Conservation and Innovation : Helmholtz's Struggle with Energy ...

The premise reveals that the structure of the Erhaltung is based on four
relevant methodological layers 73: a) to establish two physical assumptions
("physikalischen Voraussetzung": central Newtonian forces and impossibility of
perpetual motion) and their equivalence 74; b) to derive from them as a
consequence ("Folgerungen") a theoretical law ("die Herleitung der aufgestellten
Sätze": the principle of conservation of energy) 75; c) to compare this general
principle with the empirical laws ("erfährungsmässigen Gesetzen") which connect
the d) natural phenomena ("Naturerscheinungen") in various fields of physics 76.
Helmholtz thus not only plans to offer, at variance with most of the other
researchers involved with conservation problems, a specific functional
formulation 77 of the quantities conserved and of their interrelations, but also a
derivation of this "principle" from more general physical assumptions. This is an
implicit assertion of the possibility of alternative versions of the principle.
But the great theoretical innovation is that empirical laws are supposed to
be compared no longer only with natural phenomena, but also with a general
principle. It is not difficult to understand Magnus' and Poggendorff's perplexities
in the evaluation of the essay: the young physiologist without presenting new
experimental results adds two levels (a, b) to the standard practice of
(experimental) physicists - that of formulating empirical laws (c) which would fit
natural phenomena (d).
One of the first conscious criteria of demarcation between theoretical and
empirical science can now be drawn 78: while the experimental scientist is looking
for empirical generalisations that fit experimental data (e.g.: the refraction and
reflection laws), the theoretical scientist looks for the agreement of the principle
of conservation with existing empirical laws (justificatory role of the principle)
and for the theoretical discovery of new ones (heuristic role). Helmholtz here is
explicitly setting out the task of theoretical research for the following decades:
agreement with principles will become a condition which empirical laws have to
satisfy, as important as the agreement with experimental data.
73 Helmholtz Erhaltung P.1
74 To be done in section 1
75 In section 2
76 In sections 3, 4, 5, 6.
77 A general framework that allowed energy terms, while retaining some constant
features, to acquire diferent expressions in different applications.
78 Helmholtz Erhaltung P.2