The work deploys particle physics and general philosophy of science in gravitational theory to assess what was known when about the philosophy of space-time over roughly the last century from a novel interdisciplinary perspective. Particle physicists systematically consider a wide range of options for gravitational field equations; by contrast, general relativists use conjectural quasi-aesthetic principles to rule out potentially empirically adequate theories. Since the 1950s particle physicists have derived Einstein's equations as the theory of a "massless spin 2" field, just another slot in the taxonomy of relativistic field theories. For particle physicists the conceptual innovations of General Relativity (GR) were optional until c. 1970; why not try a _massive_ spin 2 theory instead? Prima facie it approximates GR as closely as one wishes, while differing radically on most philosophical issues. To fail to entertain it is to suffer from the problem of unconceived alternatives. After setbacks in the 1970s, massive spin 2 theories have received serious attention since c. 2000 due to new experimental results such as astronomical "dark energy" (as well as dark matter) and new calculations in 2010. Thus one can either accept the right theory _for the right reasons_, or find an interesting rival(s). Such work sheds normative light on the recent re-evaluation of Einstein's discovery process and on motivations for quantum gravity projects. The output will be 6 journal-submitted articles to show the transparent rational basis for Einstein's equations (or a related rival!) in a philosophically and historically informed way. An intended outcome is to dispel the view that GR transcends ordinary rationality. Harmonizing good science with good philosophy of science should make an enduring impact of strengthening scientific rationality, making good science more accepted and distinguishing it from bad science via conformity to normative methods.