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names and concepts of biochemistry were not reduced to the underlying physi-
cal chemistry (in the sense of reduction of theories to underlying more general
theories, cf. above). Similarly, 'the' structure of nucleic acids and proteins was
determined by X-ray crystallography, but the question of whether that structure
was stable with respect to the physical forces between amino acids and between
bases, was not addressed. This was in part because it could not be addressed
effectively. Virtually none of these structures can presently be calculated ab initio
(see (Popelier & Joubert, 2002) for an example), precisely because the interac-
tions are nonlinear, and with many interactions depending on other interactions.
Likewise, electric field effects on transmembrane movements of ions cannot be
vested in physics and chemistry because too much of the details of the transport
matters and is in fact unknown. Although there has been some progress in the
calculation of enzyme catalysis in terms of physical-chemical interactions, most
such reaction mechanisms cannot be verified in terms of precise physics and
chemistry. The same is true for the pathways of processes that make living cells
operate. The fluxes through them cannot be calculated ab initio either, but only
from direct physical-chemical interactions and atomic structures. In biochemical
textbooks, pathways are therefore drawn as roadmaps running through many
towns and connecting major cities or hubs (Barabási & Oltvai, 2004). Indeed,
reduction of molecular biology and biochemistry to the underlying physics and
chemistry is rare, and not even an aim of these disciplines anymore; both dis-
ciplines are entirely successful on the basis of their own concepts and laws,
immaterial whether these are reducible to physics and chemistry or not. How-
ever, this general problem of intractability in terms of the underlying physics and
chemistry caused reluctance among many physicists and chemists to consider
biochemistry and molecular biology as serious sciences. The biology of entire
living systems was observed to be too complex and ill defined for the hypotheses
to be strict, testable and falsifiable. To some, this made molecular biology and
biochemistry appear to remain stamp collecting.
Indeed, the above limitations suggest that neither biochemistry nor molecular
biology connect to physics. They fail to meet the criteria of classical physics
that were once proposed to be the criteria of proper science (Carnap, 1966).
Looking at chemistry beyond quantum chemistry, this may not be a novelty
among the experimental sciences; chemistry may not connect to physics either
(Primas, 1981).
2.5. Lack of testability because of undefinedness
Another important limitation of biochemistry and molecular biology relates
more literally to holism. Returning to Eqn (1), we realize that the Michaelis
'constant' is independent of the concentration of S but not necessarily constant
otherwise. Agents binding to the enzyme catalysing the reaction may influence
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