Apologies for not doing too much research prior to asking this question; I suppose actually delving into the mathematics would reveal the answer I'm looking for but I haven't taken the time just yet. Considering the concept of GR where matter/energy tells space how to curve and space tells how matter to move, how do we avoid the feedback that would be cause by space telling matter to move faster which in turn increases the energy/matter of moving body? (in such a case wouldn't the metric then be a function of itself) ? could such a metric exist? or no? or could it exist but simply not satisfy the field equations?