What is authoritative? Sola Scriptura. So reason can help understand Torah but not override it. It is the major theme of the Middle Ages to find the right balance between Reason and Revelation. But when it come down to a direct conflict, the actual words of God in the Five Books of Moses and the Prophets must take precedent over the faulty and fallible reason of man. And what are prophets is not open. The word of God has not become irrelevant as time ha gone on. Nor have we advanced beyond God.
We need the Gemara to derive and understand the words of Torah, but not override them.
