Grand Unified Theory
Einstein's Interrupted Dream
Quantum Theory advanced steadily through the early 20th century—and so did Einstein's discontent with it. The theory predicts how discrete packets of energy, called quanta, will behave based on statistical probabilities instead of direct observations. Einstein liked some aspects of Quantum Theory, but he never accepted its statistical basis as a means to completely describe the physical world.
He thought this new branch of physics did not embrace the harmonious way in which God created the universe.
"Quantum mechanics is very worthy of regard. But an inner voice tells me that this is not yet the right track. The theory yields much, but it hardly brings us closer to the Old One's secrets." Instinct drove Einstein to spend his last decades struggling to mesh the subatomic and universal realms under one "Grand Unified Theory." But his gut feeling eventually gave in to doubt. "All my attempts, however, to adapt the theoretical foundation of physics to this new type of knowledge failed completely," he wrote. "It was as if the ground had been pulled out from under me...." Yet Einstein hoped that his work would point modern physics in a new direction. Physicists today still pursue the Grand Unified Theory.
Describing the Universe
Roughly half a century has passed since Einstein ceased his pursuit of one "theory of everything," but many physicists today continue the chase for a Grand Unified Theory in an attempt to understand the nature of matter, energy, space, and time.