Thanks for another thoughtful and meaty reply, Jordan.
Your approach makes sense, given your biographical comments. It sounds as if you’ve never really left Christianity, and therefore would be more interested in arguments that show an already existing belief in God to be consonant with reason and science, than in arguments that try to demonstrate the existence of God from scratch.
On the other hand, if we think in terms of evangelism in a world in which, for many, the very existence of any God is regarded as impossible or at best dubious (the religious “Nones” in the USA are now up to about 20% and climbing), it becomes necessary to ask how to bring an unbeliever, who in many cases may never have been inside the door of a church (except for weddings and funerals of friends) to concede that God does or may exist. It makes no sense to start by trying to convince someone that Jesus is God, or even just the Son of God, if the person you are trying to convince doesn’t think any God exists. If God is a fiction, then any Son of God or any Trinity is equally a fiction, and any book allegedly inspired by that God, i.e., the Bible, is equally fictitious.
From this point of view, natural theology – the attempt to establish the existence of God, and some of his broader attributes, on the basis of reasoning from nature, without any appeal to the authority of any revelation – can for some people be a useful prelude to Christian faith, a sort of vestibule which later can lead to the other rooms in the house. Some of the Church Fathers regarded Greek philosophy as fulfilling this role in the evangelization of many Gentiles, since Greek philosophers offered natural theology arguments for a Deity (along with a loftier and almost monotheistic ethics in comparison with typical pagan ethics).
I wouldn’t say I was ever really at heart an atheist; I was, however, for a long time agnostic (despite a lukewarm church upbringing, there was a strong streak of skepticism in my family which I imbibed), and my own trajectory was more like that of Lewis. It was in the university, not in the church, and from professors trained in philosophy, not from any clergymen I had ever listened to, where I learned that the idea of God, far from being outmoded and irrational, was intellectually respectable. After reading thousands of pages of the classic expositions of philosophers and theologians, and numerous pieces by the some of the more philosophical scientists, I ended up persuaded that reality could not be explained (satisfactorily to me, anyway) without reference to God or at least some supreme Mind behind the world. So when I later encountered some evangelical students of the more intelligent type (the ones I met in graduate school in Religious Studies, not the ones I had met in first-year undergrad waving their Four Spiritual Laws pamphlets), I was already on the “God exists” side, and unsure only about Christianity. So my Christian friends and acquaintances had something to build on.
To be sure, it was traditional natural theology, not ID, that had served as the bridge for me, but when ID came along much later, I immediately recognized it (the first author I read was Behe, who accepted common descent) as a modern presentation of natural theology (with molecular machines replacing, as the main focus, the machinery of skeletons etc. in the older account of Paley). And Denton’s Nature’s Destiny says explicitly that his conclusions vindicate natural theology. I doubt that many modern agnostic undergrads studying science would have the patience to read natural theology as presented by traditional philosophers, but some undergrad science students do actually read general science books outside of class, and there is some hope of persuading a science major to read a book like Nature’s Destiny, which describes the history of the universe much in the same molecules-to-man way that Carl Sagan did (and therefore would make the science major comfortable) but interprets that history in teleological terms. Someone like Denton (and there are a number of other “fine-tuners” that could be named in his place) can therefore serve as the sort of bridge between agnosticism and Christian faith that Plato, Aristotle, the Stoics, etc. were in times past.
I’m not saying the majority of conversions to Christianity proceed in this cautious, stepwise way through either traditional natural theology or ID, but the case of Lewis and others indicates that this possibility should not be rejected.
Of course, there can be other reasons for believing in God, beyond ID or natural theology reasons. I’m interested in hearing those other reasons from the remaining self-declared Christian scientists here.
On the other subject you deal with, your remarks in the main make sense to me, and since it was a side-remark of mine you were responding to, I don’t think we need to pursue it.