Micro Mooc #3. The law of large numbers is the most important thing in life and science. It is the basis of epistemology and problem of induction. How many observations do you need to know if something is true? We get into the plumbing and show how it is too slow under fat tails. This is a simplified (but technical) presentation of a segment of “Probability and Risk in the Real World”, the Technical Companion for The Black Swan http:// www. fooled by randomness. com/ FatTails. html