The Drunkard's Walk How Randomness Rules Our Lives

by Mlodinow, Leonard

• ISBN13: 9780307275172
• ISBN10: 0307275175
• Edition: Reprint
• Format: Paperback
• Copyright: 2009-05-05
• Publisher: Vintage

Summary

With the born storyteller's command of narrative and imaginative approach, Leonard Mlodinow vividly demonstrates how our lives are profoundly informed by chance and randomness and how everything from wine ratings and corporate success to school grades and political polls are less reliable than we believe. By showing us the true nature of chance and revealing the psychological illusions that cause us to misjudge the world around us, Mlodinow gives us the tools we need to make more informed decisions. From the classroom to the courtroom and from financial markets to supermarkets, Mlodinow's intriguing and illuminating look at how randomness, chance, and probability affect our daily lives will intrigue, awe, and inspire.

Author Biography

Leonard Mlodinow received his doctorate in physics from the University of California, Berkeley, was an Alexander von Humboldt fellow at the Max Planck Institute, and now teaches about randomness to future scientists at Caltech. Along the way he also wrote for the television series MacGyver and Star Trek: The Next Generation. His previous books include Euclid's Window: The Story of Geometry from Parallel Lines to Hyperspace, Feynman's Rainbow: A Search for Beauty in Physics and in Life, and, with Stephen Hawking, A Briefer History of Time. He lives in South Pasadena, California.


From the Hardcover edition.

Table of Contents

Prologue

Chapter 1: Peering through the Eyepiece of Randomness
The hidden role of chance . . . when human beings can be outperformed by a rat.

Chapter 2: The Laws of Truths and Half-Truths
The basic principles of probability and how they are abused . . . why a good story is often less likely to be true than a flimsy explanation.

Chapter 3: Finding Your Way through a Space of Possibilities
A framework for thinking about random situations . . . from a gambler in plague-ridden Italy to Let’s Make a Deal.

Chapter 4: Tracking the Pathways to Success
How to count the number of ways in which events can happen, and why it matters . . . the mathematical meaning of expectation.

Chapter 5: The Dueling Laws of Large and Small Numbers
The extent to which probabilities are reflected in the results we observe . . . Zeno’s paradox, the concept of limits, and beating the casino at roulette.

Chapter 6: False Positives and Positive Fallacies
How to adjust expectations in light of past events or new knowledge . . . mistakes in conditional probability from medical screening to the O. J. Simpson trial and the prosecutor’s fallacy.

Chapter 7: Measurement and the Law of Errors
The meaning and lack of meaning in measurements . . . the bell curve and wine ratings, political polls, grades, and the position of planets.

Chapter 8: The Order in Chaos
How large numbers can wash out the disorder of randomness . . . or why 200,000,000 drivers form a creature of habit.

Chapter 9: Illusions of Patterns and Patterns of Illusion
Why we are often fooled by the regularities in chance events . . . can a million consecutive zeroes or the success of Wall Street gurus be random?

Chapter 10: The Drunkard’s Walk
Why chance is a more fundamental conception than causality . . . Bruce Willis, Bill Gates, and the normal accident theory of life.

Acknowledgments
Notes
Index

Excerpts

Peering through the Eyepiece of Randomness  

I remember, as a teenager, watching the yellow flame of the Sabbath candles dancing randomly above the white paraffin cylinders that fueled them. I was too young to think candlelight romantic, but still I found it magical-because of the flickering images created by the fire. They shifted and morphed, grew and waned, all without apparent cause or plan. Surely, I believed, there must be rhyme and reason underlying the flame, some pattern that scientists could predict and explain with their mathematical equations. "Life isn't like that," my father told me. "Sometimes things happen that cannot be foreseen." He told me of the time when, in Buchenwald, the Nazi concentration camp in which he was imprisoned and starving, he stole a loaf of bread from the bakery. The baker had the Gestapo gather everyone who might have committed the crime and line the suspects up. "Who stole the bread?" the baker asked. When no one answered, he told the guards to shoot the suspects one by one until either they were all dead or someone confessed. My father stepped forward to spare the others. He did not try to paint himself in a heroic light but told me that he did it because he expected to be shot either way. Instead of having him killed, though, the baker gave my father a plum job, as his assistant. "A chance event," my father said. "It had nothing to do with you, but had it happened differently, you would never have been born." 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.  

My father rarely spoke of the war. I didn't realize it then, but years later it dawned on me that whenever he shared his ordeals, it was not so much because he wanted me to know of his experiences but rather because he wanted to impart a larger lesson about life. War is an extreme circumstance, but the role of chance in our lives is not predicated on extremes. 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. As a result, life is both hard to predict and hard to interpret. Just as, looking at a Rorschach blot, you might see Madonna and I, a duck-billed platypus, the data we encounter in business, law, medicine, sports, the media, or your child's third-grade report card can be read in many ways. Yet interpreting the role of chance in an event is not like intepreting a Rorschach blot; there are right ways and wrong ways to do it.  

We often employ intuitive processes when we make assessments and choices in uncertain situations. Those processes no doubt carried an evolutionary advantage when we had to decide whether a saber-toothed tiger was smiling because it was fat and happy or because it was famished and saw us as its next meal. But the modern world has a different balance, and today those intuitive processes come with drawbacks. When we use our habitual ways of thinking to deal with today's tigers, we can be led to decisions that are less than optimal or even incongruous. That conclusion comes as no surprise to those who study how the brain processes uncertainty: many studies point to a close connection between the parts of our brain that make assessments of chance situations and those that handle the human characteristic that is often considered our prime source of irrationality-our emotions. Functional magnetic resonance imaging, for example, shows that risk and reward are assessed by parts of the dopaminergic system, a brain-reward circuit important for motivational and emotional processes. The images show, too, that the amygdala, which is

---

Excerpted from The Drunkard's Walk: How Randomness Rules Our Lives by Leonard Mlodinow
All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.