text: A Theory of Everything (TOE) is the name given to attempts to view the four fundamental forces of the universe: \n\n1. gravity\n2. electromagnetism\n3. the weak force (responsible for radioactivity)\n4. the strong force (keeps the atomic nucleus together) \n\nas just different aspects of the same thing. This was worked on by Einstein towards the end of his life for quite a few years. So far, forces 1&2 have been reliably unified (as electromagnetism was the theory resulting when electricity and magnetism were unified). The unification of 1,2 and 3 looks like it might have been done, but has not yet been verified completely. There are many theories to unify all 4 of the forces, including the recent varieties of string theory, but no one knows how to check these.