Some theo-geeks out there may be aware of the continental theological megaclash between Brunner and Barth in the 20th century over the place of "natural theology" in coming to a knowledge of God. Now what is meant by natural theology is coming to a knowledge of God without special revelation - to form a view of God only form nature and reasoning. Brunner advocated some form of this...Barth just yelled NEIN! A friend of mine and I were kicking it around a bit through e-mail and I found his thoughts clear and helpful. B&B here refers to Brunner and Barth. Emphasis is mine...
I couldn't work in one important criticism of B&B's language: they use the terms natural revelation, natural theology, and natural religion interchangeably. I would use these terms to refer to different ideas and I think B&B use them to refer to different things....which makes B&B much harder to understand!
If God reveals himself cosmologically (in creation) , anthropologically (in humans), and Scripturally, the non-Scriptural means we call natural revelation. Natural theology we could then define as any enterprise that places what we know about God from natural revelation on par with (above or foundational to) what know about God through Scripture. I accept natural revelation; I reject natural theology.
Biblical theology or let's just say theology takes Scripture as the starting point for knowledge of God and allows natural revelation a secondary and peripheral place. We can think about God through natural revelation because we, though still in a fallen and thus humble state, can examine natural revelation in light of God's definitive self-revelation (Jesus in Scripture). When we approach non-believers then with theistic arguments we are recognizing two things: (1) that belief in god is not equivalent to belief in God (Ex 20.2-3 & John 20.28), and any knowledge of God that takes natural revelation as the normalizing knowledge of god is idolatry. However, (2) those in whom the Spirit works will begin to recognize Him in his handiwork and when they hear true knowledge of God, in whatever form it has come to them, they will yield to it.
In other words, God reveals himself through natural revelation (transmitters of his Glory), but the receivers (our knowledge of God through them) are broken. God's megaphone to the world falls on deaf ears. Actually, no, God's natural revelation falls on twisted ears that turn knowledge of God into gods of our own design. We justify our existence through them, though they come to dominate us. Without the Spirit speaking through the lens of Scripture all knowledge of God is idolatry. We thus stand condemned. When we take the Scripture as our starting point we can use natural revelation as a secondary form of knowledge of God. Some in whom the Spirit is at work will begin to recognize God through natural revelation, but we are people groping in the dark. God might (may it be so!) use natural revelation to destroy false idols, to make us uncomfortable in our captivity to them, to prod us, and to prepare the way for true knowledge of Himself.
So, yea, I agree! Natural revelation has a place in evangelism: a pointer to our foundation, light, shepherd and sum of all things, King Jesus...
Back to work...