The Monty Hall problem usually features goats, not sheep. But the grazing herd above does not mind. I recently introduced the Monty Hall problem to someone who, like most people newly exposed to the problem, expressed dismay at the solution. Today, someone posted the problem on 3 Quarks Daily (one of my favorite blogs). So, it’s only natural that I should re-post here. The problem demonstrates the inability of most people to grasp the nature of probability. Even mathematicians have struggled to comprehend the problem. Still, the solution is not in doubt.