Yet Einstein's theories do not say this, at least not in the way many people think. And certainly, Einstein's ideas of relativity have nothing to do with whether we should believe in God, as many people seem to think, assuming Einstein to have been the ultimate pure-science atheist. Einstein was a theist, believing that a creator is present but rejecting organized religion. He penned such thoughts as, "God reveals himself in the orderly harmony of what exists." Had Einstein chosen only slightly different words for his work, he might have sent the century an entirely different message.
In 1905, Einstein published his first big idea: the Special Theory of Relativity. This postulate held that physical laws are the same for all observers regardless of position and speed; that the speed of light is always the same from all points of view; and that matter and energy are equivalent (that's the E=MC2 part). For techno-reasons we can skip here, applying these three assertions overturned classical, or "Newtonian," physics, which assumed that the universe is simply a gigantic version of the same effects seen on Earth. Under the Special Theory of Relativity, for example, there is no fixed length for an object. To an observer standing on Earth, a 10-foot pole is 10 feet long; to an observer in a spacecraft at high velocity, it may appear five feet long. Neither is the "correct" dimension; both are equally valid relative to perspective. Under the Special Theory, time can "dilate," seeming to move at different rates from different perspectives. In unusual circumstances, even the order of events may become unclear. That is, two different observers might have opposite opinions on whether A came before B or B came before A.
Clearly, Einstein believed that his physical laws that always applied from all perspectives could lead to mind-bending results, such as time dilation. But most of the mind-bending results Einstein foresaw had to do with "relativistic" velocities for matter or with extremely dense amounts of mass, conditions that are rare even at the cosmic scale. Under typical conditions, even typical conditions for stars and supernovas, the assumptions of the Special Theory help us understand why the universe is stable and comprehensible, rather than pandemonium. Considering his premises that the speed of light is always the same and physical laws are always reliable and predictable, Einstein might as easily have called his first work the Special Theory of the Cosmic Absolutes.
Then there is his second great achievement, the General Theory of Relativity, published in 1915. In this theory, Einstein struggled with the question of why the universe does not fly apart; he came to the conclusion that gravity orders the heavens by giving an unseen but powerful shape to space-time. (Collectively, Einstein's two hypotheses are spoken of as a single theory.) Parts of the General Theory of Relativity are spooky and hard to grasp. Einstein supposed, for example, that space appears flat to us but would appear curved from the perspective of someone outside the universe. In turn, he thought that gravity functions by bending local space-time, such that when an apple falls, what it's doing is rolling down a curvature we cannot perceive.
Did Einstein choose the name he did because, as is often suggested, he was a revolutionary who wanted to assail stodgy conventional thinking? Perhaps, yet in many ways Einstein was a scientific square. He opposed the Big Bang theory, asserting that the Greeks were right and the universe is eternal. He didn't like the theory of cosmic expansion, preferring to think of the heavens as forever static. Einstein was very uncomfortable with quantum mechanics, which holds that some subatomic effects happen without A-causes-B linkage and that there is no firm or "ponderable" subatomic particle on which reality is based. (Einstein thought the idea that physical events can happen without causation was just too weird for words.) And though Einstein was cool to organized religion, especially to the notion that God controls daily events, he was a reverent man who often spoke of his awe for the Creator who made the firmament. That wild hair aside, Einstein was not an advocate of "anything goes." He dreamed of a universe of ordered constants--simply different constants than the ones assumed by classical physics.
"Relativity" was a fashionable word in intellectual commentary when Einstein chose this term for his theories, and if he was trying to give his work a memorable name, as some of his writings suggest, no one can object to that. Yet how might this century's thinking have been different if its leading mind had simply chosen to emphasize the word "absolute" rather than the word "relativity"? Today, millions of people believe that Einstein's work proved, via detached science, that nothing is true and it's all relative. Actually, Einstein proved that some very basic things are always and utterly true--a much different point of view than modernity assumes.