Sunday, May 19, 2013

Denis Noble's paper is published - and Lee Smolin seems to be missing some points

Denis Noble is also a Trobador
Denis Noble's ground breaking paper "Physiology is rocking the foundations of evolutionary biology" is now formally published in Experimental Physiology.  The abstract reads as follows:

The ‘Modern Synthesis’ (Neo-Darwinism) is a mid-20th century gene-centric view of evolution, based on random mutations accumulating to produce gradual change through natural selection. Any role of physiological function in influencing genetic inheritance was excluded. The organism became a mere carrier of the real objects of selection, its genes. We now know that genetic change is far from random and often not gradual. Molecular genetics and genome sequencing have deconstructed this unnecessarily restrictive view of evolution in a way that reintroduces physiological function and interactions with the environment as factors influencing the speed and nature of inherited change. Acquired characteristics can be inherited, and in a few but growing number of cases that inheritance has now been shown to be robust for many generations. The 21st century can look forward to a new synthesis that will reintegrate physiology with evolutionary biology.

He shows that "all the central assumptions of the Modern Synthesis ...have been ways that raise the tantalizing prospect of a totally new synthesis; one that would allow a reintegration of physiological science with evolutionary biology." and offers the following Comparison between the Modern Synthesis and the proposed Integrative Synthesis.

Before: Modern Synthesis Now: towards an Integrative Synthesis
Gene-centred view of natural selection Selection is multilevel
Impossibility of inheritance of acquired characteristics Acquired characters can be inherited
Distinction between replicator (genes) and vehicle (phenotype) The genome is an ‘organ of the cell’, not its dictator. Control is distributed
The central dogma of molecular biology Genomes are not isolated from organism and environment

This is incredibly exciting and it will be very interesting to see how it is taken up.

Meanwhile I see that Lee Smolin is carrying on with the idea that evolution through black holes can explain anthropic fine tuning. We dealt with this in Questions of Truth and since I actually discussed these issues face to face with Lee it's somewhat disappointing that we aren't cited. In brief the problems are:
  • You need a proper time into which you can embed all the (hypothetical) universes in the multiverse, otherwise it makes no sense to talk about the evolution of a population. This is deeply problematic, and in this proper time short-lived universes with a few "descendants" will  dominate longer-lived universes with many "descendants".  There is also the problem that some universes (esp with Lambda >0) have an infinite lifetime and generate infintely many black holes. These will "out-compete" any finite universes on a generation number basis.
  • Even if we grant the heroic assumptions needed, Smolin's evolutionary principle might explain why the present parameters were more likely than others, but not the apparent fine-tuning.
PS I've now looked at the paper "Cosmological natural selection and the purpose of the universe" by Andy Gardner and Joseph P. Conlon "which looks into the formalism of Lee's Cosmological Natural Selection. They assume that the relevant set is "generations" of universe although they do note the problem (without acknowledgement or citation).  They don't seem to have noticed the second problem - I'll email them.

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