It must, therefore, examine the different religions to find wherein each is complete or defective, true or false; how each may supply the defects of the other or prepare the way for a better; how each religion acts on the race which receives it, is adapted to that race, and to the region of the earth which it inhabits.

In this department, therefore, it connects itself with Comparative Geography, with universal history, and with ethics.
Finally, this department of Comparative Theology shows the relation of each partial religion to human civilization, and observes how each religion of the world is a step in the progress of humanity.

It shows that both the positive and negative side of a religion make it a preparation for a higher religion, and that the universal religion must root itself in the decaying soil of partial religions.

And in this sense Comparative Theology becomes the science of missions.
Such a work as this is evidently too great for a single mind.

Many students must co-operate, and that through many years, before it can be completed.