# Talmudic koan?

A new (to me) version of an old story:

A man goes to his rabbi and says, “Rabbi, I would like to study Talmud.” The rabbi says, “Excellent. Let us begin. Two men go up a chimney together; one comes down clean, the other dirty. Which one washes himself?” The man says, “Why, the dirty one, of course.” The rabbi says, “Not so. Go home and think about it for a week, and bring me a different answer.”

In a week, the man returns and says, “Now I have it. They look at each other. The dirty man, seeing his clean companion, has no idea that he himself is dirty. The clean man, seeing his dirty companion, thinks himself soiled, so he goes and washes himself. So the clean man washes himself and the dirty one does not.” The rabbi says, “Not so. Go home and think about it for a week, and bring me a different answer.”

A week later, the man returns and says, “Yes, yes, a very nice problem! But I’ve finally cracked it. The clean one, seeing the other dirty, goes to wash himself, and his companion, hearing the running water, looks down and recognizes his own soiled state. So they both wash.”

The rabbi says, “A good, subtle analysis. But not so. Go home and think again, and bring me a different answer.”

In a week, the man returns, looking puzzled. “I think I see it now. The clean man, seeing his companion dirty, looks down at himself and sees that he is clean. He knows, then, that he need not wash himself, but perhaps he is too polite to tell his companion to wash. The other, seeing his fellow clean, and not prompted by the sound of the water, never looks at himself. So neither one washes. Is that right?”

The rabbi sadly shakes his head. “Very subtle indeed, but not so. Go home and try again.”

The man loses it. “Rabbi, I don’t know what sort of game you’re playing! You asked which of two men washed. Either the one, or the other, or both, or neither. Yet each of those you rejected as the wrong answer. Anyway, the entire problem is ridiculous! If two men go up a chimney together, how could one come down clean? They’d both be filthy from head to toe!”

The rabbi smiles. “Excellent! Now you’re ready to study Talmud. We meet tonight at eight.”

## Author: Mark Kleiman

Professor of Public Policy at the NYU Marron Institute for Urban Management and editor of the Journal of Drug Policy Analysis. Teaches about the methods of policy analysis about drug abuse control and crime control policy, working out the implications of two principles: that swift and certain sanctions don't have to be severe to be effective, and that well-designed threats usually don't have to be carried out. Books: Drugs and Drug Policy: What Everyone Needs to Know (with Jonathan Caulkins and Angela Hawken) When Brute Force Fails: How to Have Less Crime and Less Punishment (Princeton, 2009; named one of the "books of the year" by The Economist Against Excess: Drug Policy for Results (Basic, 1993) Marijuana: Costs of Abuse, Costs of Control (Greenwood, 1989) UCLA Homepage Curriculum Vitae Contact: Markarkleiman-at-gmail.com