第25页 2.2 The meaning of probability

这一段内容是讲概率论的两种解释：贝叶斯学派和非贝叶斯学派。
概率的常规解释为随机试验中的频率，但是贝叶斯学派的观点拓广了概率的应用范围，概率还可以表示对命题的信服（belief）程度，因为这样的概率基于一些假设（assumption），所以，对概率的解释增加了主观性。
Probabilities can be used in two ways.
1. Probabilities can describe frequencies of outcomes in random experiments
2. Probabilities can also be used, more generally, to describe degrees of belief in propositions that do not involve random variables
   This more general use of probability to quantify beliefs is known as the Bayesian viewpoint. It is also known as the subjective interpretation of probability, since the probabilities depend on assumptions.
    Advocates of a Bayesian approach to data modelling and pattern recognition do not view this subjectivity as a defect, since in their view,
      you cannot do inference without making assumptions.