For Aristotle, proofs for the existence of God come at the end of two rather long and involved sciences, physics and metaphysics. In both cases, Aristotle starts off very far away from God and then slowly steps towards him. St. Thomas takes Aristotle’s arguments more or less for granted, and takes the proofs as starting points from which he slowly steps through the divine nature, to the divine persons, to creation, the angels, the soul, the goods of the soul, etc.
We have a tendency, however, to treat the proofs for the existence of God as though they are discrete “events” that are supposed to stand on their own. We neither see them as conclusions to a science, nor as principles for another science which gives a fuller articulation of God, then treats of how such a being relates to the mysteries of Christian revelation, then treats of what our knowledge of God tells us about the physical world, how he is relevant to solving epistemological questions and moral science, etc (this is more or less the order of treatises in the Summa theologiae). Regardless of whether we think the proofs are true or not, we tend to treat them as though they were hermetically sealed off from any larger body of discourse. In practice, we are supposed to give the proof (or refute it) more or less from nothing and then forget about it as soon as we discuss revelation, cosmology, epistemology, politics and morals, etc. The upshot of this is that we never quite treat nature, knowledge, the universe, morals or politics as though God existed or not. We pretend that the question is not relevant. There is some truth to this, but at the same time it makes a great difference about what we think about nature, knowledge, morals, etc. if we come to them thinking they were the products of intelligence, benevolence, providence, etc.
Theists, for example, are all-too-prone to say something like “sure, the arguments about natural law in St. Thomas occur in a theology textbook, but one need not understand them in relation to God’s nature”. Why brag that your account of something in the Summa can work just fine apart from the five ways? Is it some kind of virtue to forget that one has reached a conclusion about something? Theist and atheist epistemologists too easily treat discussions of knowledge as it were of no decisive importance if there were some subsistent truth that determines all nature by his knowledge, or as if it were of no relevance to ones account of knowledge if we regard knowledge as something limited to human beings. For their own part, skeptics and atheists from Hume to Graham Oppy have argued that since the divine proofs do not explicitly prove every attribute that is ascribed to the divinity, that they are therefore insufficient. As if the proof were supposed to make you stop thinking! It is self-evident that if all you know about something is that it exists, you have the most minimal knowledge you can have of it. To complain that proofs for the divine existence give you a minimal account of the divinity is like complaining that the first course didn’t give you all the food you wanted. It’s not supposed to! There would be something wrong with a first course that did! The objection only makes sense- and would only be seen as an objection- if both theists and atheists regard theistic proofs as something one were supposed to give (out of little or nothing) and then promptly forget about.
This desire to isolate the argument arises from a certain lukewarmness with respect to the proofs themselves, combined with a desire to speak to everybody, avoid conflicts, and avod the scandalous an difficult claims that classical metaphysicians make. At some point, however, one simply has to take a stand and accept that what he says cannot be accepted by everyone. At some point, the acceptance or rejection of the proof has to become a principle that will divide our arguments off from others. To imagine that there is some sort of neutral, unoffensive and inclusive point of view is itself a metaphysic that is probably, in fact, rejected by everyone- theists, atheists, and agnostics alike.