[We insist] that sin refers to moral fall and guilt, and further, that this fall consisted in three things: a darkening of the light of reason, an impairment of the power of the will, and a corrupting of our affections. From this it follows that without spectacles, as Calvin expressed it, the book of nature can no longer be read, such that neither from nature nor from the light of our reason can we know whether, and if so, in what way, there is any means whereby we may escape the power and guilt of sin. From this flows the need for a further special revelation to be added to nature, having two purposes: both to teach us to understand again the book of Nature, and to open for us the path to reconciliation with God. So we receive a word of God in twofold form: A word of God within the creation, and a word of God with which he adds to created things (Band aan het Woord, 10).
I agree (though I disagree with the term “book of nature”).
There is, to be sure, a certain light of nature remaining in man after the fall, by virtue of which he retains some notions about God, natural things, and the difference between what is moral and immoral, and demonstrates a certain eagerness for virtue and for good outward behavior. But this light of nature is far from enabling man to come to a saving knowledge of God and conversion to him—so far, in fact, that man does not use it rightly even in matters of nature and society. Instead, in various ways he completely distorts this light, whatever its precise character, and suppresses it in unrighteousness. In doing so he renders himself without excuse before God.
Canons of Dort III.4