 Thus, in AKV, Lewis (1946, 305) claimed that the full statement of a probability judgement should be of the form “That \(c\), having property \(F\), will also have property \(G\), is credible on data \(D\), with expectation \(a/b\) and reliability \(R\)”, and is assertable in whatever sense \(D\) is. The judgement is valid when, in accordance with the a priori rules of probability and the correct rules of judging reliability, \(D\) gives the estimate \(a/b\) of the frequency of \(F\)s among \(G\)s, and \(D\)’s adequacy, uniformity, and proximateness to the case in point, yields reliability \(R\). A valid probability judgement is true when \(D\) is true, and is a categorical rather than a hypothetical judgement when \(D\) is categorically asserted as true. The assertion of the empirical data \(D\) is the only empirical element in the probability judgement, which otherwise has no testable implications for experience. However, the belief \(P\), that \(c\) which has \(F\) is also \(G\), is an empirical belief that may be rationally credible, empirically justified, and warranted, in so far as \(D\) is given and the degree of assurance or belief corresponds to an a priori degree of probability (expectation) of \(P\) on \(D\) that is sufficiently reliable. Further, acceptance of \(P\) counts as empirical knowledge in so far as, firstly, \(P\) is true, secondly, the degree of probability or expectation of \(P\) on \(D\) is sufficiently high as to approach practical certainty, and, thirdly, \(D\) consists of all relevant data (Lewis, 1946, 314–15).