Francis Nigel Lee, Calvin on the Sciences, pp. 16-19:
All sinful men are enabled to understand something of God's common revelation through this sin-stained universe, by means of His common grace which they all receive, albeit in different degrees. Hence the development of the sciences is not the monopoly of Christians alone, for by God's common grace (operating through the primordial revelation in Eden, through later contact with the covenant people, and/or through God's general revelation in nature and conscience) even unbelievers are enabled to obtain some true insights into scientific truth, for "in regard to the constitution of this present life, no man is devoid of the light of reason" (Inst. II: 2:13), and "in every age there have been some who, under the guidance of nature, were all their lives devoted to virtue", so that "we ought to consider that, notwithstanding the corruption of our nature, there is some room for divine grace, such grace as, without purifying it, may lay it under internal restraint" (Inst. II:3:3).
Calvin correctly points out that "in the sad disorder which followed the fall of Adam, the whole of the world would have instantly been deranged, and all its parts would have failed, had not some hidden strength supported them" (Comm. on Rom. 8:19). This "hidden strength" supporting the world was obviously the Second Person of the Triune God, the pre-incarnate Christ, "the first-born of every creature" or "the substance or foundation of all things" (Comm. on Col. 1:15). He it was Who, as the promised Seed of the woman, sustained and in principle rejuvenated the cosmos even right after the fall and for ever since (Gen. 3:15f; Rom. 16:20), for "the Logos of God was not only the Source of life to all creatures, so that those which were not began to be, but...His life-giving power causes them to remain in their condition; for were it not that His continued inspiration gives vigour to the world, everything that lives would immediately decay, or be reduced to nothing" (Comm. on John 1:4).
Christ it is Who is "the light of the whole world;...out[side] of Christ there is not even a spark of true light...the fountain of all knowledge and wisdom is hidden in Him" (Comm. on John 8:12), for "the light which still dwells in corrupt nature consists chiefly of two parts; for, first, all men naturally possess some seed of religion; and secondly, the distinction between good and evil is engraven on their consciences...man especially was endued with an extraordinary gift of understanding; and though by his revolt he lost the light of understanding, yet he still sees and understands, so that what he naturally possesses from the grace of the Son of God is not entirely destroyed" (Comm. on John 1:5). "In this sense it is said (John 1:5), that 'the light shineth in darkness, and the darkness comprehended it not'; these words clearly expressing...that in the perverted and degenerate nature of man there are still some sparks which show that he is a rational animal, and differs from the brutes, inasmuch as he is endued with intelligence" (Inst. II:2:12).
Christ, then, is the root of common grace. Had it not been for His immanence in the universe right from its very creation onwards, and had it not been for His direct intervention (and His promise to heal the universe, Gen. 3:15f, cf. Rom. 8:19f.) right after the fall, man and his cosmos would right then have disintegrated, and even Cain and the Cainites would never have been born.
Now in respect of these very Cainites, Calvin has much to say on the subject of common grace. He stoutly insists that "with the evils which proceeded from the family of Cain, some good has been blended. For the invention of arts, and of other things which serve to the common use and convenience of life, is a gift of God by no means to be despised, and a faculty worthy of commendation. It is truly wonderful, that this race, which had most deeply fallen from integrity, should have excelled the rest of the posterity of Adam in rare endowments. I, however, understand Moses to have spoken expressly concerning those arts, as having been invented in the family of Cain, for the purpose of showing that he was not so accursed by the Lord but that He would still scatter some excellent gifts among his posterity...Moses, however, expressly celebrates the remaining benediction of God on that race, which otherwise would have been deemed void and barren of all good. Let us then know, that the sons of Cain, though deprived of the Spirit of regeneration, were yet endued with gifts of no despicable kind; just as the experience of all ages teaches us how widely the rays of divine light have shone on unbelieving nations, for the benefit of the present life; and we see, at the present time, that the excellent gifts of the Spirit are diffused through the whole human race. Moreover, the liberal arts and sciences have descended to us from the heathen. We are, indeed, compelled to acknowledge that we have received astronomy, and the other parts of philosophy, medicine, and the order of civil government from them. Nor is it to be doubted, that God has thus liberally enriched them with excellent favours that their impiety might have the less excuse" (Comm. on Gen. 4.20).
Calvin develops his doctrine of common grace in relation to the various sciences particularly in the second chapter of Book II of his Institutes. There he teaches, amongst other things, that "to charge the [fallen] intellect with perpetual blindness so as to leave it no intelligence of any description whatever, is repugnant not only to the Word of God, but to common experience", for "the human mind...is naturally influenced by love of truth" (II:2:12), especially with reference to "matters of policy and economy, [and] all mechanical arts and liberal studies", with the result that "we see that the minds of all men have impressions of civil order and honesty"(II:2:13).
It is, however, in the "manual and liberal arts" in which "the full force of human acuteness is displayed"; and although "all are not equally able to learn all the arts,...there is scarcely an individual who does not display intelligence in some particular art", which fact "should lead every individual for himself to recognize it is a special gift of God" (II:2:14).
It must not be forgotten, then, that "there are most excellent blessings which the Divine Spirit dispenses to whom He will for the common benefit of mankind", for indeed, God "fills, moves and invigorates all things by the virtue of the Spirit" (II:2:16). In the light of this profound truth, Calvin rhetorically asks: "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 descriptions 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 on 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 inventions of the gods. Therefore, since it is manifest that men whom the Scriptures term 'natural', 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" (II:2:15).
So, therefore, concludes Calvin, "let us not forget that...the knowledge of those things which are of the highest excellence in human life is said to be communicated to us by the Spirit" (II:2:16). For "in this diversity we can trace some remains of the divine image distinguishing the whole human race from other creatures" (II:2:17).