I sometimes wonder whether there are traditionalists in the Church who consider Thomism (or some other philosophy) to be The Philosophy of the Church. I’m not a traditionalist per se, I suppose, but if I remember things correctly around about the time of my introduction to the thought of St Thomas, I think I probably wondered whether such a thing might be truly said. In Fides et Ratio §76, Pope John Paul II suggests that the idea is misguided.
A second stance adopted by philosophy is often designated as Christian philosophy. In itself, the term is valid, but it should not be misunderstood: it in no way intends to suggest that there is an official philosophy of the Church, since the faith as such is not a philosophy. [Italics in original; bold added]
I think that’s an excellent way to look at it. This doesn’t mean that the truths discovered by philosophy are invalid, but rather that it’s the Church’s unique mission to proclaim the truths of faith and morals. Not all truths are within Her purview. She is not a schoolmarm to tutor us in geography or marine biology; She proclaims the truths related to our salvation. There is some overlap with philosophy, since some truths that God has revealed may also be known by means of reason, as St Thomas writes:
Even as regards those truths about God which human reason could have discovered, it was necessary that man should be taught by a divine revelation; because the truth about God such as reason could discover, would only be known by a few, and that after a long time, and with the admixture of many errors. [ST I q1 a1]
But this overlap doesn’t imply a demand for an official Christian Philosophy.