http://discovermagazine.com/2008/mar/01 ... ne-too-far ...
Has the Einstein Revolution Gone Too Far?
Einstein ended science's devotion to experience; it may now be time
to come back.
by Richard Panek
In the fall of 1919, Albert Einstein received an urgent telegram
informing him that astronomers had observed evidence of the bending
of light by the sun's gravity, validating a key prediction of his
general theory of relativity. He handed the cable to a student, who
began congratulating him. "But I knew that the theory is correct,"
he interrupted. And what, she asked, if the observations had
disagreed with his calculations? "Then I would have been sorry for
the dear Lord," Einstein answered. "The theory is correct."
There, in a nutshell, is one of Einstein's most revolutionary yet
underappreciated contributions to science. For thousands of years,
researchers had studied the behavior of the heavens and sought to
capture it in mathematical terms. Einstein reversed the challenge:
He sought truth in equations and then trusted that studies of the
heavens would back him up. Almost all of modern cosmology and
theoretical physics follows from that leap of faithor leap,
perhaps, of reason.
Einstein's first big break with tradition came while he was in his
twenties, as he pondered how light travels through a vacuum. At the
time, most scientists believed that light was rooted to some
substance embedded in empty space. But one evening in May 1905,
Einstein did what no other physicist of his era had done: He took
the math at face value. The constancy of the speed of light was
right there on paper, in James Clerk Maxwell's 1873 equations
defining the relationship between electricity and magnetism. Hence,
Einstein postulated, the constancy was right there in the universe,
too. If the speed of light is the same to all observers, he
realized, then time and space must stretch and compress so that no
matter how you are moving, light's behavior never appears to change.
From that one insight sprang the entire special theory of relativity.
As Einstein extended his thinking from space and time to gravity, he
found himself increasingly drawn to the power of the
equation. "Never before in my life have I troubled myself over
anything so much," he wrote to a friend, "and I have gained enormous
respect for mathematics, whose more subtle parts I considered until
now, in my ignorance, as pure luxury!" The result of that effort, in
1916, was general relativitythe theory that had the newly confident
Einstein telling God how the universe must work. By 1933 he had no
doubts about the path to scientific truth. Delivering the Herbert
Spencer Lecture at Oxford, he declared: "Our experience hitherto
justifies us in believing that nature is the realization of the
simplest conceivable mathematical ideas. I am convinced that we can
discover by means of purely mathematical constructions the concepts
and the laws connecting them with each other."
Following Einstein's example, subsequent physicists have discovered
previously unimaginable phenomena: dark energy, black holes, the Big
Bang. In trying to reconcile general relativity with quantum
mechanics, theorists now invoke even more exotic thingssubatomic
strings, parallel universes, and higher dimensions. These latest
concepts all exist beautifully in the mathematics, but so far
observers have identified no sign of them in the real world.
Some scientists are starting to worry that Einstein's revolution has
gone too far. Without observation to check theory, at what point
does the math devolve into game playing? Einstein, too, fretted
about that possibility in his 1933 Oxford lecture. "Experience
remains, of course, the sole criterion of the physical utility of a
mathematical construction," he said. How to move beyond slavish
devotion to experience may have been Einstein's greatest gift to the
20th century. How to bring mathematical imagination back down to
earth may rate as his greatest challenge to the 21st.
Facing that challenge will require a fresh look at Einstein, one
that ignores the caricatures and unflinchingly explores the man and
his work. It will also demand a rigorous investigation of the people
and ideas that could take us beyond Einstein's science. That process
unfolds in these other Einstein articles
