The procedures that relate to the ‘relative frequency’ and ‘subjective probability’ senses are clearly empirical: their outcomes depend on how the world is, not merely on how we talk about it. Accordingly, these concepts are called empirical probability concepts. Those procedures relating to the ‘degree of confirmation’ sense, however, are non-empirical: their outcomes do not depend on how the world is, but simply on the language we use to describe it and the principle of inductive reasoning that we adopted. Accordingly, this kind of probability is called logical probability. (p. 160)
Ellis, B. (1966). Basic concepts of measurement. Cambridge: Cambridge University Press.