Waddington, Bateson, Evolution, and Cybernetics

摘要

Both Waddington and Bateson, long term friends since student days, argued that genetic effectiveness was part of a more complex model than neo-Darwinian notions of natural selection plus mutation provide. Waddington urged an approach to evolution in which causal change is investigated at a whole range of different loci-an epigenetic landscape-including situations where patterns of learning in phenotypes evoke processes by which phenotypic response to the environment is overtaken by a genotype at a later point of time. Waddington called this genetic assimilation. It did not sit well with Bateson. Bateson acknowledged that Waddington's laboratory simulation of Baldwin processes (or genetic assimilation) was valid, but argued that this would not occur as a general process in the natural world since a single feedback of the same logical type could not carry both normal adjustments to environmental change, normal adaptation, and carry feedbacks about systemic change. At a later stage Bateson would reject Waddington's argument for a socio-genetics on the grounds that here too is a confusion of logical types. Cultural domains exhibit forms of feedback different from either the somatic or the genetic. "The Role of Somatic Change in Evolution" is all about this dispute but raises difficulties for the reader because its personal history is unexpressed. For a while their dispute became quite bitter, so in this article another developmental biologist, K. S. Thompson, is cited as an imaginary referee. Thompson shows that there is an ongoing circularity, in which processes occurring at one level contribute to constraints at another level, and recursive feedback between the genetic and epigenetic components is required in any complex system for it to anticipate how increasing information will affect its own future pattern.