Technology. Technology unites man because everytime it is used, or thought of, we are reminded that human cooperation took place to create the technology. Why not language, art, music, food and mortality? Because technology has greater potential for work. Then why not work? Why can't we say work unites man? Work is not an absolute unifying concept because it is rarely thought of during leisure and survival, and has been throughout history a reason to separate.

Why can we not say more absolute concepts than technology are the reason for unifying man? Because technology is tangible and common.