Metaphysical issues
The idea of God
The claim that there is a God raises metaphysical questions about the nature of reality and existence. In general, it can be said that there is not one concept of God but many, even among monotheistic traditions. The Abrahamic religions are theistic; God is both the creator of the world and the one who sustains it. Theism, with its equal stress on divine transcendence of the universe and immanence within it, constitutes a somewhat uneasy conceptual midpoint between deism and pantheism. Deist conceptions of the divine see God as the creator of a universe that continues to exist, without his intervention, under the physical impulses that he first imparted to it. In pantheism, God is identified with the universe as a whole. Theism itself has numerous subvarieties, such as occasionalism, which holds that the only real cause in the universe is God; thus, all other causes are simply signs of coincidence and conjunction between kinds of events occurring within the created order. For example, heat is not what causes the water in a teakettle to boil but is simply what uniformly occurs before the water boils. God himself is the cause of the boiling.
An important object of metaphysical reflection is God’s nature, or the properties of that nature. Is God simple or complex? If omniscience, omnipotence, and beauty are part of the divine perfection, what exactly are these properties? Is timeless eternity part of God’s perfection? Can an omnipotent being will that there be a four-sided triangle or change the past? Does an omniscient being know the future actions of free agents? (If so, how can they be free?) Does an omniscient being who is timelessly eternal know what time it is now?
God and the universe
Whatever may have been the influence of Classical philosophy on the Abrahamic religions, they have not, in general, accepted the Greek idea of the eternity of matter but have stressed the contingency of the universe as the free creation of God. It has been argued, most notably and influentially by Aquinas, that neither the eternity of matter nor the doctrine of creation can be established by reason alone; thus, the belief that the universe is not eternal and was created by God must be derived from revelation. Some, including Augustine, have claimed that God created the universe from a standpoint outside time; others claim that God, like the universe, is in time.
It is at points such as these in the philosophy of religion that philosophical arguments have less to do with establishing the truth of some proposition and more to do with working out a consistent and intelligible account of religious doctrine. At least since Augustine, philosophers in the Abrahamic religions have seen one of their tasks to be the achievement of a greater understanding of their own faith. They have examined the logical consequences of religious doctrines and sought to establish their consistency with the consequences of other beliefs, as illustrated in the remainder of this section.
God and human action
Philosophical reflection on the nature of God has typically assumed that God is the sum of perfection and is omnipotent and omniscient. Questions have arisen not only about the exact meaning of these claims but also about their consistency with widespread beliefs about human beings, chiefly the belief that they usually act freely and responsibly and should be held accountable for their actions. If God, being omniscient, knows the future, then God presumably knows what each person will do in the future. But if these actions are known by God, how can the person be free not to do them? And if the person is not free not to do them, how can he be held accountable for what he does? Even more difficult, perhaps, is the question: If God is omnipotent and exercises providential control over his creation, how can people be other than puppets?
Various strategies have been devised to overcome or to diminish the force of such difficulties. It has been supposed, for example, that God is outside time and so does not, strictly speaking, know anything beforehand. It has also been suggested that God does not know what humans will freely do before they actually do it. Some thinkers have drawn a distinction between the first cause of all that happens, which is God, and secondary causes, including humans and other creatures. And some philosophers of religion have been content with a conception of human freedom that is consistent with causal determinism, the view that all events and choices are determined by previously existing causes. According to them, an action is free if it is voluntary and uncoerced, and an action can be voluntary and uncoerced even though it is causally determined. These issues remain the subject of vigorous debate among contemporary philosophers.
The soul and immortality
The belief in life after death, which is maintained by each of the Abrahamic religions, raises the metaphysical question of how the human person is to be defined. Some form of mind-body dualism, whether Platonic or Cartesian, in which the mind or soul survives the death of the body, has been favoured by many theologians. Others have claimed that some version of physicalism or materialism is most consistent with scriptural ideas about the resurrection of the body. The former group has a tendency to disparage or downplay the importance of embodiment; the latter group, however, faces the problem of giving an account of the continuity of the person across the temporal gap between bodily death and bodily resurrection.
Religion and morality
Another concern of philosophers of religion is whether morality is dependent upon religion or is independent of it. Among those who take the former view, some say that morality depends upon religion in the way in which eating depends upon having an appetite: Religion provides the motivation that makes people behave morally. To prove this, however, it would be necessary to determine whether the behaviour of religious people is generally morally superior to that of nonreligious people. Others hold that morality depends on religion because the very idea of morality makes sense only if there is a God who sets objective standards or who will reward and punish people in the life to come. Otherwise, it is claimed, morality is a matter either of individual preference or of cultural or social convention.
Many of those who believe that morality is independent of religion have claimed that moral truths can be adequately discerned through reason, conscience, or moral intuition. In this connection it is worth noting that those who believe that religion is the basis of morality face the following dilemma: If the commands issued by God are morally obligatory, then that is because either: (1) they express independently justified moral values, or (2) God’s commands are necessarily morally good. If alternative 1 is true, then morality is independent of religion. If alternative 2 is true, then what is morally good seems to depend implausibly on God’s whim: if God commanded the torture of human infants, then it would be morally good to torture human infants. But this is absurd. This problem was first raised by Plato in his dialogue Euthyphro.
According to another perspective, derived from Kant, not only is it not the case that morality depends on religion, but in fact the reverse is true. As discussed above, in the Kantian tradition, the existence of God and the immortality of the soul are “postulates” of practical reason, or rational conditions of willing to bring about the highest good. Alternatively, they are conditions of adhering strictly to the moral law, which demands that one perform morally right acts only because they are right and not for any other reason, such as the goodness or badness of their consequences. Only in an eternal afterlife ordered by God would such perfection be possible.
The problem of evil
Perhaps the most difficult issue concerning the relation between morality and belief in God is the problem of evil. If God exists and is omnipotent and perfectly good, why does God allow horrendous evils such as the Holocaust? Why is any evil at all allowed by the divine? The problem is of ancient origins and has long been discussed by philosophers and theologians in the Abrahamic religions in relation to the Fall of Man—the expulsion, whether literal or metaphorical, of Adam and Eve from the Garden of Eden.
Few (if any) philosophers and theologians have been prepared to claim, with Leibniz, that the existing world is the best of all possible worlds. If it were not, Leibniz argued, what sufficient reason would God have had to create it? Apart from Leibniz’s view, three positive strategies have been developed. One stresses the importance of free will in accounting for moral evil (resulting from free human actions) as opposed to natural evil (resulting from natural events such as earthquakes and plagues); it argues that a world in which people act freely, albeit sometimes in an evil way, is to be preferred to a world of automata who do only what is right. Another strategy stresses the idea that some evils are a logical precondition for the existence of certain goods. The virtues of compassion, patience, and forgiveness, for example, can be developed only in response to certain needs or weaknesses. A world that contains these goods is better than one in which their exercise and development is impossible. The third approach emphasizes the “cognitive distance” between human understanding and God’s will, noting that humans cannot know in detail what the justification of God’s permission of evil might be. It is possible, of course, to combine these three positions, or elements of them, in attempting to offer an overall response to the problem of evil.
Some thinkers have approached evil, or certain evils, from the opposite direction. They have argued not that evil presents an overwhelming problem for theism but that it provides an argument for a life after death in which the injustices and inequities of the present life are remedied.