Among all arguments that get called “design” arguments, I can see a clear value in a.) those that are based on the intrinsic final causality in nature and b.) those that are based on marveling at nature. I’m skeptical of all others. The second sort of arguments are best when most immediate – having more than one step in the argument usually kills them, and trying to capture the argument in words usually falls flat.
Describing marvels can easily come out as though we are describing our own ignorance. But though there is an element of ignorance in marveling no one finds mere ignorance marvelous or desirable. There is something incommunicable in the act of marveling – like an engaged person who suddenly realizes what is coming and says “I’m going to get married”. It’s not that he didn’t know this fact before or that he recognized some new fact that related to this, but that he has insight into a fact that he and everyone else knows. When he tries to explain what he saw, all he can do is repeat the same fact that everyone knows, perhaps while he stresses the word “really”- “”Whoa…I’m really going to get married…”.
There is also an opposite experience to this marveling at nature. Call it R. It’s hard to look at the ephippiger wasp’s method of feeding its young (as Darwin did) or the mating habits of the praying mantis or black widow without having at least a mild case of R. The sheer size of the universe with all of its vast empty parts also might incline us to the same thing. Some argue that the whole story of evolution is R, but a more time tested example would be the painful death of a young child.
Philosophy might have a role to play in arbitrating between marveling and R, but I’m not sure how much of one. The sort of argumentation proper to rhetoric and art is more appropriate here. Perhaps it’s simply a lesson that nature prefers to teach herself. But this would be to put it in a way to be marveled at.