# Degrees of belief

One of the three major interpretations of probability (besides relative frequencies and propensities). The probability of an event is the subjective degree of belief a person has in that event. Historically, degrees of warranted belief entered probability theory from applications in the courtroom, such as the credibility of witnesses. Degrees of belief are constrained by the laws of probability (for example, probabilities need to add up to 1), that is, beliefs need to follow these laws to qualify as subjective probabilities.