In an old post, Rational Compulsion, Reasoned Argument, Positing, and God's Existence, you wrote, "...my own very extreme view [is] -- that there are a lot of excellent arguments for the existence of God, some of which can be considered demonstrative (that last clause is especially rare these days) . . . " I wonder if you still hold this opinion? If so, I am particularly interested in which arguments you consider demonstrative. Best, Jarvis
It is indeed still my opinion; in fact I have become more convinced of it as time has gone on. An example of an argument that I think is essentially demonstrative can be found in John Duns Scotus's Treatise on God as First Principle; one can find an older English translation of it here. I do think it needs some updating in light of particular philosophical topics that have arisen since, namely,
(1) the external world
(2) the nature of causation
(3) the nature of explanation
But I am increasingly sure that serious consideration of each of these three topics ends up strengthening the argument, in the sense that I think the course of philosophical argument since has shown that in order to reject principles that are at least broadly like those Scotus uses, you have to make much more significant intellectual sacrifices than people usually recognize. (I am most certain of this with (1), which is the one with which I am most familiar; and a surprising number of positions on (2) and (3) that are inconsistent with Scotus's Threefold Primacy argument have very problematic consequences for (1).)
But I am not, in fact, mortally committed to such arguments actually being really and truly demonstrative; but they are good arguments that show some evidence of being demonstrative and that on close examination can be seen to withstand the major attempts to argue that they are not. Many objections to theistic arguments are put forward as if they had no serious implications beyond stopping the argument. But theistic arguments deal with fairly fundamental things. If you reject the premise of the First Way that whatever is moved is moved by another, you have, given how it is understood in argument, committed yourself to claiming that what is not actual can become actual without any causal explanation at all, and you've committed yourself to whatever reasons you use to support that conclusion. That's perfectly fine, of course, but if you are going to do this you had definitely better be willing to follow through on all the implications and be willing to address any apparent problems caused by that commitment; as Schopenhauer says somewhere, arguments are not like cabs -- you can't ride them only as far as you want and then get off. I think people have an unusually egregious tendency to treat objections as taxi cabs when arguing against theistic arguments; I'm not sure why this is so, although it could be (since you can find some of the same behavior on the other side) simply because philosophical arguments on this topic reach a massively greater audience than philosophical arguments on almost any other topic, and that this is just a byproduct of that.
The more general position here, however, is simply that (1) there are plenty of reasonable arguments that something exists that can reasonably be called divine, whether or not one wishes to consider them demonstrative (or even whether one thinks they are actually right, since arguments can be perfectly reasonable and still not be quite right); and that (2) of these reasonable arguments, at least some of them are quite excellent as arguments, whether or not one wishes to consider them demonstrative: Scotus's Threefold Primacy argument, the First Way, Boethius-style arguments for the Good, the too-often-overlooked family of infinite intelligible arguments, certain cautious arguments from religious experience, and so forth. In other words, it is not actually difficult to be a theist for reasons that stand up to examination pretty well. This is itself a fairly weak position. One can be an atheist and accept it, since it's entirely possible to believe that some arguments for X are reasonable and even quite impressive while believing nonetheless that some arguments for not-X are definitive and conclusive. It was once not very difficult to find atheists who agreed with it, although it seems to be somewhat out of fashion at present. Nonetheless, it needs to be kept distinct from the view that there is good reason to think some of these reasonable, reasonably good arguments to be in fact demonstrative, which is an entirely different position altogether: you can have very good reasons that are not even in the vicinity of being rigorously demonstrative.