If Eisenstein taught us the space time is one and the same thing, then how did he mathematicaly prove that. How did he put dimentions into his E=mc2 formula. The first 3 dimensions are strictly positions, positions in 3D require 3 numbers, and time is linear movement in one direction, the number being relative to whomever is making the measurement. My question is in order for Eisenstein's E=mc2 to have worked he needed to balance these factors in some how. How did he do it?