ESHS/HSS Annual Meeting

Patchwork Gravity: From Geometric Unity to Methodological Pluralism

• In Event: Shifting Perspectives on Histories of Gravity and Mass 2

English Abstract

The mid-twentieth-century debate over gravitational radiation was, as Trautman (1958) noted, a debate over analogy: whether general relativity behaved more like Newtonian mechanics or electrodynamics. The two main approximation schemes embodied that divide. The post-Newtonian method, inaugurated by Einstein, Infeld, and Hoffmann (1938), recovers relativistic corrections to Newtonian dynamics but shows no gravitational waves at low orders. The post-Minkowskian approach, used by Einstein (1916), treats gravity as a perturbation of flat spacetime, producing wave equations and the quadrupole formula, though at the cost of linearizing away general relativity’s geometric unity. Even Einstein wavered on whether gravitational radiation is real.
From the 1950s to the 1970s, work by Bondi (1957, 1962) on energy loss, the peeling behavior identified by Sachs (1961), Penrose, and Newman (1962), and the discovery of the Hulse–Taylor binary pulsar (1974) shifted the consensus toward accepting gravitational waves as real, energy-transporting phenomena. Yet the resolution did not come from choosing between approximation methods but from combining them. Fock (1955) had already proposed matching near-zone post-Newtonian expansions with far-zone post-Minkowskian ones. His contribution—overlooked partly due to his insistence on harmonic gauge and his Marxist philosophical commitments—proved prescient (Kennefick 2007). By the 1980s, hybrid formalisms such as Blanchet–Damour and DIRE realized and perfected the matching strategy.
This paper traces that transformation and argues that the modern view of general relativity as a patchwork of regionally valid approximations marks a shift from the pursuit of unity to an embrace of methodological pluralism—one that resonates with Nancy Cartwright’s account of patchwork science. It shows how mature pluralism in gravitational-wave science grew out of historical, institutional, and local conditions that shaped attempts to solve global scientific problems.

Author

• Shelly Yiran Shi, UC San Diego