Bayesian probability interprets the concept of probability as 'a measure of a state of knowlege' . Broadly speaking, there are two views on Bayesian probability that interpret the 'state of knowledge' concept in different ways. For the objectivist school, the rules of Bayesian statistics can be justified by desiderata of rationality and consistency and interpreted as an extension of Aristotelian logic. For the subjectivist school, the state of knowledge corresponds to a 'personal belief' . Many of the modern machine learning methods are based on objectivist Bayesian principles .