Paul P. Mealing

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Saturday, 18 October 2008

Emergent phenomena

A couple of weeks ago in New Scientist (4 October 2008), there was one of those lesser featured articles that you could skip over if you were not alert enough, which to my surprise, both captured and elaborated on an aspect of the natural world that has long fascinated me. It was titled, ‘Why nature is not the sum of its parts’.

It referenced an idea or property of nature, first proposed apparently by physicist, Philip Anderson, in 1972, called ‘emergence’. To quote: ‘the notion that important kinds of organisation might emerge in systems of many interacting parts, but not follow in any way from the properties of those parts.’ As the author of the article, Mark Buchanan, points out: this has implications for science, which is reductionist by methodology, in that it may be impossible to reduce all phenomena to a set of known laws, as many scientists, and even laypeople, seem to believe.

The article specifically discusses the work of Mile Gu at the University of Queensland in Brisbane, Australia, who believes he may have proved Anderson correct by demonstrating that mathematical modeling of the magnetic forces in iron could not predict the pattern of atoms in a 3D lattice as one might expect. In other words, there should be a causal link between individual atoms and the overall effect, but it could not be determined mathematically. To quote Gu: “We were able to find a number of properties that were simply decoupled from the fundamental interactions.” To quote Buchanan quoting Gu: ‘This result, says Gu, shows that some of the models scientists use to simulate physical systems have properties that cannot be linked to the behaviour of their parts.’

Now, obviously, I’ve simplified the exposition from an already simplified exposition, and of course, others, like John Barrow from Cambridge University, challenge it as a definitive ‘proof’. But no one would challenge its implication if it was true: that the physics at one level of nature may be mathematically independent of the physics at another level, which is what we already find, and which I’ve commented on in previous posts (see The Universe’s Interpreters, Sep.07).

This is not dissimilar to arguments produced in some detail by Roger Penrose in Shadows of the Mind, concerning the limitations of formal mathematical reasoning. According to Penrose, there are mathematical ‘truths’ that may be ‘uncomputable’, which is a direct consequence of Godel’s ‘Incompleteness Theorem’ (refer my post, Is mathematics evidence of a transcendental realm? Jan.08). But Penrose’s book deals specifically with the enigma of consciousness, and this is where I believe Anderson and Gu’s ideas have particular relevance.

I would argue, as do many others (Paul Davies for one) that consciousness is an ‘emergent’ phenomenon. If science is purely reductionist in its methodology, as well as its philosophy, then arguably, consciousness will remain a mystery that can never be solved. Most scientists dispute this, including Penrose, but if Anderson and Gu are correct, then the ‘emergent’ aspect of consciousness, as opposed to its neurological underpinnings, may never be properly understood, or be reducible to fundamental laws of physics as most hope it to be.

2 comments:

Nate said...

This does not surprise me. Gravity exists because it's a law external from other connections, why it is a law no one can say. There is a disconnection somewhere, however philosophers generally hate to reference 'because it just it' as any sort of justification.

Paul P. Mealing said...

Hi Nate,

Not quite: Einstein demonstrated, mathematically, that gravity is a direct consequence of the curvature of space and time, caused by mass.

One could call gravity an 'emergent' property, but then you would have to say the same about electric charge or anything else that is manifest as a 'force field', and that's not quite what I meant.

You, yourself, are an emergent entity arising from an assemble of trillions of cells, that cannot be accounted for by looking at the cells themselves.

Even your DNA is really a code (like software code): a set of instructions that allows you to be assembled. But the emergent human being, that is you, would never be predicted except by reverse engineering. In other words, it's only because we know what your traits are (by studying you and others) that we can correlate them with your genes (DNA).

Nature is far more mysterious than even we can imagine.

Regards, Paul.