’s books are quite good, some are OK. There are probably some which I haven’t read which aren’t good at all. (Of course, we all know that Wagner’s music is better than it sounds and one should, at least in some circumstances, distinguish between the artist and the art. In particular, anyone who finds Hogan rather unpalatable as a result of relatively recent public statements can rest assured that there is no hint of this in his books, at least in the earlier ones (which I have read).) I am not ruling out the fact, though, that there might be other s.f. writers, young or old, who are worth reading for me.)