I am reading James Barr’s Biblical Faith and Natural Theology, which you can find here.
In the twentieth century, based on Protestant neo-orthodoxy, there was a tendency to discount the idea that nature tells us anything about God. Folks who thought this way had to deal with some passages in the early part of the letter to the Romans, for instance:
For since the creation of the world his invisible attributes – his eternal power and divine nature – have been clearly seen, because they are understood through what has been made. So people are without excuse (Romans 1:20 NET Bible).
For whenever the Gentiles, who do not have the law, do by nature the things required by the law, these who do not have the law are a law to themselves (Romans 2:14 NET Bible).
Many commentators have challenged the idea that these passages justify a natural theology independent of biblical revelation. Barr thought that there was a twentieth century prejudice against the notion of natural theology that made commentators go out of their way to discount it. And he thought that the assumption that natural theology had to be set apart from biblical revelation was wrong.
He said that some of these challenges amounted to the idea that in Romans Paul only means that people are without excuse when they break God’s law. Barr agrees that the inexcusableness of Jew and Gentile is Paul’s theme, but he asks whether the only makes sense. Why is a natural theology not possible based on Paul’s understanding that people know things from creation and nature?
Barr thought that when you looked at the argument in Romans and the Acts 17 speech on the Areopagus without prejudice they seem “strikingly complementary”.
Although Paul didn’t mention Greek philosophers in Romans, he used the term “nature” in the way Stoic philosophers used it. Judaism had already picked up on this use of nature. Barr cited examples from 4 Maccabees and Josephus. Philo spoke of the “law of nature” and made nature somewhat parallel to the Torah. So Paul, a Jew of Tarsus, unsurprisingly spoke of the authority of nature.
Acts 17 and Romans both speak of Gentiles as having knowledge from creation. Barr insisted that this was in line with Jewish and Hebrew thought. He said that, going forward in the lectures, he would argue that “the real source from which Christian natural theology sprang is Hebraic”.
Barr was a Hebrew Bible scholar more than a New Testament scholar, so this foray into the New Testament sets the stage for his main argument about natural theology before Christ. Tertullian asked what Athens and Jerusalem had in common. That question was renewed by Barth and his followers. But Barr wanted to show that the opposition between the two is something of a misunderstanding.
Jewish thinkers who wrote in Greek expressed their Jewish thoughts not only in Greek words but in the Greek thought-forms that were so very customary to them.
If therefore our researches were to make it seem that Paul or other NT authority was substantially dependent on categories of Greek popular philosophy for his thoughts and arguments we would not be troubled by this; it would count simply as a reality of the situation. For by arguing that Paul or any other NT writer is essentially Hebraic or Jewish in spirit and heritage we are not thereby making it more clear that he is opposed to natural theology; on the contrary we are making it more probable that he is sympathetic to it.