What Is Life? - Molecular Theory of the Living Cell - page 565

statements about life such as (16.7), (16.9), and (16.10) that are based solely on the
laws of physics and chemistry cannot be considered complete (or sufficient), since
such statements lack the Thirdness (Sect. 6.2.2 ) aspect of life, namely, the genetic
information engendered by biological evolution. Thus I am inclined to suggest that:
No theory of life can be complete without incorporating the irreducible triad of energy ,
entropy , and genetic information . (16.11)
The theories of life expressed by Schrodinger and Prigogine in Statements 16.6
and 16.9, respectively, are primarily concerned with the energetic and entropic (i.e.,
thermodynamic and chemical kinetic) aspects of life and offer little or no guidance
as to the informational (or evolutionary) aspect of life. But, since the discovery of
the DNA double helix by Watson and Crick in 1953, an enormous amount of
experimental data has been generated in molecular and cell biology, most of
them having to do with genetic information. Any purported theory of life must
take this fact into account and provide rational explanations for it. From this
perspective, Statements 16.6 and 16.9 above must be deemed necessary but not
sufficient to account for life. One of the primary objectives of this topic has been to
formulate a molecular theory of life that is consistent with Statement 16.11, thereby
filling the theoretical gaps left behind by Schr

odinger and Prigogine.

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16.5 Life According to Pattee

By extending the earlier theoretical work of von Neumann on self-replicating
automata (von Neumann 1966), Pattee (1968, 1995) formulated what he referred
to as the matter-symbol complementarity, according to which all self-replicating
and evolving systems (including organisms) possess two complementary aspects -
the physical law-governed material/energetic aspect and the evolutionary rule-
governed symbolic aspect . As pointed out by von Neumann, there are in principle
two ways of accomplishing self-replication - by self-inspection followed by copy-
ing and assembling the copied parts, and by self-description using symbols (and
more generally using signs as defined by Peirce [Sect. 6.2.1 ]) followed by executing
the resulting instructions to self-replicate. Of these two possibilities, von Neumann
concluded, without providing any proof, that the direct copying method is too
inefficient and that the second symbolic method was preferred. Pattee developed
von Neumann's original idea into his matter-symbol complementarity , which may
be represented as in Scheme 16.12 :

Matter þ Symbol ! Biological Functions (16.12)

where biological functions include self-reproduction or self-replication.
Scheme 16.12 is consistent with what is actually found in all living systems, for
example, the DNA-based mechanism of self-reproduction. But Pattee and von
Neumann did not provide any realistic molecular mechanisms for connecting