Calvin on Twofold Knowledge
Calvin speaks of a twofold knowledge: knowledge of God prior to the fall, and knowledge of God after the fall. Prior to the fall, “man possessed freedom of the will, by which, if he chose, he was able to obtain eternal life.” He relates this freedom to the mind of man when he says, “At first every part of the soul was formed to rectitude. There was soundness of mind and freedom of will to choose good.” Speaking of the natural man’s knowledge after the fall, Calvin writes, “Although they are forced to acknowledge that there is some God, they, however, rob him of his glory by denying his power.” Interestingly, Calvin adds the possibility of the natural man pondering the true God against his will, “When they do think of God it is against their will; never approaching him without being dragged into his presence, and when there, instead of the voluntary fear flowing from reverence of the divine majesty, feeling only that forced and servile fear which divine judgment extorts…”
Natural Revelation & Natural Theology
Speaking more clearly to natural revelation in se, he writes:
[God’s] essence, indeed, is incomprehensible, utterly transcending all human thought; but on each of his works his glory is engraved in characters so bright, so distinct, and so illustrious, that none, however dull and illiterate, can plead ignorance as their excuse.
Muller, commenting on words such as these, says, “Calvin must argue in this way because he assumes the existence of natural revelation which in se is a true knowledge of God. If natural theology were impossible, idolatrous man would not be left without excuse.” Calvin offers a stronger, albeit still implicit, affirmation of natural theology:
In attestation of his wondrous wisdom, both the heavens and the earth present us with innumerable proofs, not only in those more recondite proofs which astronomy, medicine, and all natural sciences are designed to illustrate, but proofs which force themselves on the notice of the most illiterate peasant, who cannot open his eyes without beholding them.
Speaking of the means by which this natural theology becomes distorted in natural man, he says, “they cannot but know that these are proofs of his Godhead, and yet they inwardly suppress them.” Calvin also appears to understand a measure of natural theology common to both non-Christians and Christians when he writes, “I only wish to observe… that this method of investigating the divine perfections, by tracing the lineaments of his countenance as shadowed forth in the firmament and on the earth, is common both to those within and to those without the pale of the church.” Speaking to the theistic proofs, he says, “We see there is no need of a long and laborious train of argument in order to obtain proofs which illustrate and assert the divine majesty. The few which we have merely touched, show them to be so immediately within our reach in every quarter, that we can trace them with the eye, or point them with the finger.”
The State of Man’s Knowledge Before & After the Fall
Calvin hardly works out in detail a covenant of works between God and man according to man’s prelapsarian state. However, Calvin does outline the elements of that first covenant. Writing on Genesis 2:16, “Moses now teaches, that man was the governor of the world, with this exception, that he should, nevertheless, be subject to God.” Connecting Adam’s probation with his knowledge or theology, he says, “Therefore, abstinence from the fruit of one tree was a kind of first lesson in obedience, that man might know he had a Director and Lord of his life, on whose will he ought to depend, and in whose commands he ought to acquiesce.” Describing the state of man’s knowledge of God after the fall from Genesis 3:8, he writes, “Moses here relates nothing which does not remain in human nature, and may be clearly discerned at the present day. The difference between good and evil is engraven on the hearts of all, as Paul teaches, (Rom. ii. 15;) but all bury the disgrace of their vices under flimsy leaves, till God, by his voice, strikes inwardly their consciences.”
Calvin, therefore, acknowledges a difference not in natural theology in se between pre- and post-fall man, but in what man does with that theology once he has obtained it. This distinction between man’s behavior prior to the fall and after the fall will serve as a fundamental article in later formulations of the same distinction within a covenantal context. Thus, as with Bullinger, Calvin relates man’s knowledge of God to his pre- and post-fall state, and while Bullinger uses the explicit language of league in direct connection to man’s knowledge of God, Calvin makes the same connection albeit more implicitly than Bullinger does. Yet, it may be said that Calvin has a seminal doctrine of the relationship between natural theology and both the covenant of works and the covenant of grace.
 John Calvin, Institutes of the Christian Religion, (Peabody: Hendrickson Publishers, 2008), 104.
 Muller, PRRD, vol. 1, 274.
 John Calvin, Commentary Upon the Book of Genesis, (Grand Rapids: Baker Book House, 1998), 125.