Knowledge is invariably a matter of degree: you cannot put your finger upon even the simplest datum and say this we know.
The belief in God is not therefore based on the perception of design in nature.
Belief in design in nature is based upon the belief in God. Things are as they are whether there is a God or not. Logically, to believe in design one must start with God. He, or it, is not a conclusion but a datum. You may begin by assuming a creator, and then say he did this or that; but you cannot logically say that because certain things exist, therefore there is a God who made them. God is an assumption, not a conclusion. And it is an assumption that explains nothing.
The dualism itself becomes a sort of presupposition or datum;
its terms condition the further problem.