# Bayesian probability

From Lesswrongwiki

**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

- What is Bayesianism?
- Probability is Subjectively Objective
- Probability is in the Mind
- When (Not) To Use Probabilities
- All Less Wrong posts tagged "Probability"
- Gadgets
- Blog

## See also

## External links

- BIPS: Bayesian Inference for the Physical Sciences
- Maximum entropy thermodynamics