In contemporary English the word ‘theology’ means “the study of God.” Christian theology, then, is the study of God and related topics from a Christian religious perspective. Understood in this way, Christian theology is an academic discipline with a specific subject matter, much like biology (the study of life), or psychology (the study of the mind or soul), or anthropology (the study of humans and culture)—though the methods and subject matter of theology are considerably different from these other academic disciplines. In addition to understanding theology as a discipline, a particular theology may be understood as a specific theologian’s account of God or related topics.
There are several different sub-disciplines of Christian theology. Some of the main Christian theological sub-disciplines are described briefly below. There are also links below to pages with more detail on the various kinds of Christian theology.
Biblical theology is the sub-discipline of Christian theology that aims to understand and synthesize what scripture, or the Bible, tells us about God and other theological topics. As such, biblical theology is primarily distinguished from other types of theology by the methodology it uses to draw its conclusions. Specifically, the method of biblical theology exclusively focuses on the study and interpretation of scripture. Biblical theologians may focus on one part of scripture—e.g., the New Testament, or the Old Testament (i.e., the Hebrew Bible)—or they may take all of scripture as their source of theology.
Systematic theology is an integrative sub-discipline of Christian theology that aims to give a critical, coherent, balanced account of main topics in Christian belief and practice. The late theologian Stanley Grenz offers the following definition of systematic theology: “the reflection on, and the ordered articulation of, faith” (p. 1). Systematic theology itself is traditionally divided into the following sub-disciplines: revelation (i.e., the theology of scripture), theology (i.e., the doctrine of God), anthropology (i.e., the theology of human beings), hamartiology (i.e., the theology of human sinfulness), Christology (i.e., the theology of Jesus Christ), pneumatology (i.e., the theology of the Holy Spirit), soteriology (i.e., the theology of salvation), ecclesiology (i.e., the theology of the church), and eschatology (i.e., the theology of last things).
Historical theology is the branch of Christian theology that focuses on the biblical and systematic theology of theologians of the past. For example, study of the theology of Irenaeus, Apollinaris, Theodore of Mopsuestia, Pelagius, Saint Augustine, Saint Anselm, Abelard, Saint Thomas Aquinas, Martin Luther, John Calvin, Friedrich Schleiermacher, John Wesley, Karl Barth, Adolf von Harnack or any number of other historical theologians would count as part of the task of historical theology. See the Theologians page for links to important examples of historical theology.
Moral theology is the branch of Christian theology that addresses questions relating to how Christians ought to live. Topics of moral theology might include concrete ethical issues, such as whether abortion, the death penalty, and homosexual behavior are morally permissible; or what duties the church has with respect to the poor and homeless; or which sorts of specific activities make up a good Christian life (i.e., which activities are virtuous). However, moral theology might also address more abstract issues such as what makes an act right, wrong, good, or bad (e.g., God’s command or natural law); which principles ought to govern human activity in general (e.g., the great love commands); or what exactly is implied by the concepts of love and justice. What makes reflection on such abstract issues moral theology (as opposed to mere moral philosophy) is that the moral theologian includes scripture and historical theology in her methods.
Practical theology is the branch of Christian theology that addresses theological topics with immediate practical significance. For example, practical theology might include reflection on the spiritual disciplines that encourage Christian spiritual formation or sanctification, such as lectio divina, listening prayer, intercession, or fasting. Theological reflection on pursuing the Christian mission in today’s world, or pastoral counseling might also be tasks for practical theology.