Two terms have become widespread for referring to the theological discipline dealing with Christian beliefs. The first is ‘dogmatics’ (or ‘dogmatic theology’) and is used especially but not exclusively by Catholics. The second is ‘systematics’ (or ‘systematic theology’) and is a term used especially but not exclusively by Protestants. The former term stresses the beliefs, the ‘dogmas’ that are being examined. The latter term stresses the systematic approach to the study of those beliefs. It is the term I wish to dwell on here for a moment.

What is systematic about systematic theology? Well, first of all it is systematic in the sense that it approaches its material systematically. It deals (usually) first with God, then with creation, then with the fall, then with redemption, the church, sacraments, etc, etc. However, it is also systematic in the sense that it tries to systematise the material in such a way that the inner connection between the various beliefs it studies becomes clear. For those beliefs are not simply a rag-bag of disconnected doctrines. There is an inner unity between them and one does not understand them fully if one cannot see that inner unity.

Now this unity can be brought out in several ways. One way is to show how they are connected to the actions of each of the three divine persons that make up what Christians call the Trinity. This is the approach adopted by the creeds, which speak of creation by God the Father, redemption by God the Son and the creation of the Church and the sanctification of the individual by God the Holy Spirit. This combines taking the Trinity as one's basic framework with a historical, narrative approach: telling the story of what God has done. Another way of bringing out the inner unity of the various beliefs that make up the Christian faith is to take one or more key ideas that are rooted in that faith and show how that idea or those ideas form a link between Christian beliefs. Thus the Reformed theologian Karl Barth took as his central idea ‘the Word’, and went on to show how the entire Christian faith is a response to the work and revelation of the Word in its various forms.