Conned Again, Watson: Cautionary Tales of Logic, Math and Probability
by Colin Bruce
Vintage, £7.99, ISBN 0099428571
This book fizzes with ideas, paradoxes and problems, drawn mainly from logic, probability and statistics, and presented in a Sherlock Holmes setting. As you might expect, poor Dr Watson blunders from error to error, from which he is rescued, contemptuously, by Holmes. Topics include the birthday paradox, the drunkard’s walk, various gambling fallacies, Pascal’s triangle, the Wason test, the Monty Hall problem, the mark-releaserecapture procedure for estimating population sizes, and there are also introductions to Bayesian logic and game theory. So, a great deal is crammed into the book’s 288 pages.
As always with a book like this, the question arises: Who is it intended for? Certainly, anyone who is studying, or has studied, probability and statistics will probably find that it illuminates familiar ideas, and also introduces some new ones. On the other hand, it is doubtful whether a complete beginner will learn very much, unless they either approach the book with dogged determination, or else have a strong natural aptitude for the subject. Indeed, the only major criticism of the book is that it attempts too much, and so skims over important points. For example, this applies to one of the key problems relating to probability (pages 103–106), and readers should certainly visit the author’s web site for an additional explanation.
Also, lovers of Conan Doyle’s stories are warned that they will find, in every other paragraph, something to make them wince – not merely the many anachronisms to which the author freely admits (such as Lewis Carroll writing Alice in Wonderland two years after his death), but, more especially, the language. For example, Conan Doyle’s Holmes would never have counselled Watson to “recharge his batteries”, and Watson would never have been so ungentlemanly as to address a clergyman as “Reverend”, or use the word “pub”.
But, in sum, it’s an entertaining and lively book. Recommended.
