Quantum theories can be formulated in many different ways, but what is probably the most intuitive description was given by Richard Feynman, a colorful character who worked at the California Institute of Technology... According to Feynman, a system has not just one history but every possible history, as we seek our answers, we will explainFeynman's approach in detail, and employ it to explore the idea that the universe itself has no single history, nor even an independent existence. that seems like a radical idea, even to many physicists. indeed, like many notions in today's science, it appears to violate common sense. but common sense is based upon everyday experience, not upon the universe as it is revealed through the marvels of technologies such as those that allow us to gaze deep into the atom or back to the early universe.
Hawking, Stephen. Leonard Mlodinow. 2010. The Grand Design. New York: Bantam Books.