What Helium Teaches Us about the Success and Failure of Dynamical Theories

Abstract

Philosophers have typically explained predictive success through some sort of
referential relationship between theoretical terms (entities, properties, structures) and
objects of reality. Through a case study of the successes and failures of Bohr’s atomic
model, in particular as it pertains to helium, I argue that more complicated relations are
needed to adequately explain both the successes and failures of a dynamical theory.
Bohr’s problem was not a matter of “failure of reference”, i.e. Bohr’s energy levels not
lining up with the actual energy levels, but rather a matter of “failure of tracking”, which
is a matter of incompatibility between the theoretical state assignments and the underlying
transitions among the states. Unlike reference, which is a static notion, tracking is
irreducibly dynamic: it is a matter of cooperation between how the states are assigned and
how they evolve. As a result of this, unlike reference which tends to be global and
referentially transparent, tracking is local and referentially opaque.