As a minor footnote to the past few posts on the Introduction to Christianity, I should note that the Ratzinger of 1968 does not know Aristotle well.  For example, he says on page 160:

Greek thought always regarded the many individual creatures, including the many individual human beings, only as individuals, arising out of the splitting up of the idea in matter.  The reproductions are thus always secondary; the real thing is the one and universal.  The Christian sees in man, not an individual, but a person; and it seems to me that this passage from individual to person contains the whole span of the transition from antiquity to Christianity, from Platonism to faith.

That the universal is more real is in fact a platonic notion, but Aristotle–surely to be included in “Greek thought”–emphatically denied this.  He said that the individual is more real.  To be fair, Aristotle did not dominate antiquity as Plato did, but given the major role his philosophy played in Boethius and in all of medieval theology, one would expect that he would get an honorable mention as an important thinker of antiquity.

At another point, on page 174, Ratzinger argues that one must approach a mystery by putting together statements that seem irreconcilable to reason but in fact are complementary:

The intellectual approach of modern physics may offer us more help here than Aristotelian philosophy was able to give.  Physicists know today that one can only talk about the structure of matter by approaching the subject from various angles.  They know that the position of the observer at any one time affects the results of his investigation of nature.  Why should we not be able to understand afresh, on this basis, that in the question of God we must not look, in the Aristotelian fashion, for an ultimate concept emcompassing the whole but must be prepared to find a multitude of aspects that depend on the position of the observer and that we can no longer survey as a whole but only accept alongside each other, without being able to say the final word on the subject?  We meet here the hidden interplay of faith and modern thought.  That present-day physicists are stepping outside the structure of Aristotelian logic and thinking in this way is surely an effect already of the new dimension that Christian theology has opened up, of its need to think in “complementarities”.

Aristotle does in fact, in subtle ways, approach difficult realities from various angles, and in fact he gives an explicit account of why matter is difficult to know.  But Thomas Aquinas offers an even clearer example of a pre-modern, Aristotelian theologian who already grasped this insight Ratzinger finds in modern physics.  For example, in his discussion of the union of divinity and humanity in Christ in chapter 11 of his Compendium, Aquinas explicitly says that we cannot find an all-encompassing explanation because this mystery exceeds reason, and then he goes on to lay out two seemingly opposed but in fact complementary ways to understand it.  It’s the exact procedure Ratzinger lays out.

More on this point soon.