Random ? Is the Cosmos

Few of Albert Einstein’s sayings have been as widely quoted as his remark that God does not play dice with the universe. People have naturally taken his quip as proof that he was dogmatically opposed to quantum mechanics, which views randomness as a built-in feature of the physical world. When a radioactive nucleus decays, it does so spontaneously; no rule will tell you when or why. When a particle of light strikes a half-silvered mirror, it either reflects off it or passes through; the outcome is open until the moment it occurs. You do not need to visit a laboratory to see these processes: lots of Web sites display streams of random digits generated by Geiger counters or quantum optics. Being unpredictable even in principle, such numbers are ideal for cryptography, statistics and online poker. Einstein, so the standard tale goes, refused to accept that some things are indeterministic—they just happen, and there is not a darned thing anyone can do to figure out why. Almost alone among his peers, he clung to the clockwork universe of classical physics, ticking mechanistically, each moment dictating the next. The dice-playing line became emblematic of the B side of his life: the tragedy of a revolutionary turned reactionary who upended physics with relativity theory but was, as Niels Bohr put it, “out to lunch” on quantum theory. Over the years, though, many historians, philosophers and physicists have challenged this story line. Diving into what Einstein actually said, they have found that his thinking about indeterminism was far more radical and nuanced than is commonly portrayed. “It becomes a kind of a mission to get the story right,” says Don A. Howard, a historian at the University of Notre Dame. “It’s amazing when you dig into the archives and see the disparity from the common narrative.” As he and others have shown, Einstein accepted that quantum mechanics was indeterministic—as well he might, because he was the one who had discovered its indeterminism. What he did not accept was that this indeterminism was fundamental to nature. It gave every indication of arising from a deeper level of reality that the theory was failing to capture. His critique was not mystical but focused on specific scientific problems that remain unsolved to this day. The question of whether the universe is a clockwork or a craps table strikes at the heart of what we suppose physics to be: a search for simple rules that underlie the wondrous diversity of nature. If some things happen for no reason, they mark the limits of rational inquiry. “Fundamental indeterminism would mean an end to science,” worries Andrew S. Friedman, a cosmologist at the Massachusetts Institute of Technology. And yet philosophers throughout history have supposed that indeterminism is a prerequisite for human free will. Either we are all gears in the clockRNDOM ?