May it be that some things can be learned about God simply by observation
of the world? If I may make use of the Watchmaker analogy, once I
aknowledge that a maker exists I may infer simply by looking at the watch
that the maker has a certain knowledge of mechanics, an interest in
time-keeping, etc.. But there would be many other things which could not
be inferred. To know them I would have to meet the Watchmaker and he would
have to reveal them to me.
What is debated is whether the existence of the Watchmaker can properly be
inferred from simple observation of the watch.
I think that Rom 1 is indeed relevant. The line of argument through into
to chapter 2 seems to aim at removing from all people any excuse for their
rejection of God, and at establishing the universal sinfulness of the race.
That includes those (Gentiles) who were not privileged to have received
God's historical revelation to Israel. Paul's point in the longer run is
to develop the argument that Gentiles too can be saved, as Christ is the
counterpart to Adam (Rom 5-6).
But on what basis can they be held accountable for their rejection of one
who had not been revealed to them? Despite that they have not been the
recipients of that revelation which came through the Jewish people, they
are held accountable in view of what has been plainly visible to all people
in all places.
Whilst the text does not starkly insist that God's existence is properly
inferrable from the world around, it does say that certain qualities are
discernible. And it would need explaining how qualities could be inferred
to a being whose existence cannot be.
This is not independent natural theology because it asserts that a
sufficient knowledge of God can only come through special revelation, but
it accords some true and decisive content to general revelation