Brian Leftow

Most debate in the philosophy of religion centres on “thin theism,” the thesis that there is a deity who is omnipotent, omniscient, etc. But few if any theists are just thin theists. For most, thin theism is at best the abstract skeleton of a fuller set of religious beliefs— Christian, Jewish, or Moslem. Thus, there is another set of issues philosophers of religion might but rarely do discuss: with what sort of warrant might one add to thin theism the beliefs of a particular religious tradition? In other words, supposing that thin theism is true, what reasons might there be to be, say, a Christian? Is Christianity True? takes up this last question. Successive chapters ask whether there would be moral benefit in worshipping the Christian God, whether it is reasonable to accept Christianity’s distinctive claims though other traditions which embed thin theism deny them, whether the doctrine of the Incarnation makes sense, whether the doctrine of the Atonement is morally acceptable, whether we know enough about Jesus’s sayings and doings to warrant Christian claims about him, whether the doctrine of the Trinity is coherent, and whether there is a coherent conception of life after death; an appendix takes up Marx on religion.

Augustine, Aquinas and many other medievals held the doctrine of divine simplicity (DDS) -that God has no parts of any sort. Augustine took this to imply that for any non-relational attribute F, if God is F, God = Fness. This can seem to create three problems. I set them out. Having done so, I show that Augustine's DDS is set within a view of attributes now unfamiliar to us. When we bring this into the picture, it turns out that two of the problems do not really arise and the third is not really problematic. I then suggest that my rescue of Augustine may rescue other prominent friends of DDS as well.

One central claim of orthodox Christianity is that in Jesus of Nazareth, God became man. On Chalcedonian orthodoxy, this involves one person, God the Son, having two natures, divine and human. If He does, one person has two properties, deity and humanity. But the Incarnation also involves concrete objects, God the Son (GS), Jesus’s human body (B) and—I will assume—Jesus’s human soul (S). If God becomes human, GS, B and S somehow become one thing. It would be good to have a metaphysical account of their oneness. I have suggested one. Thomas Senor has criticized my suggestion. I now reply to his case.

Anselm's "Cur Deus" Homo argues that only by the Incarnation can God save humanity. This seems to sit ill with the claim that God is omnipotent and absolutely free, for this entails that God could save humanity in other ways. I show that features of Anselm's concept of God and treatment of necessity make the claim that the Incarnation is a necessary means of salvation problematic. I then show that for Anselm, all conditions which make the Incarnation necessary for human salvation stem from God's nature and prior choices. If so, the Incarnation's necessity restricts neither God's freedom nor His power. For that the Incarnation is necessary given God's actual choices does not entail that it would have been necessary had God made other choices, or that God could not have made choices which would have made the Incarnation non-necessary.