Sometimes referred to as the grand unified theory (GUT), and the holy grail of some physicists, it is the search for a theory that would bring together all known phenomena to explain the nature of all matter and energy in existence as well as, for example, the underlying symmetries of nature. It is a descendant of the claim made by Pierre-Simon Laplace (1749-1827) around 1814 that if we knew the position and velocity of every single particle in the universe as well as the laws that governed them, then we could work out (with enough computing power) the state of the universe and everything in it. Unfortunately, it was a claim that did not survive the uncertainty principle of Werner K. Heisenberg (1901-1976). The present motivation to achieve a TOE derived from the frustrating inability to reconcile Einstein‚was general theory of relativity that deals with gravitation and explains the nature and behaviour of phenomena at macroscopical level, with quantum mechanics that addresses much less predictable ones at the microscopical (atomic and sub-atomic) levels. Finding the magic equation that would embrace both theories is what the search is all about, and Einstein failed in this respect in attempting to find a unified field theory. Since then, other theories have emerged that go well beyond Einstein‚was attempt at unification such as string theory (everything in the universe is made of loops on vibrating strings in a multidimensional space, even down to the level of bosons and quarks), superstring theory (everything amounts to vibrations on tiny super symmetrical strings), and M-theory (an as yet unknown ToE that would combine all five superstrings and 11-dimensional supergravity, and which requires mathematical tools still to be devised). All sound a bit crazy? Welcome to wacky world of the ToE!
See Bridge laws, Causal determinism, Determinism, Paradigm shift, Quantum mechanics, Self-organisation