Theological realism typically involves three claims: that God exists independently of human beings (an ontological claim); that God can be known (an epistemological claim); and that God may be spoken about truthfully (a semantic claim). It therefore has features analogous to realist interpretations of other regions of discourse such as ethics and science. Theological realism can be distinguished from religious realism in that debate about the former arises from and draws upon the beliefs and doctrines of a particular religious tradition such as Christianity. The issues which arise in the debate about realism in Christian theology have analogues in some other religious traditions.
In the philosophical literature, religious realism is usually discussed in abstraction from particular doctrinal claims. Debate about religious realism may, for example, investigate the question as to whether God exists independently of human minds. Atheists agree with religious realists that ‘God exists’ has truth-apt content and can be construed realistically, but, unlike religious realists who believe they have sound arguments for God’s (probable) existence, they deny that it is true: the arguments are not sound, there is no God to be known, and hence religious discourse is systematically erroneous.
Theology is concerned with stating the content of Christian beliefs, so theologians who wish to defend a realist interpretation of them are likely to assume and appeal to core doctrines – such as the incarnation – that are philosophically controversial, if not implausible. For example, theologians are likely to want (with the church Fathers) to analyse ‘God exists’ so that it is consistent with its being true that ‘the Word of God, who is "of one substance" with the Father, assumed human flesh in Jesus Christ’. As a little reflection on this example shows, unlike in philosophical discussions of religious realism, it is difficult to tease out for separate analysis the ontological, epistemological and semantic aspects of the statement ‘God exists’ or to decide which should have priority in such an analysis.
However, contemporary discussions of realism in theology focus less on whether God exists than on other questions: What is the correct analysis of language about God?; Is it metaphorical, analogical or univocal? How does it refer? Does Christian doctrine itself refer to God or does it set out rules for using the language of prayer and worship that is addressed to God? How, and to what extent, may God be known, and what is the role of narrative, worship and devotional practice in that process? What account is to be given of judgements as to the truth and falsehood of particular theological statements? The most popular current analysis of Christian discourse about God construes it on analogy with scientific realism about unobservable entities, but there are significant theological difficulties with this approach.
Some Christians deny that God has any mind-independent existence but, rather than espouse atheism, they argue for versions of noncognitivism: the aim of Christian discourse is not to describe the world but to express the attitudes or feelings of those who use it. Wittgensteinian philosophy of religion – which holds that the meaning of a religious term is given by its use in a religious language game – is often, though controversially, interpreted along these lines (see Runzo 1993; Scott 2000; and Tessin and von der Ruhr 1995).