"The foundational aspects of physics during the first
half of the twentieth century have been principally concerned
with the characterization of the 'elementary' constituents of
matter and the elucidation of the nature of the space-time framework
in which their interactions take place. The discovery [1897]
of the **electron** by [Joseph John]
Thomson, the precise characterization of its **charge** by
Millikan, the demonstration of the nuclear **atom** by Rutherford,
the **photon** hypothesis of Planck and Einstein, and Bohr's
explanation of the spectrum of hydrogen were some of the landmarks
of that history. These early efforts culminated in the mid-twenties
with the formulation of quantum mechanics by Heisenberg, Dirac,
and Schrödinger (Kuhn 1978; Heilbron 1975; Segrè
1980; Pais 1986; Mehra and Rechenberg 1982-1988). Our
brackets to avoid potential confusion. Lord Kelvin's name was
William Thomson.
"The revolutionary achievements in the period from 1925
to 1927 stemmed from the confluence of a theoretical understanding
(the description of the dynamics of microscopic particles by
quantum mechanics), and the apperception of an approximately
stable ontology (**electrons** and **nuclei**). Approximately
stable meant that these particles (electrons and nuclei), the
building blocks of the entities (**atoms**, molecules, simple
solids) that populated the domain that was being carved out,
could be treated as **ahistoric** objects (whose physical
characteristics were seemingly independent of their mode of production
and **whose lifetimes could be considered as essentially infinite**).
These entities could be assumed to be 'elementary' pointlike
objects that were specified by their mass, spin, and statistics
(whether **bosons** or **fermions**), and by electromagnetic
properties such as their charge and magnetic moment." (Our
bold.)
Paragraphs 2 & 3 from Silvan S. Schweber's
*QED and the Men Who Made It:*
Dyson, Feynman, Schwinger, and Tomonaga.
'Introduction,' p. xxi
PUP, 1994 |