As a physicist at California Institute of Technology and the author of many books and articles, a number of them on the science of probability, Leonard Mlodinow spends a lot of time considering the question, What are the odds?

For instance, what are the odds that a single person might write — as Dr. Mlodinow has — a paper titled “Pseudo-spin Structure and Large N Expansions for a Class of Generalized Helium Hamiltonians,” a best-selling book with Stephen Hawking and at least one episode of “McGyver.” (Answer: Pretty low.)

Dr. Mlodinow has a particular, and personal, interest how the most painful events can sometimes yield unexpected results. In the first chapter of his best-seller, “The Drunkard’s Walk: How Randomness Rules Our Lives,” he writes of a conversation with his father, who tells him of how he came to survive his time in the concentration camp in Buchenwald:



It struck me then that I have Hitler to thank for my existence, for the Germans had killed my father’s wife and two young children, erasing his prior life. And so were it not for the war, my father would never have emigrated to New York, never have met my mother, also a refugee, and never have produced me and my two brothers … The outline of our lives, like the candle’s flame, is continuously coaxed in new directions by a variety of random events that, along with our responses to them, determine our fate.

He answered the following questions via e-mail:

An earlier post by the psychologist Daniel Gilbert makes the argument that uncertainty — not knowing what misfortune will come — makes people more unhappy than misfortune itself. Do you find that to be true?



It does seem to be true of my own psychology. Also, I find that what’s most important, whatever happens, is how you deal with it. And once something bad actually happens, you can start that process, and bad can eventually even turn into good.

Many people are understandably anxious and depressed about their present and future situations. Based on what you know about predictions and human behavior, should they be?



I find that predicting the course of our lives is like predicting the weather. You might be able to predict your future in the short term, but the longer you look ahead, the less likely you are to be correct. In my own life, many things that seemed to be very bad at first actually had good consequences. For example, just as I had begun making a living writing in Hollywood many years ago, the Writer’s Guild called a strike. I thought it was awful for my fledgling career, not to mention financially ruinous. But as it turned out, the strike gave busy producers a chance to catch up on their reading, and the day the strike ended I got a call from the show runner at “Star Trek: the Next Generation,” who said he read a “McGyver” script of mine he had found lying around, loved it, and wanted to hire me on the show’s writing staff. It was a plum job and a boost to my career, and it would have never happened if not for the strike.

So I try to relax, and work on making the best of whatever develops, rather than worrying about how awful it is.

In times of crisis, such as this one, are most people able to accurately predict the outcomes of situations? Or do they tend toward too much optimism or too much pessimism?



“As someone who has taken risks in life I find it a comfort to know that even a coin weighted toward failure will sometimes land on success.”

I don’t think complex situations like this one can be predicted. There are too many uncontrollable or unmeasurable factors. Afterwards, of course, it will appear that some people had gotten it just right: since there are many people making many predictions, no doubt some of them will get it right, if only by chance. But that doesn’t mean that, if not for some unforeseen random turn, things wouldn’t have gone the other way.

The social historian (and socialist) Richard Henry Tawney, wrote, “Historians give an appearance of inevitability… by dragging into prominence the forces which have triumphed and thrusting into the background those which they have swallowed up.” And the (neo)conservative historian Albert Wohlstetter said it this way: “After the event, of course, a signal is always crystal clear. We can now see what event the disaster was signaling … but before the event it is obscure and pregnant with conflicting meanings.”

In some sense this idea is encapsulated in the cliché that “hindsight is always 20/20,” but people often behave as if the adage weren’t true. In government, for example, a “should-have-known-it” blame game is played after every tragedy. In the case of Pearl Harbor, for example, seven committees of the United States Congress delved into discovering why the American military had missed all the “signs” of a coming attack. One of the pieces of evidence cited as a harbinger recklessly ignored by the U.S. Navy was a request, intercepted and sent to the Office of Naval Intelligence in Washington, that a Japanese agent in Honolulu divide Pearl Harbor into five areas and make future reports on ships in harbor with reference to those areas. Of special interest were battleships, destroyers and carriers, as well as information regarding the anchoring of more than one ship at a single dock. In hindsight , that sounds ominous, but at other times similar requests had gone to Japanese agents in Panama, Vancouver, Portland and San Francisco. [The analysis is most famously laid out in the 1963 book, “Pearl Harbor: Warning and Decision,” by Roberta Wohlstetter, who was married to Albert, noted above.]

In addition to the intelligence reports that in hindsight seem to point toward a specific attack, there is also a huge background of useless intelligence, each week bringing new reams of sometimes alarming or mysterious messages and transcripts that would later prove misleading or insignificant. In advance of the event, you can’t tell one sort from the other.

It is hard to say whether people are too optimistic or too pessimistic. That depends on the person. But we should keep in mind that it is easy to concoct stories explaining the past, or to become confident about dubious scenarios of the future. We should view both explanations and prophecies with skepticism.

Should emotions — despair, anger, happiness — play a part in the decisions people make in their lives? In other words, should our feelings matter?



Of course our feelings matter. But emotional decisions are usually not the best ones. On the other hand, your emotions can affect your decisions whether you like it or not because the effects can occur on the unconscious level. One study even showed that subjects holding a hot cup of coffee judged people differently than subjects holding a cold cup. In my case, that effect wouldn’t have been unconscious, though. I know that cold coffee makes me grumpy.

A recent news story about treating cancer told the story of one woman — a non-smoking vegetarian who exercised and had little incidence of cancer in her family — who was shocked by her cancer diagnosis. Was her reaction — and others like it — reasonable? Does “living right” work against the odds that illness or misfortune will strike us?



Assuming one is correct about the proper way to “live right” — and I’m not convinced that a straight vegetarian diet is the healthiest — it is possible to decrease the odds of bad outcomes, but that doesn’t mean they won’t occur. Anything that is possible eventually will occur, which means that some healthy-living people will get cancer, and some chain smokers won’t. I once read a story about a church group that was supposed to meet at a certain time. Ten minutes after the appointed time, due to a gas leak, the church blew up. If they had not showed up late, all 10 would have been killed. Some see that as evidence that God was watching over them. Others might conclude that you should always show up to church late. All I learn from that is that it is a big country, and if you ask around enough, you’ll hear some pretty improbable stories.

Another example, which I analyze in “The Drunkard’s Walk,” is the time Roger Maris, a very good but not great player, broke Babe Ruth’s beloved record, hitting 61 home runs in 1961. Maris had never came close to that output before, nor did he after. What happened?

We all know that players will hit a few more home runs than usual in some years, and a few less in others. But the mathematics of chance also predicts that some years they’ll hit a lot more, and some years a lot less. Those large fluctuations are rare, and wouldn’t be record-breaking for most players, in any case. But the historical statistics of baseball show that there were enough players with excellent, but sub-Ruthian, ability that over the years that it was probable that, by chance alone, one of them would have a single standout year in which they tie or break Ruth’s record. In fact, every stand-out record in any sport that has ever been analyzed has always been found to be consistent with the patterns produced by random fluctuations. Performance over time comes mainly from talent and practice. But achievements that stand out from an athlete’s usual performance — hot streaks or record years — happen with patterns that match the patterns of chance. Just wait long enough, and strange things will happen.

Can a full understanding of the probability of certain outcomes help reduce anxiety? For instance: would knowing the statistical frequency (or infrequency) of plane crashes help someone overcome a fear of flying? Would a smoker knowing the actual odds that he will get cancer make him less fearful of that outcome? In short, do we worry too much, or too little?



My mother worries too much. Some say I worry too little. I guess that shows a) that one cannot say “we” worry too much or too little, and b) that whether an individual worries too much or too little is not 100 percent inherited from your mother.

I was once on a plane that experienced so much turbulence that when I looked out the window, the wings seemed to flap up and down like a bird’s. I noticed, also, that the woman in the window seat next to me looked pale and terrified. Personally, I took comfort in knowing how many miles planes fly through heavy turbulence without any problems at all. So I explained to the woman how planes were designed to withstand such conditions, and told her the slim odds of anything bad happening. When I finished, she turned away and reached for the barf bag.

Some people take solace in an understanding of their environment, others don’t. For me, an understanding of the role played by chance has taught me that one important factor in success is under our control: the number of at-bats, the number of chances taken, the number of opportunities seized. As someone who has taken risks in life I find it a comfort to know that even a coin weighted toward failure will sometimes land on success. Or, as I.B.M. pioneer Thomas Watson said, “If you want to succeed, double your failure rate.”



Leonard Mlodinow teaches randomness to future experimenters at Caltech. His books include “The Drunkard’s Walk: How Randomness Rules Our Lives” and “Euclid’s Window: The Story of Geometry from Parallel Lines to Hyperspace.” More of his writing and information about his work can be found at his Web site.



Watch Leonard Mlodinow’s 2008 Authors@Google talk.