GR lacks absolute space, but does Newtonian physics also? If not what does GR lacking absolute space mean? I had thought in Newtonian physics that there existed an absolute space in which Newton's laws are true, and that an inertial frame was a reference frame in relative uniform motion to absolute space. Is that wrong? I was given the impression by a staff member here that it was, and I was advised not to read the wikipedia article ( https://en.wikipedia.org/wiki/Galilean_invariance ) which stated: Among the axioms from Newton's theory are: There exists an absolute space, in which Newton's laws are true. An inertial frame is a reference frame in relative uniform motion to absolute space. All inertial frames share a universal time. But I find that somewhat confusing because in the Stanford Encyclopedia of Philosophy it also states https://plato.stanford.edu/entries/newton-stm/ "Newton defined the true motion of a body to be its motion through absolute space." What I particularly found confusing is while I had pointed out, using a wiki article ( https://en.wikipedia.org/wiki/Absolute_time_and_space ) that "...within the context of Newtonian mechanics, the modern view is that absolute space is unnecessary. Instead, the notion of inertial frame of reference has taken precedence, that is, a preferred set of frames of reference that move uniformly with respect to one another" the staff member replied not that yes he held the modern view that absolute space was unnecessary, but stated that I had misunderstood what absolute space meant. So if anyone could clear up that misunderstanding that would be useful, as before coming to the forum I had not realised that I had misunderstood it. I had thought GR lacking absolute space meant that its inertial frames should not be thought to be reference frames moving relative to absolute space, to that there was no true movement as I think Newtonian stated.