In Calvin’s Institutes (book I, chapter 1, section 1, McNeil ed.) he opens his massive tome with epistemology
Why? How does this follow? For Calvin, from the “feeling of our own ignorance, vanity, poverty, infirmity, and-what is more-depravity and corruption, we recognize” that all goodness, righteousness and light reside in Him alone. That is, recognition of our sins requires recognition of God. For the unbeliever this is not saving knowledge, but for the believer it illumines our minds, blinding our eyes by the majesty of His Holiness. The Spirit through the Law shows us our depravity and rebellion that only make sense in reference to God-Romans 1 argues that all men know God from his handiwork.
But this is not all: without knowledge of God there is no knowledge of self. Again why? How? Calvin asserts that “we always seem to ourselves righteous and upright and wise and holy-this pride is innate in all of us-unless…we stand convinced of our unrighteousness and foulness…” So, he reinforces his first point that an honest examination of ourselves (by the Spirit) will show that we live in rebellion against the King of the universe. Calvin is not saying that we find God in ourselves because we possess a self-sufficient standard of judgment, rather: “we are not thus convinced if we look merely to ourselves and not also to the Lord, who is the sole standard by which this judgment must be measured” (37).
In other words, by seeing our own sin and misery we will be displeased with ourselves and seek God. And we would never even see our true miserable selves without God, the sole standard by which judgment is measured. If you want to know the glories of God’s perfection, pray the Spirit, through the Word, to illumine your eyes and know thy self.