Traditionally, the 4-fold model of theology is accepted. The four are:
Biblical and Historical theologies provide the basis for systematic theology, and systematic theology provides the foundation for practical theology. (Some would add philosophical theology as another source for systematic theology).
Systematic theology can be broken down a number of ways. Here is one: –Theology Proper (study of God) -Anthropology (study of man) -Christology (study of Jesus) -Pneumatology (study of the Holy Spirit) -Soteriology (study of salvation) -Bibliology (study of the Bible) -Angeology (study of angels, demons, etc.) -Ecclesiology (study of the church) –Hamartiology (or theodicy… study of sin and suffering) -Eschatology (study of the last days).
From the foundation of these areas of systematic theology one comes up with Practical theology (which covers various areas of ministry such as homiletics, pastoral care, and liturgy). This would include missions.
What is the problem? As stated earlier… there is disunity in theology. From the standpoint of missions, part of this comes from the fact that those involved in missions are poorly grounded in theology, and tend to develop theology to justify what they are doing, rather than the other way around.
To be fair… this is understandable. After all, what branch of systematic theology clearly covers missions? None all that well. Clearly, soteriology and ecclesiology have some bearing on missions. Perhaps hamartiology and eschatology as well. Perhaps all of the branches have something to say. Yet in practice, often none of them deal with missions or missio deo (God’s Mission) in a systematic and integrated manner. Commonly, the Bible is brought in to justify missions or justify some specific methodology. This, of course, not theology. It is barely more than “proof-texting”. Missiologists (practical theologians in the area of missions) don’t have good material from systematic theology to draw from (as is often noted, John Calvin‘s magnum opus, “Institutes of the Christian Religion” did not have a section on missions. Things have not improved much since then).
Perhaps, Missions should not simply be an area of practical theological study. Perhaps missions should not be simply scattered topics within the broader topics within systematic theology. Perhaps Missiology should be a topic within systematic theology itself. Missiology should integrate biblical and historical (and perhaps philosophical) theologies.
Would this result in “better” mission methods? I am not sure… but I believe so. I believe the rather short-sighted methods utilized often draw from completely unsupportable theological stances. Still “good missions” (orthopraxy in missions) needs both sound theology and sound social sciences, so theology whose roots are limited to systematic theology would be too limited. But it is a start. We, I think, need to do both sides (theology and sociology) well and bring them together into dialogue.
For example, many missiologists encourage focus on quick conversions and spiritualistic methods targeting “unreached people groups.” Perhaps they are correct. Perhaps quick conversions is more important than discipleship. Perhaps spiritualistic methods should be the focus over development or social work. Perhaps unreached people groups should be the main focus. However, the justification for this is often Matthew 24:14 “And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end come.” Regardless of whether the methods described above our sound or not… there is NO justification for interpreting that verse that way. In fact, a systematic theological method would not not attempt to justify methods by prooftexting anyway.
I believe it is possible that a sound theological grounding for missions will make Christian missions more successful (successful in the eyes of God at least).