Contribution
A centennial address surveying how symmetry and invariance, long implicit in physics, became central after Einstein. Wigner proposes that invariance principles relate to laws of nature as laws relate to events, supplying coherence rather than new content. He separates the classical, geometrical space-time invariances from newer dynamical invariances belonging to particular interactions, reviews how the geometrical ones yield conservation laws, and discusses what the dynamical groups (gauge, general relativity, strong and weak interactions) do and do not imply about conservation.
Skim
Abstract, figures and selected sections, read when the work was seeded. Not enough to state its assumptions or results exactly; a Read note replaces this one.
- Introduction (p. 956–957): the link between conservation laws and space-time symmetry (credited to Hamel, 1904) is now accepted “perhaps too generally”; symmetry has been extended to areas far from direct experience.
- Events, Laws of Nature, Invariance Principles (pp. 957–958): if all events were known, laws would add no information; likewise if all laws were known, invariance principles would add none — they structure the laws as laws structure events.
- Geometrical vs dynamical (pp. 958–959): geometrical principles are stated in terms of events (e.g. correlations depend only on time differences); dynamical ones in terms of specific interactions (gauge invariance of electromagnetism); the interaction groups are disjointed and not predictable in advance.
- Geometrical principles and conservation (pp. 959–961): in quantum mechanics conservation follows from kinematics alone — the rotation operator commutes with time evolution (Fig. 1); classically it needs extra assumptions (Newton’s third law, central two-body forces).
- Dynamic principles (pp. 961–963): gauge invariance and general covariance are read as invariance of different descriptions of the same situation, not geometric invariance (following Fock); charge conservation follows from gauge invariance, while baryon/lepton conservation suggests the proper groups of strong/weak interactions are not yet recognised.
Open questions
- A classic source for the laws/invariance-principles hierarchy and for the geometrical/dynamical distinction that later philosophy of symmetry (Brading, Castellani, Earman) builds on.
- Check how the “general covariance is dynamical, not geometrical” claim compares with later debates on the physical content of diffeomorphism invariance (cf. Belot, LIT-122).
- Parts of the particle-physics discussion (1964 SU(3) status) are dated; the philosophical framing is what remains current.