I mean, beyond the physical argument... has people (scientists) worried about to justify why the configuration space of Nature should compactify to 3+1? In a previous thread, we found (we=marcus+me+orion+rest of readers if any) that gravitational coupling constant simplifies out of some equations only if the force law is inverse square. This rings a bell: inverse square law is, arguably, consistent only with 3D space. Thus any "dimension-independent proof" of inverse square law should also justify us to compactify into 3D space. So, second question... any papers on this?