 William Ockham  (c.1285–1347), a highly influential Christian philosopher and theologian from the medieval period, suggested an interesting way of accounting for God’s knowledge of the contingent future and resolving the problem of prophecy. (For more detailed presentations of Ockham’s views, see the introduction to Ockham 1983 by Adams and the introduction to Molina 1988 by Freddoso.) Ockham claims that what a prophet has truly revealed about the contingent future “could have been and can be false” (Ockham Predestination, 44), even though the existence of the prophecy in the past is “ever afterwards necessary” (Ockham Predestination, 44). As Calvin Normore puts it, “After God has revealed a future contingency it is necessary that the physical or mental things he used to reveal it have existed, but what is revealed is not necessary” (Normore 1982, 373). In terms of our example involving Jesus’ prophecy concerning Peter’s denial, Ockham’s idea is that were Peter to choose freely not to deny Jesus instead, then Jesus would never have prophesied that Peter would deny him. (Some philosophers like to call this kind of proposition a “back-tracking counterfactual”, because it is a subjunctive conditional statement whose consequent refers to an earlier time than its antecedent.) In other words, if a person were about to choose freely to do something, then God would have known about it from eternity, and hence would have acted accordingly. 