Recognising Top-Down Causation by George F. R. Ellis

Over on the Rationally Speaking blog, Massimo Pigliucci has an interesting posting: Essays on emergence, part I , including a link to a a very interesting paper by Robert Batterman.

An ensuing interaction with Sean Carroll includes the following post by Carroll:

"Sean CarrollOctober 11, 2012 4:46 PM

I don't know what it would mean to "derived physical reductionism," nor do I think that qualitatively new emergent behavior is absent from Newton's laws (depending on definitions). The point is simply that Newton's laws, applied to a set of particles, gives you a closed set of equations. With appropriate initial conditions, the solutions are unique. There is no room for additional causal influence. The equations give unique answers; you can't get a different answer without violating the equations.

There is an important and interesting discussion to be had about emergence, and it has nothing to do with being unable to predict behavior from component parts, nor with new "causal powers." "

Pigliuicci's response (October 12, 2012 8:25 AM) includes, "I find that argument wholly unconvincing. First, Newtonian laws are known to be approximations, so clearly there *is* room, in a sense. Second, those laws tell you precisely nothing about all sorts of complex systems, like the temperature of phase transitions of water, or the functioning of ecosystems, so to claim (global) causal closure seems strange."

He does not however make the points I make in Part 6 of my essay, including particularly the point I make in my posting here on Sep. 17, 2012 @ 18:15 GMT:

" The mechanism of superconductivity cannot be derived in a purely bottom up way, as emphasized by Nobel Prize winner Bob Laughlin; see the Appendix to my essay for Laughlin's statement in this regard. The reason is that existence of the Cooper pairs necessary for superconductivity is contingent on the nature of the ion lattice, which is at a higher level of description than that of the pairs; they would not exist without this emergent structure."

These arguments, it seems to me, completely undermine Sean's billiard ball point of view, based in Newtonian physics. They provide good reasons that top down causation can take place in computers and the brain without contradicting the underlying physics. And that is why the existence of computers such as the one you are using at this moment is possible, without invoking magic. It is the result of top down causation from the human mind into the physical world.

George

Tom,

thanks for all that. I'll have to take time to digest it - I'm travelling at the moment (will be in Boston Sunday evening to Tuesday afternoon before flying home via New York) and have to do other stuff.

But yes Bar Yam seems really interesting: much deeper than Per Bak, who tries to construct stuff in a purely bottom up way. There's a strict ceiling to what that can achieve. Sand piles, bird flocks, reaction-diffusion patterns, etc. are a step on the way but they are not the real thing.

George

Hi Ben

I think that is an exciting possibility to pursue. Please note that it might relate also to my posting of Oct. 2, 2012 @ 07:24 GMT. I am a fan of Causal Set Theory, and trying to develop it the way you suggest would be a great project.

Maybe there is a Wheeler-like dictum here: "Part from whole!"

George

I've contributed the following further comment over there:

Sure the lattice emerges according to well defined bottom up principles. Once this has happened, it then exists as an entity at a higher level of scale than the particles out of which it is composed (you have to use quite different variables to describe this lattice structure than you do to describe the particles: these variables are not reducible to lower level variables). The key point is that until it has so emerged, no Cooper pairs are possible. Once it has emerged, they can come into existence. Thus it is the very existence of the higher level structure (the lattice) that enables the lower level constituent entities (the Cooper pairs) to come into being.

Sure you can work out in a bottom up way what effects the Cooper pairs mediate. But they can't act in a bottom-up way to create any physical effects at all until they exist - and their existence is contingent on the detailed nature of the higher level structure. That's a clear case of the causal effects of context on lower levels - that is, by any reasonable definition, causation flowing downwards in the hierarchy of structure. But if you dislike the word "causation", just call it a contextual effect,

It is because superconductivity depends on this mechanism that you can't derive it in a purely bottom up way. This is stated strongly by Laughlin in his Nobel Prize lecture as follows:

"One of my favourite times in the academic year occurs in early spring when I give my class of extremely bright graduate students, who have mastered quantum mechanics but are otherwise unsuspecting and innocent, a take-home exam in which they are asked to deduce superfluidity from first principles. There is no doubt a very special place in hell being reserved for me at this very moment for this mean trick, for the task is impossible. Superfluidity, like the fractional Hall effect, is an emergent phenomenon - a low-energy collective effect of huge numbers of particles that cannot be deduced from the microscopic equations of motion in a rigorous way, and that disappears completely when the system is taken apart ... The students feel betrayed and hurt by this experience because they have been trained to think in reductionist terms and thus to believe that everything that is not amenable to such thinking is unimportant. But nature is much more heartless than I am, and those students who stay in physics long enough to seriously confront the experimental record eventually come to understand that the reductionist idea is wrong a great deal of the time, and perhaps always... The world is full of things for which one's understanding, i.e. one's ability to predict what will happen in an experiment, is degraded by taking the system apart, including most delightfully the standard model of elementary particles itself."

[R B Laughlin (1999): `Fractional Quantisation'. Reviews of Modern Physics 71: 863-874]

The same basic effect - lower level entities only exist by courtesy of the detailed nature of the higher level structure - occurs all over the place in biology, for example in symbiosis, in ecosystems, and in the case of say blood cells in the human body.

George

If you want to understand what physics is about, you should read a basic textbook on the subject. I suggest Conceptual Physics by Paul Hewitt. The chapter headings will give you an idea what basic physics covers:

1. Mechanics; 2. Properties of matter; 3. Heat; 4. Sound; 5: Electricity and magnetism; 6. Light; 7. Atomic and nuclear physics; 8. Relativity.

A more advanced text would include chapters on statistical physics and quantum physics, as well as topics such as plasma physics. Specialised texts will deal with biophysics, which is relevant to vision, but it is a very small part of physics.

In response to a post by Peter Bokulich over on Massimo's blog (see my post here of Oct. 13, 2012 @ 08:53 GMT), I've now posted the following response:

Hi Peter,

I appreciate your approach. The key issue for me is that you agree that there are real high-level causes. Good. I agree that given the lower level dispositions of states resulting from those higher causes, the lower level physics gives a complete causal account; but overall, the causal account is incomplete without taking into account the way higher level causes lead to those specific lower level dispositions. A good example is a digital computer, where an engineering computation is taking place because a) C++ has been loaded as the current high level software, b) simulation software incorporating the relevant finite element algorithms has also been loaded, and c) specific initial data to run the relevant algorithms has been entered via the keyboard. The outcome that occurs is then a unique result of the lower level electronic states resulting from a), b) and c). However there is no way that the numerical algorithms embodied in the patterns of lower level excited states can be derived in a purely bottom up way from the underlying physics. It's a category error to assume that purely physical processes can lead to existence of any such algorithms.

Whether we agree on causation or not depends on the weight you put on the words "nothing but" in the phrase "are nothing but constrained, structured, microphysical causal features". I think the explanation above says it's a mistake to use the phrase "nothing but", because significant other causal effects are at work. Part of the problem for a true reductionist is that the electronic gate states are "nothing but" specific states of quarks and electrons; and these again are "nothing but" excitations of superstrings - if they exist, which may or may not be the case. Which level are you claiming is the true microphysical level? The embarrassment for a true reductionist is that we don't know what the lowest level structure is - we don't have any viable theory for the bottom-most physical states. Thus if we take your phrase at face value, all physics is "nothing but" we know not what. Why not leave those words out?

As to quantum indeterminism: it plays two significant roles. Firstly, it ensures that outcomes on Earth today cannot have been uniquely determined by initial conditions in the early universe, inter alia because cosmic rays have altered our genetic history significantly, and emission of a cosmic ray photon is (assuming we believe standard quantum physics) an inherently indeterminate process. The complex structures that exist have come into existence through emergent processes with their own logic that is independent of the underlying physics. Secondly, the most important such process is adaptive selection, which is guided by selection effects operating in a specific ecological context; and that is an inherently top-down process (see "Natural Selection and Multi-Level Causation" by Martínez and Moya in Volume 3 (2011) of Philosophy and Theory in Biology, available from Massimo's website). In the example just given, quantum uncertainty plays a key role in providing the repertoire of variant states on which adaptive selection can operate (without the cosmic rays, there would have been fewer such states to choose from). The conjecture is that perhaps something similar might be true in the way the brain works. But that's very hypothetical.

Hi Stefan

Thanks for that. Well the deep issue you raise is, "Is the universe causally closed?" My answer is, if you mean only the physical universe, the answer is no! Ok hackles are rising and squeals of protest fill the air, but please hear me out.

This depends on issues of ontology: What kinds of thing exist? I addressed this in my paper True Complexity and its Associated Ontology. As in my essay, I define something as existing if it either (i) is a material entity, or (ii) has an undeniable causal effect on material entities. You'll find various non-physical examples there, but the key one for present purposes is:

Mathematics and logic: A Platonic world of (abstract) realities that are discovered by human investigation but are independent of human existence. They are not embodied in physical form, but can have causal effects in the physical world.

Roger Penrose [The Large, The Small, and the Human Mind], Alain Connes, and many others have argued for such a Platonic world of mathematics, which is not invented but humans - its nature is discovered by them (e.g. we did not wish to discover that the square root of 2 is irrational: we were forced to acknowledge that this is a mathematical fact through a process of logical investigation). How does it have a causal influence in the physical world? Through the human mind, which uses calculus and facts such as the value of pi as the basis for engineering calculations.

The relevance to my previous post is that there is also space of all possible logical algorithms out there, waiting to be discovered. This is the ultimate source of computer algorithms. They become causally effective once discovered and implemented, but their existence is independent of such discovery. They are independent of time and place and culture, and (like mathematical truths) can be discovered by any intelligent beings anywhere in the universe. Thus for example there is a finite number of ways to sort a column of letters or numbers into ascending order. Any algorithm you may employ for this purpose will necessarily be one of this finite set of algorithms (e.g. Quicksort). They have causal power in terms of events in the physical world, because they lead to printouts of sorted numbers (which cannot exist if one does not employ one of these algorithms).

So the world of material entities is not causally closed: it can be causally affected by abstract entities, such as algorithms, which underlie all computer operation. This is an existence proof for causally effective non-physical entities. There are other kinds of such entities , e.g. human plans for building a Jumbo jet airliner. My paper cited above discusses them.

George

Hi John

yes I agree with you about physics - and will be pursuing this. I'm just reading Robert Rosen's very deep book "Life Itself" which argues that causation is much wider than usually considered in physics - indeed that reductionist physics is a special case of the much wider kind of causation that operates in the real universe.

He also looks at the case of mathematics and how it fits in. You might enjoy this book.

Just one point: I avoid the word "infinite" in this context. This is needed as a mathematical concept, but does not occur in physical reality (Hilbert). No real causal system is infinite.

George