Atheism and Theism JJ Haldane - Common Sense Atheism

Further Reflections on Theism 225
components of cells are proteins and nucleic acids. The latter (DNA and
RNA) carry the information that give rise to the former; while the former
are both the builders of cellular structures and catalysts of various reactions
including the replication of DNA (and the encoding of the information it
carries into ‘messenger’ RNA). Evidently an account of the origination of
cellular life needs to involve both proteins and nucleic acids, and to say how
each gave rise to the other; but given the characterization of their roles it
is unclear how an such account can escape circularity. The formation and
replication of nucleic acids depend upon the catalytic role of proteins; and production
of proteins depends upon the information encoded in the nucleic
acids. One answer may be to trace these distinct functions back to some
common molecular ‘nucleo-protein source’ in which both roles featured. As
a form of words that sounds as if it may be a solution, but logically it has the
form of saying that the chicken and egg problem can be solved by postulating
a prior entity that was at one and the same time a chicken and an egg (or at
least chickenish and eggish): a ‘chickeno-egg source’. In fact, as a solution to
the origin of life (as contrasted with that of ‘proto-life’) it does not begin
to bridge the gap between the existence of a ‘semi-replicating’ nucleo-protein
and a reactive, metabolizing, growing self-replicating, organism. This last
problem also besets the theory that life did not originate with proteins
or nucleic acids but with crystals suspended in the primitive clay. 3 On this
account the properties of life can be traced to the growth and propagation of
crystalline structures which, by stages, incorporated ‘proto-proteins’ from the
surrounding material. The difficulty is that while crystals propagate, they do
not replicate in the sense required for evolution; that is they do not encode
new information or mutate into new kinds; and nor do they interact with
their environment or exhibit any kind of metabolism. In short, they are not
living organisms even of the most primitive kind. 4
Quite apart from the complexity of the science involved in trying to
model the material conditions under which life began, the problem is in
the first instance one of conceptual coherence. This is why, if my doubts
are correct, problems of emergence are not equivalent to claims of the contingent
absence of a naturalistic developmental account. Similar difficulties
recur with further stages in the story of natural evolution. In the same
year that Atheism and Theism first appeared (1996) Michael Behe published
Darwin’s Black Box in which he argues that the existence of ‘irreducible complexity’
in biology is an impediment to naturalistic evolutionary explanations. 5
As Behe notes, Darwin himself had no conception of the biochemistry
underlying biological change and the transmission of genetic information.
His theory simply postulated random mutation leading through natural selection
to differential survival and fecundity. The main areas of subsequent
research, however, have been those of genetics and molecular biology, and