# Bayesian probability

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Revision as of 23:03, 25 October 2009 by Vladimir Nesov (talk | contribs) (Undo revision 5109 by PeerInfinity (Talk))

**Bayesian probability** represents a level of certainty relating to a potential outcome or idea. This is in contrast to a frequentist probability that represents the frequency with which a particular outcome will occur over any number of trials.

An event with Bayesian probability of .6 (or 60%) should be interpreted as stating "With confidence 60%, this event contains the true outcome", whereas a frequentist interpretation would view it as stating "Over 100 trials, we should observe event X approximately 60 times."

The difference is more apparent when discussing ideas. A frequentist will not assign probability to an idea, either it is true or false and it cannot be true 6 times out of 10.

## Blog posts

- Probability is Subjectively Objective by Eliezer Yudkowsky
- Probability is in the Mind by Eliezer Yudkowsky
- When (Not) To Use Probabilities by Eliezer Yudkowsky
- All Less Wrong posts tagged "Probability"