 Whether our objective beliefs are true depends on their verifiable or confirmable implications for future possible experience. However, in order to guide action effectively now while saving us from the hazards of action without foresight, empirical belief and its expectations for experience must be justified (rationally credible, warranted) now, antecedent to future verification (Lewis 1946, 254–7). Justification, as opposed to verification, is the focus of AKV much more so than MWO. Nonetheless, throughout Lewis’ career from MWO to the end, there are common claims. First, empirical knowledge (rationally credible, justified, or warranted belief) is probable knowledge or belief. Second, probability is a logical or inferential relation between a conclusion or a belief and its premises or grounds. Third, the ultimate premises or grounds relative to which a conclusion or belief is probable, as opposed to more immediate or proximate ones, cannot themselves be probable but must be certain (Lewis 1929, 328–9, 340–1; Lewis 1946, 186–7; Lewis 1952a).