Hi Jeff. Thanks for the comment. It might be fair to say that my theological assertion that God intentionally created humans in his image is “a useless explanatory appendage” from the perspective of scientific explanation. It is not doing any scientific work. But then Ockham could be brought in only if we say that scientific explanation is the only useful kind of explanation. Is it useful in other ways to affirm that humans are intended creations and not accidents? I think so, and refuse to recognize science as the ultimate authority on the question of human nature.
Now, that is not to say that science is irrelevant for the question of human nature. And I also think there are some fruitful scientific ideas about evolution that resonate with the Christian theological story about the development of humans, e.g., the clear directionality in evolution, cooperation and altruism, convergence. These ought to be in dialogue with theological ideas. But I wouldn’t say these scientific explanations render the theological one useless.
What I am resisting is the urge to translate theological language into scientific language. When that kind of reduction is made, then if there is a scientific explanation, the theological explanation becomes redundant and useless.
As for your guy on the plane: I can see that the Dawkinses and Coynes of the world think that’s what’s going on with my theological explanation. And I don’t pretend that I can show them otherwise from the science itself (which I take to be an ID approach). But maybe I can show that their view of things leaves out some aspects of reality that are important… or at least have been important to a community with a long tradition. If there is a community of people who think their explanation of how planes fly gives a better and richer understanding of reality… I’m willing to listen.
Another thought on the plane example: lift and thrust may offer a complete explanation of one aspect of what allows the plane to fly. But wouldn’t you want to say there are aspects to this question that need other kinds of explanations? There are paying customers who allow the plane to fly, and their intentions for travel. And there are laws and regulations that allow the plane to fly. Are these useless explanatory appendages?