The philosophy of religion comprises any philosophical discussion of questions arising from religion. This has primarily consisted in the clarification and critical evaluation of fundamental beliefs and concepts from one or another religious tradition. Major issues of concern in the philosophy of religion include arguments for and against the existence of God, problems about the attributes of God, the problem of evil, and the epistemology of religious belief.
Of arguments for the existence of God, the most prominent ones can be assigned to four types. First, cosmological arguments, which go back to Plato and Aristotle, explain the existence of the universe by reference to a being on whom all else depends for its existence. Second, teleological arguments seek to explain adaptation in the world, for example, the way organisms have structures adapted to their needs, by positing an intelligent designer of the world. Third, ontological arguments, first introduced by Anselm, focus on the concept of a perfect being and argue that it is incoherent to deny that such a being exists. Finally, moral arguments maintain that objective moral statuses, distinctions or principles presuppose a divine being as the locus of their objectivity.
Discussions of the attributes of God have focused on omniscience and omnipotence. These raise various problems, for example, whether complete divine foreknowledge of human actions is compatible with human free will. Moreover, these attributes, together with God’s perfect goodness give rise to the problem of evil. If God is all-powerful, all-knowing and perfectly good, how can there be wickedness, suffering and other undesirable states of affairs in the world? This problem has been repeatedly discussed from ancient times to the present.
The epistemology of religious belief has to do with the questions of what is the proper approach to the assessment of religious belief (for rationality, justification, or whatever) and with the carrying out of such assessments. Much of the discussion has turned on the contrast between the roles of human reason and God’s revelation to us. A variety of views have been held on this. Many, such as Aquinas, have tried to forge a synthesis of the two; Kant and his followers have sought to ground religion solely on reason; others, most notably Kierkegaard, have held that the subjecting of religious belief to rational scrutiny is subversive of true religious faith. Recently, a group of ‘Reformed epistemologists’ (so-called because of the heavy influence of the Reformed theology of Calvin and his followers on their thinking) has attacked ‘evidentialism’ and has argued that religious beliefs can be rationally justified even if one has no reasons or evidence for them.
Ethical Monism and The Problem of Evil