Physicists sometimes indulge in an entertaining but largely pointless debate about which of their two ­pre­eminent geniuses, Isaac Newton or Albert Einstein, deserves the ­all-­time number one ranking. Hans Ohanian has no doubts on the matter. Newton is worth several Einsteins, he tells us, although it would have been more in keeping with the frequently pedantic spirit of his book if he had let us know exactly how many ­Einsteins—­three? four and a quarter?—stack up to one Newton. At one point, Ohanian even suggests that Einstein wasn’t quite up to the level of Max Planck, the founder of quantum theory, but by the end of 

 he has restored Einstein to the number two position. Putting Einstein in his place seems, at any rate, to be Ohanian’s main ­purpose.

Though recent biographies have largely dispelled the cherished myth that Einstein was a dunce at school, it is true that the great physicist was not a natural mathematician. After making the enormous conceptual leap that connected the phenomenon of gravitation to the fact that space-time is curved, it took Einstein many excruci­ating years to find the appropriate mathematical expression for this idea and thereby create the theory of general relativity. Einstein’s earlier attempts, some published, some abandoned, contained deep flaws. In his other revolutionary achievements too, Einstein’s first pronounce­ments were rarely the last word. Over the years, those original insights were painstakingly polished to become the scientific theories we know today, and often it was other physicists—more rigorous than Einstein, if less imaginative—who filled in the gaps and supplied the finishing ­touches.

This, by and large, is nothing more than how science ordinarily progresses, but Ohanian, a former editor at the 

 and author of several text­books, seems intent on finding in the missteps and fudges of Einstein’s papers a new and shocking portrait of the man. Einstein’s pre-1905 efforts “have faded into the obscurity they richly deserve.” He made blunders in his great works of 1905 because he “was not thinking like a physi­cist, but like a patent clerk.” A mistake in the first attempt to prove that E = mc2 “is the sort of thing every amateur mathematician knows to watch out for.” And so ­on.

There is, to be sure, the germ of an interesting story here. Einstein’s arguments were often make­shift and occasionally shoddy, but most of the time he knew where he wanted to go and found a way to get there. That, as Ohanian

ad­mits, is one definition of genius, but he shows little interest in pursuing the thought. Instead, facing up to the evident truth that Einstein re­peatedly hit on answers to difficult puzzles before he could figure out a convincing justification for them, Ohanian can only throw up his hands and declare that Einstein was “a mystic in the throes of a revelation.” In his minute analysis of Ein­stein’s works, Ohanian reveals himself to be the kind of strictly logical, ­step-­by-­step physicist that Einstein plainly was not, and Ohanian’s inability to cope with that difference almost seems to have turned into a personal ­animosity.

This is a scientific rather than a personal study, but still, Ohanian finds time to mention the less attractive aspects of Einstein’s character: his shabby treatment of his first wife, his neglect of his children, his tendency to slight his col­leagues’ scientific contributions, his dreadful sartorial sense, his love of certain disgustingly heavy German foods. Only in the later chapters, when the aging Einstein has come to America to spend his final years working fruitlessly on a “theory of everything,” does the tone soften. An eccentric, rather lonely figure, Einstein turns at last into a dotty old uncle whom Ohanian can regard with pity instead of ­scorn.

 Uncertainty: Einstein, Heisenberg, Bohr, and the Struggle for the Soul of Science.

Einstein's Mistakes: The Human Failings of Genius

 by Hans C. Ohanian, Norton, 394 pp, 2009.

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Hans C. Ohanian's analysis of Einstein's works, "reveals himself to be the kind of strictly logical, step-by-step physicist that Einstein plainly was not, and Ohanian's inability to cope with that difference almost seems to have turned into a personal animosity."

Einstein, Relatively Speaking

Stars as well as human beings are born, grow old, and die. In the 19th century scientists proposed the dismaying notion of the "heat death” of the universe, according to which every hot thing becomes tepid while all cool things become warm, so that in the end all matter exists at the same middling temperature and the future is an eternal unchanging tedium. Physicists have a word for this general tendency toward decay and dissipation: entropy. And entropy, as Sean Carroll, a physicist and cosmologist at the California Institute of Technology, ably explains, is all about the directionality of time. The onward march of time fundamentally derives from something peculiar about the way the universe was born, and that’s the puzzle Carroll attempts to resolve.

If you could watch a movie of two atoms bashing into each other and then bouncing apart, you could not tell which way time was running. A collision run backward in time obeys the laws of mechanics exactly as well as the same collision run forward. But think of a lot of atoms crashing about - milk being stirred into black coffee, for example - and a clear direction of time emerges. Stir that coffee as long as you like, and you will never see the milk collect itself in one spot to form a white island in a black sea.

Entropy, you may have heard, explains this. Entropy is a measure of disorder, and the second law of thermodynamics says that it can only increase. Highly ordered arrangements of atoms (the milk all in one place, surrounded by coffee) inevitably evolve, through the general commotion of atoms, into disorderly arrangements (the milk mixed up throughout the coffee). The fundamental reason is simple: There are far more disorderly arrangements than orderly ones, so, as a matter of straightforward probability, changing systems are more likely to end up in disordered states.

Having set out these basic ideas with great lucidity, Carroll delivers the kicker. It’s all very well to say that systems tend to go from low probability states to high-probability states, and that that progression is fundamental to our sense of time marching forward, but who said that we have to start from a place of low probability? If the initial point of any system, whether we’re talking about milk in coffee, life on Earth, or the big bang itself, were drawn randomly from the list of all possible states such a system might be in, it most likely would be a high-probability state with, entropically speaking, nowhere to go. Why, that is, wasn't the universe born into a state of heat death—by far the most likely state for any universe?

For a century or more, physicists have had to simply assume that the universe began in a special state endowed with low entropy, so as to allow thermodynamic room for all the interesting later stuff (galaxies, planets, people) to happen. But that’s an uncomfortable assertion, because saying that the universe must have started in some special way implies a deep reason for that specialness that we haven’t been able to figure out yet. Carroll claims that at least the glimmer of an explanation is finally in sight. To support that conclusion he travels through deep and mysterious realms of physics, ranging from the existence of time machines to the fate of quantum information swallowed by black holes. Carroll is an affable and enthusiastic guide, but I suspect many readers will need to take frequent time-outs to let their minds unboggle.

In his final chapter, Carroll draws on the increasingly commonplace (to cosmologists, anyway) idea that our universe is just one of many. In the picture he sketches, each universe grows old and boring in line with the classical idea of heat death, but in its dotage it can spawn baby universes that start with low entropy and live through an exciting phase of growth and activity before becoming boring themselves, so continuing the cycle. We know that we live in just such an exciting phase because our universe still has a lot going on. As for how elderly universes give birth to new ones, and why those young’uns start life with low entropy, you’ll have to read Carroll’s book, and you’ll have to pay attention.

Carroll is admirably honest in acknowledging the degree of speculation here. It’s legitimate to worry, I think, that his low-entropy baby universes only come about because he has put together a number of unproven physical assumptions in just the right way. The specialness that he and other cosmologists are so eager to explain away may be there still, having been flushed out of one dark corner only to scurry into another.

Uncertainty: Einstein, Heisenberg, Bohr, and the Struggle for the Soul of Science

"From Eternity to Here: The Quest for the Ultimate Theory of Time" 

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For a century or more, physicists have assumed that the universe began in a special state endowed with low entropy — but that’s an uncomfortable assertion.

David Lindley