3 ms·
uh oh we got a badass over here. The point of my argument was to express a "practical" epistemology in which Newton's successes represent exactly what they acc
by sixo 1y ago
uh oh we got a badass over here.
The point of my argument was to express a "practical" epistemology in which Newton's successes represent exactly what they accomplished, instead of some failure to live up to an ideal "truth", a view which I consider useless and pedantic.
> One cannot absorb the idea of a "force" into GR.
Yeah you can, tho I never learned the specifics. IIRC, a force is a Lagrange multiplier representing a constraint on the extremization of action. When you extremize a joint system (two particles A and B interacting) you just get some exchange of momentum between them and no force appears. But if you extremize just A w.r.t to a known and fixed trajectory of B, B's influence on A appears as an "external force" term. This is actually all "forces" ever were—constraints relating dp_A/dt and dp_B/dt—but this fact is obscured in Newton because we typically think of systems with their external forces factored out, which of course lets us apply useful approximations for gravity, air resistance, friction, etc.
You can certainly do the same operation in GR of isolating a subsystem of a joint system and you will find a "force" term, it has to be there just as a logical consequence of the extremization process. I thought this was well known. Or do you mean "one cannot absorb..." in some other sense?
My mistake tagging you as a philsci person, tho. I regret the error!
- d4rkn0d3z 1y ago'Yeah you can, tho...' I can do no such thing. The idea of a "force" as known to Newton, being "action at a distance" by "mutual attraction", is not at all present in GR.