This article is the third part of the same title (the first part is in No.61 of the same review, and the second in No. 62). In this part will be discussed some problems about universal statements. Reichenbach doesn't have a directive to construct a lattice that satisfies the requirements for schematization. When an equation has both some probabilistic factors and some parameters, how should frequencists decide them ? Frequencists and logicists ignore the regulative function of the law. There exist no universal statements in the personal interpretation. Personalists can't solve the problem of intersubjectivity. Conclusion: Those three interpretations can't be accepted Calculus of probability tells nothing about a process to assign probability to an event. What makes a probability statement bear its meaning is an explanatory theory to assign the probability to an event. The explanatory theories are the same for both single events and repeatable ones. 'Based on physical symmetry one assigns the same probability to each case' is a core and regulative principle in the explanatory theories.