In the Catholic ‘Encyclopedia of Theoloy’ edited by Karl Rhaner, there is a three-and-a-half page article under ‘God’ called ‘II. Knowability of God’ written by Eberhard Simons. He cites three passages, namely, Romans 1:18-21, 2:14ff., and Wisdom 13:1ff. Wisdom is not reckoned to be part of Holy Scripture in Calvinistic circles. However, Simons explains that the Wisdom passage
“affirms that God may be known from the greatness and beauty of
visible good things, as Lord of all creation. Men’s failure to
acknowledge God as Lord of creation is understandable but inexcusable.
Paul writes in the same vein in Rom. 1:18ff.” Page 564 (quoting those verses in
full, as do you).
The third text Simons uses is Romans 2:14-15. It reads,
“Indeed, when Gentiles, who do not have the law, do by nature things
required by the law, they are a law for themselves, even though they
do not have the law, since they show that the requirements of the law
are written on their hearts, their consciences also bearing witness,
and their thoughts now accusing, now even defending them” (N.I.V. 1987
The point is made that the knowability of God
“is seen to be inseparable from that of the proof of the existence of
God, but not identical with it. It has the prior task of defining the
framework within which alone a rational proof of the existence of God
can be possible.”
In all that is said there regarding biblical reasons, and if the Wisdom passage is as explained, all Calvinistic groups that I know of would agree. They, too, use that additional section of Romans 2:14-15 in conjunction with 1:18-20, so it’s hardly worth reiterating the same points they make. There is agreement that all humanity is accountable before God, their Maker, because there is no excuse for anyone claiming God is unknowable.
Then Simons makes an important point regarding the two Romans passages, with which Calvinistic groups would similarly agree. The way the conscience of pagans and their words of self-accusation or excuse testify to the law written in their hearts,
“according to which they act by nature, we have here a clear
indication of the universal knowability of God. But the knowledge is
hardly meant as theoretical and conceptual. It is to grow out of man’s
conscience in his contact with the things of this world, which is a
sort of medium through which it is obviously discernible. Being a
practical and existential knowledge of God, it is not threatened by
stupidity or deficiencies on the intellectual or rational level, but
by the moral attitude, the refusal of truth, injustice. Whatever be
the exact translation one adopts for these passages, one must be
careful not to read into them philosophical principles which cannot be
intended [emphasis mine]. The fact that they affirm that the godhead
of God appears and is obvious through the medium of the created world
need not be taken to mean an indirect knowledge of God through
causality or deduction.”
My Presbyterian Line Manager rejoiced at pointing out to me, when we were at gatherings of the mentally handicapped under the care of the Church of Scotland social services we worked for, that many of the clients were believers in God. Occasionally, some would even speak, in their own simple words, of their faith in Christ. No philosophical points had ever come to bear on their stance. They had not been indoctrinated with any particular ‘type’ of religion; they simply believed in God and knew they could trust Jesus, and nobody ever pressed them into speaking of that. They were happy to volunteer uncomplicated expressions of faith. Indeed, a child-like faith is never to be sneered at, for “From the lips of children and infants you have ordained praise” (Psalm 8:2 as quoted by Jesus in Matthew 21:16). And Jesus added, “I thank thee, O Father, Lord of heaven and earth, because thou hast hid these things from the wise and prudent, and hast revealed them unto babes” (Matthew 11:25).
As a Calvinist, I would add those three scriptures to the biblical basis for believing that some sense of God exists in humans, right from infancy.