The doctrine of middle knowledge was developed by the Spanish Jesuits Luis de Molina and Francisco Suarez in the late sixteenth century, and immediately became the subject of fierce controversy, being bitterly opposed by the Dominicans, especially Domingo Bafiez and Diego Alvarez, and requiring the intervention of the Vatican (in 1607) to cause the bitterness to subside. As recent work has shown, the intellectual interest of the doctrine extends far beyond that of an inhouse debate in the Catholic Church of the Counter-Reformation; for it touches on issues of central importance not only in analytic theology, but also in philosophical logic. According to Molina, there are three moments in God's foreknowledge of the history of the world which He creates.' These moments are not to be thought of as stages in a temporal series, but as ordered by the relation of logical or conceptual dependence of later on earlier.2 In the first moment, God knows by natural knowledge all metaphysically necessary propositions. These include not merely truths of logic and mathematics, and natural laws, but also facts about which contingent states of affairs are possible, since that a state of affairs is possible is itself a necessary truth. God's natural knowledge would suffice to equip Him with complete foreknowledge of the history of His creation, if the world He created were entirely deterministic, and if He undertook to refrain from free intervention in that world. The creation