|
Chaos
and antichaos
Natural
selection only works on what already exists, and we need therefore to
understand what is it that “creates” novelties in life. An answer to this
question comes from the ancient words of Democritus – “everything in
the Universe is the fruit of chance and necessity” – which gave Jacques
Monod the title of his famous book (1970) and its main thesis: “chance
alone is at the source of every innovation, of all creation in the biosphere.
Pure chance, absolutely free but blind, is at the very root of the stupendous
edifice of evolution”.
Ernst Mayr, one of panselectionism’s founding fathers, sharply reprimanded
Monod for not accepting that natural selection works at all levels, including
the molecular one, and is the one and only source of novelties for all
living creatures. In The Growth of Biological Thought (1982), and
later in One Long Argument (1991), Mayr delivered his charge with
blunt clarity: “Monod failed to understand the explanatory power of
natural selection and opted for pure chance as having been responsible
for the phenomena of nature. Such Epicureanism, however, is only rarely
encountered in modern times”.
To Mayr’s rhetoric, however, neatly replied Kimura’s mathematics with
the demonstration that “at the molecular level most evolutionary change
and most of the variability within species are not caused by natural selection
but by random drift”. This takes us to a unique conclusion: at the
molecular level evolutionary novelties can be created either by the chaos
of genetic drift or by an antichaos mechanism which is not natural
selection.
Experience has taught us that we must firmly reject all forms of antichaos
that have been proposed in the past, because they invariably ask us to
give up understanding and embrace mystery, but this does not mean that
we must abandon a rational search for an antichaos that could really
exist in nature. Our best guide, in this endeavour, is again mathematics,
and here we will turn once more to the reconstruction method.
A particularly useful hint comes from the very simplest of the algorithms
that were described in Chapter 3 (Density Modulation).
|