 Lewis appreciated the problem memory posed for his epistemology much more clearly in AKV than in MWO. In AKV, Lewis (1946, 334) argued that whatever we ostensibly remember, whether as explicit recollection or merely in our sense of the past, is prima facie credible just because so remembered. So there are data of sense presentation and also data of “seeming to remember” or “present memory” (Lewis 1946, 353, 354) that constitute our ultimate evidence, and it is only through the latter and the principle of memorial prima facie credibility that empirical generalizations and the beliefs they support can be inductively supported by premises about past experience as well as about directly apprehended present experience. Further the credibility of our recollections, together with the whole range of empirical beliefs more or less dependent on them, can be solidified and increased through the mutual support or congruence of the whole, or can be diminished through incongruence. 