27 November 2008

Symbolic and other inheritance systems

Can we guide our own evolution?

Yes, because changing our own habits changes the context in which natural selection operates.

No, because we don't control the effects of what we do. Some of those effects are always unanticipated, and you don't control what you can't anticipate.

Eva Jablonka has identified four different ‘inheritance systems’ which have roles in evolution: genetic, epigenetic, behavioral, and symbolic. For the full story see Jablonka and Lamb, Evolution in Four Dimensions (2005). Since the discovery of DNA and its structure, the genetic inheritance system has dominated evolutionary theory, but the other three are finally being recognized as sources of variation on which natural selection can operate.

Of course language — the primary symbolic system — has long been recognized as a source of variation on which conscious selection can operate. Biosemiotics, based on the pioneering work of Peirce, is beginning to bridge the gap between natural and conscious selection as factors in evolution — just as Jablonka has done, except that semiotics begins with the symbolic (linguistic) level and works downwards while Jablonka and colleagues are working upwards from the genetic.

My blog post yesterday commented on some similarities between the genetic and symbolic inheritance systems (GIS and SIS) which are not shared by the other two: both are modular and combinatorial. This allows them both to encode information, a vitally important function in the evolutionary process, as Jablonka points out:
Because of the ability to encode information, both the GIS and SIS transmit a lot of unexpressed information. Nonfunctional genes are transmitted, as also are nonimplemented ideas. This provides a huge reservoir of variation, which may become useful in new conditions. I believe that this ever-present potential gives these systems a particularly important role in long-term evolution. However, no inheritance system acts in isolation: inheritance systems interact both directly and indirectly. For example, the social animal, with its behavioral information systems, determines the selective regime in which genes are ultimately selected.
— Jablonka (Oyama, Griffiths and Gray 2001, 112)

This implies that in a time of crisis like the one we are now living through, we can affect the course of our own evolution by consciously changing our actual habits to realize ideas which have already been ‘transmitted’ but not yet implemented. That may sound obvious, but i wonder whether the possibility has really ‘sunk in’ to our awareness. Maybe it can help to place it on a scientific basis, as Jablonka does, and as Peirce did a century ago.

1 comment:

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