Not a physicist, but my understanding (from having glanced at one of Einstein's 1905 papers a long time ago) was that the genesis of SR has a context. Specific

Not a physicist, but my understanding (from having glanced at one of Einstein's 1905 papers a long time ago) was that the genesis of SR has a context. Specifically, the following observations bothered Einstein (below are my words, don't think anyone from 1905 would say it this way): 1. Maxwell's equations did not permit information to propagate faster than some finite velocity c, which (for many good reasons) can be identified with the speed of light in vaccuum. 2. Closely related mathemaical fact: Maxwell's equations were Lorentz invariant. 3. On the other hand if one envisioned a charged particle moving in a field, then Newtonian theory says the particle dynamics were galilean invariant. But the particle and the field really are part of one system, and it would be odd for the two parts to have different symmetry properties, as this would mean for example that when one changes between two coordinate systems their equations of motion would transform in different ways. I know lots of you know way more physics & history of physics than I. Please jump in!