Summary: Philosophy of Science, 75 (October 2008) pp. 479485. 0031-8248/2008/7504-0008$10.00
Copyright 2008 by the Philosophy of Science Association. All rights reserved.
Richard Healey, Gauging What's Real: The Conceptual Foundations of
Contemporary Gauge Theories. Oxford: Oxford University Press (2007),
240 pp., $99.00 (cloth).
This well-researched and authoritative book provides much material
for philosophers of physics to discuss and debate. It is significant in par-
ticular for the attention it gives to non-Abelian Yang-Mills gauge theories
(the theories that appear in the Standard Model), and the structural dif-
ferences between them and the gauge theories that have typically appeared
in the philosophical literature (i.e., Abelian electromagnetism and general
relativity [GR]). Healey's specific goal is to defend an interpretation of
Yang-Mills theories under which
(a) they refer to nonlocal properties encoded in holonomies; and
(b) the local gauge symmetries that characterize them are purely formal
and have no direct empirical consequences.
A holonomy is a quantity associated with a closed curve. Under one
representation, it is determined by the line integral along the curve of a
gauge potential field. After a presentation of classical Yang-Mills theories
in Chapter 1, Healey devotes Chapter 2 to the Aharonov-Bohm (AB)