More from Berkouwer on the relationship between general and special revelation:

We have in mind only that, in the most profound sense, no true knowledge of the revelation of God in the works of his hands is obtainable without faith in Christ. Calvin’s reference to the glasses (of faith) as the only means whereby we can know God in this book of “nature,” is of decisive significance for all reflection on general revelation. This is not a question of our knowledge of nature as such, but rather of our knowledge of God’s self-revelation. Stated otherwise, in Dogmatics general revelation is not to be regarded (in isolation) as an independent object of study. Reflection on dogmas is in principle different from activity in the natural sciences. . . .  

The relationship between general and special revelation is not a competitive one; but in special revelation our attention is focused on the universality of God’s actions in relation to (the plan of) salvation and the Kingdom of God. It is precisely this salvation of the Lord which calls forth a song of praise about the works of God’s hands, indeed, this hymn of praise is a part of that salvation. When we speak of the general revelation of God, then we are concerned with this universality of God’s actions in created reality” (G. C. Berkouwer, General Revelation, 285-286).