Theory of everything differ both from gravity and from electromagnetism. A further hurdle was the acceptance that in a TOE, quantum mechanics had to be incorporated from the start, rather than emerging as a consequence of a deterministic unified theory, as Einstein had hoped. Gravity and electromagnetism could always peacefully coexist as entries in a list of classical forces, but for many years it seemed that gravity could not even be incorporated into the quantum framework, let alone unified with the other fundamental forces. For this reason, work on unification, for much of the twentieth century, focused on understanding the three "quantum" forces:
Unified field Unified field In music, unified field is the 'unity of musical space' created by the free use of melodic material as harmonic material and vice versa. The technique is most associated with the twelve-tone technique, created by its 'total thematicism' where a tone-row (melody) generates all (harmonic) material. It was also used by Alexander Scriabin, though from a diametrically opposed direction, created by his use of extremely slow harmonic rhythm which eventually led to his use of unordered pitch-class sets, usually hexachords (of six pitches) as harmony from which melody may also be created. (Samson 1977) It may also be