When I came in the course of reading the Summa Theologica to the discussion of transubstantiation in the Eucharist, I realized something about the nature of Catholic theology. I found St. Thomas' explanation of this subject to be either absurd or - more likely - incomprehensible. But does my inability to grasp his explanation mean that the doctrine is false? By no means. The doctrine is true regardless of my ability understand it, and - more to the point of the present post - it is true regardless of my ability to understand the explanation by St. Thomas. It is true regardless of whether he was able to explain it in a fashion that I could have grasped.
And so I realized that Catholic theology is different than Protestant systematic theology in a significant way. Catholic theology is an attempt to make sense out of the truth: to explain it in comprehensible terms. This is one reason, it seems to me, why modern Catholic theology can differ so dramatically from (for example) the Scholastic attempts, and yet still be entirely orthodox.
Maybe that sounds dumb, or trivially obvious to brighter wits than mine or to life-long Catholics. But for this convert it was something of an epiphany. Because this is not how theology is done in the circles whence I came. Among Protestants (at least of my old stripe) theology is primarily "systematic" - that is, it consists of systematizing the Bible by collating various related verses in order to present what the Bible teaches on some given subject(s) or other. This is rather different from the Catholic model of explaining the Faith, but perhaps the difference makes sense. For the Protestant there is no rule of faith except the Bible, and so if you want to know what the truth is on a given subject, you must resort to ... collating the various verses that seem to relate to it: in other words, systematizing them.
Now whereas the Catholic theologian attempts to explain the Faith, the Protestant theologian's task seems to be more along the lines of (so to speak) defining the faith. What I mean is that since the Bible is "raw material" that doesn't exactly present its doctrine in a systematic fashion, that becomes a primary task of the theologian. The problem is, of course, that different theologians will differ on how things ought to be systematized. They will select different verses and passages as being of greater or lesser importance; they will declare one passage rather than another to be the keystone by which other verses ought to be understood; etc. The consequence is that "the faith" - meaning the system of doctrine - that they find in the Bible will vary considerably, depending upon the personal commitments of the theologians (are they Calvinist? Methodist? Anglican? Lutheran?).
In contrast you have Catholic theologians, who agree (presuming that they are orthodox) on the content of the Faith but who sometimes disagree on how to explain it. Thus you may have the theology of St. Thomas on the one hand, and you can have (for example) the theology of Cardinal Ratzinger/Pope Benedict on the other. Both are orthodox, and yet their theologies are dramatically different. I think that at least partly this can be explained on the basis of their different audiences. St. Thomas wrote for new students of scholastic theology; the Pope writes for 20th/21st century men. How their audiences think about things vary wildly; consequently how the two theologians present the faith to them also must be very different.
I was inspired to write about this subject by something the Crimson Catholic wrote today. It wasn't the primary purpose of his post, which has to do with differences between Byzantine and Latin theology, but in the course of it he said this:
In that regard, ISTM that the whole West (e.g., Ambrose, Hilary, Simplicianus, Jerome) followed Origen in method but not conclusions, examining the applicability of philosophical concepts to Christianity but also being willing to admit where the concepts were inadequate. If they reached a wrong dogmatic conclusion, rather than discarding the method entirely, the West was content to point out that they had made an error or taken some particular idea too far. In other words, if some philosophical approach reached a wrong conclusion, they were content to discard the approach. Because they weren't married to this one notion of philosophical knowledge, they could be eclectic in philosophy. That versatility, perhaps best exemplified by Augustine, characterized Western Christian thought and (I would argue) Western scientific thought all the way to the present day.Exactly! Or rather - this is exactly the sort of thing I mean. Dogmatic authority is distinct from philosophical authority. So the terms on which St. Thomas described the Faith - a scholastic, Aristotelian framework - can differ from the terms employed by Ratzinger (I hope it's fair to describe them summarily as philosophically modern - whether that is correct or not, it seems very clear to me that apart from some Thomoistic sympathies, Ratzinger's philosophical framework is emphatically not Thomistic).
What that enabled theologically was exposition of dogma. The theological conclusions had authority, so the Fathers were authorities regarding their conclusions, but like Aristotle with Plato, their philosophical explanations could be criticized and improved, opening the possibility of development. Hence, you could have disputations with authorities; even respected authorities were not immune to dialectical criticism. There was a Glossa Ordinaria; there were commentaries on the Sentences. In the case of theological authorities (like Scripture or the Pope), there was still utility in theological method in terms of conceptual improvement of one's own understanding, effectively giving more clarity or effect to the theological authority. ... In short, there was a gap between how something was examined qua theological authority and how it was examined qua philosophical authority, and the philosophical understanding was always revisable even if the fact of the dogmatic authority was not, much like the way one can revise a scientific explanation without changing the fact of the experimental data. Note that this is a separate issue from the formality of dogmatic authority addressed by the canonists; the interaction (and confusion) of those concepts is a whole 'nother can of worms.
Now I think it's likely that some Protestants suppose that the philosophic framework used by Catholic theologians cannot change: so that some of them might suppose that the Vatican II/post-Vatican II Church has broken with the past (as Turretinfan suggested in discussion) because the way that the Church explains the Faith has changed in some ways. No. The Faith has not changed. It is the same. The language has changed, and in some cases the understanding of some things may have advanced, and the way that the Faith is explained may be different, but the Faith itself is the same. Failure to understand these things is fundamentally a failure to understand Catholic theology and its relationship to the Catholic Faith.
Perhaps it is understandable in a certain fashion when they make this mistake, because conservative Protestant theology has (again, in the tradition of which I was part at least) a rather rigidly specified philosophical outlook. You have to get your theology from the Bible; you have to use a particular hermeneutic (grammatical-historical) when getting it from the Bible. When you read a theology, you are reading someone's attempt at spelling out what he thinks the teaching of the Bible is. But you can't approach Catholic theology like that. Catholic theology doesn't define the Faith in the way that we might say that Protestant theologies "define the faith". Catholic theology explains the Faith. Some explanations are better than others, and some explanations may be better suited to one era than another. In either case, the Faith itself remains unchanged.