Brian Leftow

This article provides an explanation of Anselm’s understanding of necessity. Anselm did not write much about modality, and what he did write is puzzling. The dominant readings of Anselm see him as having two concepts of necessity, one merely physical or causal, the other logical or “alethic.” This article argues that Anselm has just one concept of necessity, which corresponds best to what is now called broadly logical or absolute necessity, but whose metaphysics is in terms of powers and lacks of power. The rival interpretations of A. D. Smith, Thomas Williams, and Sandra Visser are discussed and criticized in detail.

Western theists agree that God is eternal. But they disagree over what eternality is. This chapter clarifies one view of eternality, that of Boethius, and shows that some aspects of this view are coherent. On Boethius' view, God is not temporal. The chapter first gives a minimal account of what it is to be temporal. This account explains what sets Boethius' view of God's eternality apart from others. It is shown that Boethius' view implies that though God's life is not temporal, there are events in it, and these events have what is typically a temporal property: they occur in a present. The chapter argues that these are coherent claims.

This essay by Brian Leftow provides an account of the nature and extent of God’s freedom. Theists typically believe that God could have done other than He has done. Many think that God gives them gifts He need not have given. Most Western philosophical theologians have held that God had the choice not to create, for instance. While there is general agreement that God has some leeway, there is disagreement over how much He has. The central point is a defense of a voluntarist rather than a rationalist account of the extent of God’s live options: God is not bound to effect the best, where the sort of value in question is nonmoral.

Brian Leftow offers a theory of the possible and the necessary in which God plays the chief role, and a new sort of argument for God's existence. It has become usual to say that a proposition is possible just in case it is true in some 'possible world' (roughly, some complete history a universe might have) and necessary just if it is true in all. Thus much discussion of possibility and necessity since the 1960s has focussed on the nature and existence (or not) of possible worlds. God and Necessity holds that there are no such things, nor any sort of abstract entity. It assigns the metaphysical 'work' such items usually do to God and events in God's mind, and reduces 'broadly logical' modalities to causal modalities, replacing possible worlds in the semantics of modal logic with God and His mental events. Leftow argues that theists are committed to theist modal theories, and that the merits of a theist modal theory provide an argument for God's existence. Historically, almost all theist modal theories base all necessary truth on God's nature. Leftow disagrees: he argues that necessary truths about possible creatures and kinds of creatures are due ultimately to God's unconstrained imagination and choice. On his theory, it is in no sense part of the nature of God that normal zebras have stripes (if that is a necessary truth). Stripy zebras are simply things God thought up, and they have the nature they do simply because that is how God thought of them. Thus Leftow's essay in metaphysics takes a half-step toward Descartes' view of modal truth, and presents a compelling theist theory of necessity and possibility.

"Anselm of Canterbury gave the first modal "ontological" argument for God's existence. Yet, despite its distinct originality, philosophers have mostly avoided the question of what modal concepts the argument uses, and whether Anselm's metaphysics entitles him to use them. Here, Brian Leftow sets out Anselm's modal metaphysics. He argues that Anselm has an "absolute", "broadly logical", or "metaphysical" modal concept, and that his metaphysics provides acceptable truth makers for claims in this modality. He shows that his modal argument is committed to the Brouwer system of modal logic, and defends the claim that Brouwer is part of the logic of "absolute" or "metaphysical" modality. He also defends Anselm's premise that God would exist with absolute necessity against all extant objections, providing new arguments in support of it and ultimately defending all but one premise of Anselm's best argument for God's existence"--

Jeff Speaks has recently argued that perfect being theology treating God as the greatest possible being—he calls it alethic perfect being theology—cannot deliver new information about God. This argument is central to his critique of all forms of perfect being theology. For as Speaks sees it, other forms of perfect being theology may collapse into alethic perfect being theology, i.e. fail in the end to be a different sort of project. I lay out how he understands alethic perfect being theology and then contest his argument.

This article provides an explanation of Anselm’s understanding of necessity. Anselm did not write much about modality, and what he did write is puzzling. The dominant readings of Anselm see him as having two concepts of necessity, one merely physical or causal, the other logical or “alethic.” This article argues that Anselm has just one concept of necessity, which corresponds best to what is now called broadly logical or absolute necessity, but whose metaphysics is in terms of powers and lacks of power. The rival interpretations of A. D. Smith, Thomas Williams, and Sandra Visser are discussed and criticized in detail.

Brian Leftow makes an important contribution to the longstanding debate among philosophers and theologians about the nature of God's eternity. The author develops a powerful and original defense of the notion that God is eternal in that he exists timelessly; that is, that though God exists, he does not exist at any time. Leftow defends the claim that a timeless God can be an object of human experience, and he attempts to delineate the extent of such a God's omniscience. Finally, the author pays special attention to the relation between the claim that God is timeless and the claim that God is metaphysically simple.

Medieval philosophers distinguished God from all else by calling Him supremely one. Realists about properties affirmed God's special unity by arguing either that God cannot be conceived to be without His properties or that God wholly lacks the real complexity having properties involves. ;This thesis examines the latter, more radical doctrine of divine simplicity. On this doctrine, for all F, what makes God F differs in no way from what makes Him God. ;If all truths about God have the same truth-condition, they all are materially equivalent. Their predicates' senses seemingly must shift in divinis to allow this unusual equivalence. Many medievals concluded from this that God is simple, it is impossible to say anything comprehensible about Him and in particular to ascribe to Him personal attributes. ;By distinguishing sense- from application-fixing properties associated with predicates, I so analyze talk of a simple being as to give it comprehensible sense. I argue that we can ascribe a simple God the sort of knowing involved in understanding a proposition and that this renders such a God "personal enough" for religion. ;If coherent, the radical doctrine of divine simplicity follows from God's being the most perfect logically possible being on the assumptions that something is a better F the less likely it is to cease being F and that being "one with one's Fness" involves more "unity" with one's Fness than does being necessarily F. Divine simplicity entails God's timelessness, immutability, uniqueness and aseity. It also entails two conditionals, that if God wills, He is omnipotent and that if God knows, He is omniscient. By tracing out these connections I show that divine simplicity brings to a concept of God both systematic neatness and plausible explanations for God's having many of His traditional attributes