That's exactly what Larson's Reciprocal System unified theory says: particles are in contact if they are either adjacent in 3D space or 3D time.
Space/Time? That's SO last-millenium!
Beyond space-time: Welcome to phase space
http://www.newscientist.com/article/mg21128241.700-beyond-spacetime-welcome-to-phase-space.html?full=true
http://arxiv.org/PS_cache/arxiv/pdf/1101/1101.0931v2.pdf
We do not live in spacetime. We live in Hilbert space, and the classical approximation to that is that
we live in phase space. (4 space-time dimensions, and 4 curved momentum-space dimensions)
