Is gravity both a force and not a force?

[Geometry_dude]

In science, if you can never detect it, you can safely ignore it and let Occam's razor cut it away.

I was trying to point out a conceptual inconsistency in Newtonian mechanics. Had Einstein ignored it, we would not have general relativity today.

Before dealing with gravity and general relativity, one should ask and answer an analogous question in Newtonian mechanics: Is inertial force a force or not a force? After answering that one, the gravity case is conceptually much easier.

Yes, that's what I meant with 'forces' causing 'relative acceleration'.