In a comment on Facebook (1/14/11), I made this observation: “Most of us have misunderstood Romans 1:18-21. The unbeliever not only knows THAT God exists but WHO God is; his covenant head. Suppression of the truth therefore takes on a far deeper meaning."
The passage in view teaches that fallen men know THAT God is. But their knowledge is also knowledge of his “invisible attributes” and “divine nature” (v. 20). And it should be added that they also have a personal knowledge of God—i.e., they know HIM, not just information about him (v. 21). And of course this includes knowledge of God’s ethical standards (see the rest of chapter, esp. v. 32).
Like Van Til, I think it is silly to say that someone knows THAT God is but is completely ignorant about WHO he is. How can you know the existence of something without knowing anything at all about its nature? On that premise, you can’t even specify what it is that you know the existence of. If I say I believe in the existence of mountains in Alaska, my belief certainly includes a claim to know what a mountain is.
In the language of Romans 1, the non-Christian denies the existence of mountains in Alaska. Yet his denial of mountains in Alaska still assumes that he knows what a mountain is (via negative). Likewise, the unbeliever’s denial of God assumes who he is denying.
So if someone says he believes in God, he must have some idea of what he means by God, what sort of God he believes in. For someone to say he disbelieves in God, he must have some idea of what he means by God, what sort of God he disbelieves in.
So the question amounts to “how much do fallen people know?” Or “what specifically do they know about God?”
“Eternal power,” “invisible attributes,” and “divine nature” (v. 20) are each very comprehensive phrases and Paul explicitly says the unbelievers’ knowledge includes these things, that is, God’s omnipotence and eternity. God’s love/justice is also implicit in what Paul says about the moral standards of God. And certainly the whole chapter pictures God as knowledgeable about what is happening in the world, giving up people to unbridled lusts, and so on.
But referencing the Facebook statement above, can we go as far as to say that fallen men know “deep down inside” that they are in covenant with God and therefore covenant-breakers? Paul never uses the term “covenant” in Rom. 1, although Isaiah 24:5 may allude to that. In any case, it’s important here to formulate some understanding of what “covenant” means. Covenant is a Lord/servant relationship, and clearly the sinners of Rom. 1 understand that. Further, covenants in Scripture all have the same essential elements: God’s name, historical prologue (grace), stipulations, sanctions, and administration.
In Rom. 1, fallen men know who God is (the name). They have the responsibility (stipulations) to obey and worship God—always a covenantal responsibility in Scripture. Those responsibilities are accompanied by blessings for obedience, curses for disobedience (covenant sanctions). Clearly what happens in Rom. 1 is that God administers curses for disobedience.
Now there is no “historical prologue” in Rom. 1, but interestingly Paul brings in something like this in Acts 14:17 and 17:24-30: the historical prologue (previous grace) is the fact that God has given to people the benefit of living in his world within fixed “bounds of habitation” and “fruitful seasons.” They ought to be grateful for such unmerited favor and should worship the true God alone.