John Calvin on the Ancients Ability to Divine Truth

I’ve been reading the book  God and the Cosmos: Divine Activity in Space, Time and History  by Harry Lee Poe and Jimmy H. Davis and in their introduction they used the following quote from John Calvin:

If we reflect that the Spirit of God is the only fountain of truth, we will be careful, as we would avoid offering insult to him, not to reject or condemn truth wherever it appears. In despising the gifts, we insult the Giver.

I appreciated the point that the authors were trying to make about the truths that man can gain from the study of the natural world but I wanted to be sure that this quote was being used in the context that Calvin intended  so I looked up the full section. This quote comes from Calvin’s Institutes of Christian Religion published in 1536.  Below are sections 2.2.236 and 2.2.237 which can be found here.  What we see in this quote is Calvin reflecting on common grace or the ability of each person made in the image of God to display intelligence in some area and be able to discern truth in this world even if that person may not attribute that truth to the correct source.

Next come manual and liberal arts, in learning which, as all have some degree of aptitude, the full force of human acuteness is displayed. But though all are not equally able to learn all the arts, we have sufficient evidence of a common capacity in the fact, that there is scarcely an individual who does not display intelligence in some particular art. And this capacity extends not merely to the learning of the art, but to the devising of something new, or the improving of what had been previously learned. This led Plato to adopt the erroneous idea, that such knowledge was nothing but recollection.  So cogently does it oblige us to acknowledge that its principle is naturally implanted in the human mind. But while these proofs openly attest the fact of a universal reason and intelligence naturally implanted, this universality is of a kind which should lead every individual for himself to recognize it as a special gift of God. To this gratitude we have a sufficient call from the Creator himself, when, in the case of idiots, he shows what the endowments of the soul would be were it not pervaded with his light. Though natural to all, it is so in such a sense that it ought to be regarded as a gratuitous gift of his beneficence to each. Moreover, the invention, the methodical arrangement, and the more thorough and superior knowledge of the arts, being confined to a few individuals cannot be regarded as a solid proof of common shrewdness. Still, however, as they are bestowed indiscriminately on the good and the bad, they are justly classed among natural endowments.

Therefore, in reading profane authors, the admirable light of truth displayed in them should remind us, that the human mind, however much fallen and perverted from its original integrity, is still adorned and invested with admirable gifts from its Creator. If we reflect that the Spirit of God is the only fountain of truth, we will be careful, as we would avoid offering insult to him, not to reject or condemn truth wherever it appears. In despising the gifts, we insult the Giver. How, then, can we deny that truth must have beamed on those ancient lawgivers who arranged civil order and discipline with so much equity? Shall we say that the philosophers, in their exquisite researches and skillful description of nature, were blind? Shall we deny the possession of intellect to those who drew up rules for discourse, and taught us to speak in accordance with reason? Shall we say that those who, by the cultivation of the medical art, expended their industry in our behalf were only raving? What shall we say of the mathematical sciences? Shall we deem them to be the dreams of madmen? Nay, we cannot read the writings of the ancients on these subjects without the highest admiration; an admiration which their excellence will not allow us to withhold. But shall we deem anything to be noble and praiseworthy, without tracing it to the hand of God? Far from us be such ingratitude; an ingratitude not chargeable even on heathen poets, who acknowledged that philosophy and laws, and all useful arts were the inventions of the gods. Therefore, since it is manifest that men whom the Scriptures term carnal, are so acute and clear-sighted in the investigation of inferior things, their example should teach us how many gifts the Lord has left in possession of human nature, notwithstanding of its having been despoiled of the true good.