Sunday, October 24, 2010
I spotted this piece of street art whilst walking through Norwich. I photographed it because in a crude way it illustrates the nature of physical explanation as I understand it, particularly in physics. We’ve heard about the the “Turtles all the way down” scenario; here an infinite regress results as the demand to explain the explanation leads to a decked succession of objects that fail to converge on any final explanation that could be said to have some semblance of being a natural end point. In contrast my photograph is a way of conveying, using another rather woolly zoological metaphor, that explanation in physics does involve a progression of object that shows some kind of convergence: As is often remarked, physics succeeds in showing how the complex can be generated from the relatively simple and as physics advances the complexity of the cosmos is reduced to elementary explanatory objects. In my street art metaphor this reduction in complexity is expressed by the diminishing size of the supporting mammals, but as this is a rather loose metaphor a type violation is allowed and the final explanatory object is represented by a ball – something mathematically simple, elemental and above all irreducible. As I have affirmed many times in this blog, physics, in the final analysis, is a science of description that gets its explanatory purchase on nature simply because nature is presumably highly organized. This means that if the cosmos is a closed system and is appropriately organized it will be amenable to a succession of increasingly compressed descriptions. It is the destiny of physics, therefore, to eventually come up against a logical barrier beyond which it cannot proceed; for there comes a point when the explanatory “compression” can go no further; any further attempt to explain the explanation simply leads to the “turtles all the way down” effect. Thus, if physics is to lead us to a final theory it is destined to ultimately leave us at a barrier of incompressible brute fact. Having then arrived at this kernel of fact its job is finished. (If indeed such is possible – it may not be possible as nature could conceivably be mathematically open ended)
The news conveyed by my metaphor is worth putting beside the views of two people: Firstly Richard Johns, who is probably an intelligent design creationist and whose paper on the limits of Self Organisation was mentioned in my last blog entry. My second client is the uncompromising evangelical atheist Larry Moran.
Richard Johns: In his paper on self organization Johns arrives at a conclusion that for many ID theorists is the anti-evolution community’s shibboleth of authentic ID; namely, that there is some kind of conservation law of complexity and/or information that means you can’t have “ a free lunch of complexity”. According to this view the presence of complex organisms must have its origins in more or less equally as complex precursors. Using the zoological metaphor the anti-evolutionist’s view is that one type of elephant can only be supported on another type elephant; so, either you end up with “elephants all the way down” or you believe that at some point God created the first elephant. In other words anti-evolutionists are unlikely to favour the view expressed by my Norwich street art.
I have read Richard Johns paper on the limits of self organization and although I haven’t properly completed my analysis of it let me say in advance that am I not entirely happy that the conclusions of this paper are robust. I will, in due course be giving a detailed analysis of the paper, but suffice to say here that Johns’ reasoning does not take into account that a relatively small subset of complex forms can be generated by simple algorithms. Johns appears to have been mislead by the fact that the overwhelming majority of complex forms can only be reached algorithmically if either the algorithm is executed for a prohibitive amount of time or has available complex initial conditions on which to work. Johns’ reasoning certainly applies to the large majority of configurations and therefore it looks as though Johns has been too easily satisfied by the fact that in terms of probabilities his argument works: Because probabilities favour the situation where complexity arises only from complex initial conditions or after impractically long execution times, then probabilistically speaking Johns is right. But he then fails to take into account the rare cases where simplicity to complexity is possible. It is, presumably, well within the capability of a Divine intelligent designer to contrive one of these rare cases of simplicity to complexity in realistic execution times. Thus, given that Johns is a suspected ID creationist it is ironic that it is the very concept of a Divine designer that in the final analysis raises doubts over this line of argument as a way to ease through anti-Darwinian sentiments.
Larry Moran: In this post Larry responds to some questions posted on the Anti-Darwin web site “Evolution and News”. The first three questions impinge on the subject matter of this post and so I have reproduced these questions and Larry’s answers below. That in the final analysis physical explanation is destined to come up against a fundamental logical barrier is perhaps indicated by Larry’s responses: He looks a little bit like a baffled man who is shifting his weight from one foot to other.
1) Why is there anything?
I don't know and I don't really care. I'm quite happy to think that something has always existed but I'm not troubled by the fact that our space-time may just be an accident.
Well, I do care and I am more than a little curious about ultimate origins and do my best to think past the barrier of physics’ incompressible kernel of explanatory information. If this requires some nifty and reflexive philosophical footwork then so be it. Besides, a philosophical frame of mind probes the meaningfulness or otherwise of linguistic forms like “space-time may be just an accident”; it’s a frame of mind that doesn’t accept an appeal to randomness as a pretext to shelve the problem. For something to be an accident we have to embed it in some higher context in which the event can be judged as accidental; for example, throwing a six on a die is an “accident” within the higher context of the physical circumstances surrounding the throwing of the die. In follows then that “accidents” require some sort of physical context, and this of course raises questions about the origin of this context. The spectre of “Turtles all the way down” is haunting us once again.
So just what explanatory status does Larry’s “accident” have other than as a pretext for dismissing the problem with a bit of hand waving? Related to this particular form of hand waving is the common misconception that if space-time is some kind of inflated quantum vacuum fluctuation then the problem of something for nothing is solved: Somehow amidst this kind of reasoning questions about the problematical nature and origin of physical laws that can “create ex nihilo” in this way just get quietly dropped. In any case it is not at all clear to me that physical laws and the material substrate which they describe can be meaningfully separated. The notion that the laws of physics play the role once played by the “Word of God” by bringing things into existence suggests that Christian theology is deeply rooted in our culture and is subliminally present in the thinking of Westerners; even atheists.
2) What caused the Universe?
I don't know. In fact, I'm not even sure what you mean by "cause." I'm told by experts in the field of cosmology that there's no need to invoke a supernatural being to explain the origin of the universe but if you want to believe in a deist god then that's all right by me.
I agree with Larry’s view that the meaning of the word “cause” is nebulous: Understood in the very day to day “domino effect” sense of one thing interfering with another in a sequence of events is not very helpful when viewed in the light of physics whose most general explanatory structures are mathematical constraints rather than rules of how effects are transferred from one object to another. Larry’s passing on the question of “ultimate causes” to cosmology experts is OK, but we happen to know in advance about the logical limits of what cosmologists can ultimately achieve – namely, an elemental kernel of brute fact, the terminus of descriptive science. If physics ever reaches this point then we can say that physics has a complete theory, but only in a descriptive sense; for in a logical sense physics cannot avoid a final incompleteness.
What Larry seems not to have conceived is that any truly supernatural being would be over and above the cosmos and thus would not appear as an auxiliary player adding his 100 cents worth of interventional cause and effect every now and then; rather such a being would be a present tense continuous agent in the creation and sustenance of cosmic form. So if physics eventually provides a complete description of the cosmos, then I don’t expect such a being to appear in the final theory: Physics, after all, is about succinct descriptions and not about the deep philosophy of origins. If a description of the universe included what Larry refers to as “supernatural” beings, I would conclude that they are players very much embedded in the cosmos and would therefore be very “natural” beings like little green men or something; entities that in the past would have classified as the spirits in an animistic world view The intellectual grasp of the concept of God has much more to do with the reflexive philosophical frame of mind that must be adopted when trying to think beyond physical description to those philosophically diffuse meta-questions about ultimate origins.
3) Why is there regularity (Law) in nature?
I don't know. That's not my field.
Nicely side stepped; and just as well because in the context of physical descriptive logic such questions are unintelligible: How do we formulate a law which explains regularity in nature when that law itself must exploit a presumed regularity to be an effective explanatory object? Self referencing questions like this are not going to be intelligible let alone answered unless we are prepared to get philosophically reflexive.
Summarizing. We have, then, two very different perspectives here. Johns is saying that the kernel of fact needed to describe the universe (which must include the phenomenon of life) cannot have a complexity that is reducible to anything smaller than an “elephant sized” object. He is therefore anxious to talk up the notion of the conservation of complexity because surely big elephants are harder to explain than simple objects like mathematically elementary spheres. Larry Moran, on the other hand, probably believes in the descriptive reducibility of life in terms of physics; a point of view which I tend to support (But I have to admit it: As a great fan of physics and computer programming I could be biased. For this reason I’m prepared to entertain the view that life may be a second creative dispensation; that’s why I take seriously the work of people like Dembski and Johns). But the trouble with Larry is that he is either unaware of, or waves past the deeper questions about the ultimate origins of even simple objects (as can be seen from his responses above), questions that demand some philosophical reflexiveness.
In some areas the anti-theists and the anti-evolutionists appear to have common philosophical assumptions: I suspect that both parties share the view that as explanatory objects get more elemental, perhaps to the point of seeming to be trivial or aleatory, then a stage is reached where it is felt that no deeper reflexive explanation is needed. Thus the anti-theists feel the need to minimize the existential question by maximizing the triviality of the fundamental explanatory objects. People like Larry Moran can then wave those objects through the passport control of the critical faculties without making any probing enquiries. So, given this sort of behavior amongst anti-theists it’s no surprise that the anti-Darwinians want to keep things as irreducibly complex as they can; you might be able to smuggle a ball through passport control, but an elephant is a different matter. In my view, however, the degree of complexity of a contingent object is irrelevant to the deeper questions of its existence; the existence of a simple sphere is just as hard to explain at the philosophical level as an elephant.