Michael Sudduth's book "The Reformed Objection to Natural Theology" traces noted thinkers in the Reformed Tradition and how they've responded to natural theology. It is a helpful book that can be read with benefit. In the book Sudduth considers various ways Reformed thinkers have sought to argue against the necessity of natural theology. Interestingly, Michael Sudduth recently posted an open letter explaining his conversion from Protestant Christianity to Hinduism and the worship of Krishna. This worldview makes more sense to Sudduth than what he had been presented in the Protestant world. I should note that Michael Sudduth read my manuscript for "Reason and Worldviews" and gave me feedback about my chapter on Alvin Plantinga.
Alvin Plantinga is perhaps the best known contemporary thinker who has written in support of the Reformed Objection to Natural Theology (most philosopher of religion readers contain an essay by Plantinga with that title). The so called "Reformed Objection to Natural Theology" is the claim that natural theology is at best helpful although unneeded, and at worst a distraction and elevation of "human reason" against the Bible. Natural theology gives argument for God's existence, but these arguments are circular (assuming Biblical revelation) and often simply unsound. By way of contrast, all humans are given the "sensus divinitatis" which is an inner sense of God. In their sinful condition, humans suppress this sense and live in unbelief.
Before we can even begin to discuss what Biblical revelation says about natural theology, we need to ask why there is a need for Biblical revelation? Why believe that all persons have a "sensus divinitatis" that they are suppressing? If the answer involves an argument that does not assume the Bible then it is a natural theology argument and the need for natural theology is affirmed. If the argument assumes the Bible then it is circular and fallacious. I'll call this the "dilemma of natural theology."
To support this "Reformed Objection," proponents will appeal to theologians like Calvin or Hodge. While these thinkers did have a high regard for theistic proofs, they also said these are insufficient. However, their insufficiency is in respect to salvation, not with respect to the culpability of unbelief. As one reads these thinkers one often finds that they affirm the culpability of unbelief with regards to the general revelation of God's existence.
The claim is that the Bible teaches there is a sensus divinitatis, a sense of the divine, in all persons. People reject this sense and are therefore guilty. Let's say the Bible does teach this, how would we know we should believe the Bible? Inevitably we will end up having to give a proof for God's existence besides the appeal to the sensus divinitatis. If we simply appeal to the sensus divinitatis to support the Bible, and then prove the validity of the Bible by appealing to the sensus divinitatis, we are arguing in a circle. To avoid the circule, we must rely on natural theology.
Furthermore, what is the content of the sensus divinitatis? A mere sense of the other? Could this other be Zeus or Krishna? Is it actual theism? Biblical theism? Since the claim is that there is a rejection of the God of the Bible, it must be Biblical theism. Yet, people aren't actually able to give an account of this sense with that content. It generally stays at "higher power" or "sense of the other." This is not theism, and not enough to hold persons accountable for rejecting theism. Conceivably, persons could have this sense and consistently adopt any number of views of the divine, and yet the Bible calls these incorrect.
For the sake of argument, let's say notable Reformed thinkers deny that general revelation revelas God. We can nevertheless appeal to the Westminster Confession which affirms in Chapter 1.1 that the light of nature, and works of creation and providence, do so clearly reveal the existence of God that unbelief is without excuse. It takes the focus away from soteriology and instead places it on the glory of God, affirming in the Shorter Catechism that man's chief end is to glorify God.
Apart from the question of "what counts as THE Reformed view," we are faced as individuals with the question of meaning. What is the meaningful view? Any view which assumes its own truth is begging the question and offering circular reasoning. Any worldview can do this. Why should we accept such a worldview?
Returning to Michael Sudduth, can humans know whether Christianity or Hinduism is true? Those in the "Reformed Objection" camp will fall back on soteriology to make their case. They will argue that those who are elect will respond to the true message. Again, this simply begs the question. Why believe this account? It seems to me that Sudduth can give a mirror argument about a sensus divinitatis for his version of Hinduism. Similarly, he can give a mirror argument about feeling conviction while reading the Bhagavad Gita. My point is simply that natural theology, beginning with the critical analysis of basic beliefs, is necessary.
Soteriology, the doctrine of salvation, assumes that humans are fallen and need to be saved. To be fallen means that humans are culpable of something. The Reformed Objection must explain what humans are culpable of and why this requires salvation. If they appeal to the Bible, which is redemptive revelation, they have given us circular reasoning. Any sound argument must be in the realm of "natural theology" by showing the clarity of general revelation.
The Reformed Objection to Natural Theology should encourage us to avoid circular reasoning and instead ask whether unbelief is culpable, and if so can this be shown.