I do not believe in "open revelation" as it is commonly known, I believe we have what we are supposed to have and one day God will speak again, but there will be no ambiguity. The interesting thing about the "devolving"  discussion is that I believe Adam was created perfectly, and every since the fall man and society has been sliding into chaos, in spite of what the progressives may say. Sure man grows in intellect and knowledge, but all knowledge (including logic and reason are created by God), and interesting debate on this subject is one between Greg Bahnsen and Gordon Stein, you can find it on youtube. It was from back in the 80's and the audio is challenging, but listenable. https://www.youtube.com/watch?v=anGAazNCfdY