 At the core of OSCAR’s rationality is implementation of defeasible non-monotonic logic employing prima facie reasons and potential defeaters. Among its successes, Pollock claims an ability to handle the lottery paradox and preface paradoxes. Informally, the fact that we know that one of the many tickets in a lottery will win means that we must treat “ticket 1 will not win…”, “ticket 2 will not win…” and the like not as items of knowledge but as defeasible beliefs for which we have strong prima facie reasons. Pollock’s formal treatment in terms of collective defeat is nicely outlined in a supplement on OSCAR in Bringsjord &amp; Govindarajulu (2018 [2019]).