We may contrast this doctrine of the Trinity with Plato’s thought by calling attention to the fact that for Augustine the Trinity furnished the basis of the principles of unity and diversity in human knowledge. In other words the Trinity is for Augustine as for all orthodox Christians a conception without which knowledge were impossible to man. That there is plurality which man must seek to relate to some underlying unity, is patent to all men. From the earliest dawn of reflective thinking it has been the effort of man to find unity in multiplicity. But the difficulties that meet one when trying to speculate upon the question of unity and plurality are that if one begins with an ultimate plurality in the world, or we may say by regarding plurality as ultimate, there is no way of ever coming to an equally fundamental unity. On the other hand, if one should begin with the assumption of an ultimate abstract, impersonal unity, one cannot account for the fact of plurality. No system of thought can escape this dilemma. No system of thought has escaped this dilemma. Many systems of thought have denied one of the horns of the dilemma, but all that they have accomplished by doing this is to find relief in the policy of the ostrich.
What Augustine and all theistic thinkers after him have done is to say that in God, and more specifically in the triune God, lies the solution of this difficulty.
– Cornelius Van Til, A Survey of Christian Epistemology p. 47