David doesn't argue--he sings!
Taking it that Jewish tradition is correct David wrote this in Psalm 19:1, "The heavens declare the glory of God; the skies proclaim the work of his hands." He goes on to say that their message goes out ceaselessly to the ends of the earth.
Because this is true—and it is, of course—we believers are tempted to claim that you only have to look at the creation to know that "there is a God." But that certainly isn't what David said.
We mustn't make less of what David said. He didn't say that the creation declares the glory of some god or other. Gentiles might say such a thing—and they often did. Ancient nations (and moderns ones too) look at creation and say it proclaims the glory of———or someone else. But that's not what David said. He makes the claim that the one true God that manifested himself to Israel is the creator and that when the creation speaks it speaks of Him.
If you had asked David how he knew that—for the moment shelving any discussion about "inspiration"—he would have told you that he had been taught it since childhood. In this text he isn't making an argument based on reason, he's proclaiming his faith, he's proclaiming truth that God had revealed about himself. When he says the heavens proclaim God's glory he knows it because he knows the God who made it! There is no philosophical argument here. It is theology and faith pure and simple. There's no "design proves a designer" about this text. For David "God" is not the conclusion of a syllogism or a logical inference from empirical realities.
Certainly he knows that the God who made the creation is all-powerful but he knows that because God told him! If you took a walk with David some star-filled evening or some blazing sunlit morning he'd sing you a song about the glory of God in these things. And if he did he wouldn't be "inferring" anything! He'd be bearing witness to the faith of his people and of his own heart; a faith that was revealed to him. Once you know it is God (the one true and living God, who revealed himself to the human family) you look at the splendour of the creation and say it is God's handiwork. But when you say it is God's handiwork you wouldn't be saying anything as shallow as: "This is the work of some supernatural being(s)," as Anthony Flew now says.
If you made a rational argument to David and said that you were doing what he was doing in Psalm 19 he'd laugh out loud. We mustn't reduce an inspired utterance to a rational argument. We mustn't say, "See? David is saying you can reason from the creation to God!" He says no such thing! We mustn't claim that a rational argument could produce a Psalm 19! It just isn't so!