A better way to think about this is with tennis. When playing tennis, you have to decide where you think the ball is going to bounce in order to return it. Bayes’ rule gives you two sources of information in order to make this prediction. One is sensory evidence: You see the ball coming toward you. But your senses are far from perfect. Furthermore, there could be spin on the ball, or wind affecting the ball flight, or it could be moving so rapidly that you don’t get a clear idea of where it’s headed. Instead of taking the sensory input as a certainty, you instead consider it a likelihood—the
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