Drunkard's Walk - Leonard Mlodinow [0]
Title Page
Dedication
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
Also by Leonard Mlodinow
Copyright
To my three miracles of randomness:
Olivia, Nicolai, and Alexei…
and for Sabina Jakubowicz
PROLOGUE
A FEW YEARS AGO a man won the Spanish national lottery with a ticket that ended in the number 48. Proud of his “accomplishment,” he revealed the theory that brought him the riches. “I dreamed of the number 7 for seven straight nights,” he said, “and 7 times 7 is 48.”1 Those of us with a better command of our multiplication tables might chuckle at the man’s error, but we all create our own view of the world and then employ it to filter and process our perceptions, extracting meaning from the ocean of data that washes over us in daily life. And we often make errors that, though less obvious, are just as significant as his.
The fact that human intuition is ill suited to situations involving uncertainty was known as early as the 1930s, when researchers noted that people could neither make up a sequence of numbers that passed mathematical tests for randomness nor recognize reliably whether a given string was randomly generated. In the past few decades a new academic field has emerged to study how people make judgments and decisions when faced with imperfect or incomplete information. Their research has shown that when chance is involved, people’s thought processes are often seriously flawed. The work draws from many disciplines, from mathematics and the traditional sciences as well as cognitive psychology, behavioral economics, and modern neuroscience. But although such studies were legitimated by a recent Nobel Prize (in Economics), their lessons for the most part have not trickled down from academic circles to the popular psyche. This book is an attempt to remedy that. It is about the principles that govern chance, the development of those ideas, and the manner in which they play out in politics, business, medicine, economics, sports, leisure, and other areas of human affairs. It is also about the way we make choices and the processes that lead us to make mistaken judgments and poor decisions when confronted with randomness or uncertainty.
Information that is lacking often invites competing interpretations. That’s why such great effort was required to confirm