There is a constant theme I've noticed just about anytime I present a philosophical case for the existence of God (or of any metaphysical reality) to a group of people, and especially to Atheists. Today, in one of my classes, a good example of this occurred. I had just finished going over a case for the existence of God, and as soon as I finished, one student responded, basically, "So where's the evidence for the existence of God? You haven't presented any evidence."
I've seen this sort of thing time and time again. I present a philosophical argument for some metaphysical claim, and the response is, "So where's the evidence?"
It is very frustrating. It wouldn't be frustrating if people would say, "Well, I see the argument you're making, but you've committed an error in reasoning just there." What is frustrating is that we often never get to the point of actually dealing with the argument, because I can't convince people an argument has been made at all. It is as if some of the people I talk to have some kind of blindness that prevents them from being able to see that a philosophical argument has been made and that they have to deal with it.
For most of the people I talk to, I think the blindness stems from the unquestioned assumption of empiricism. People have grown accustomed to believing that real evidence can only come from empirical observations or the natural sciences, and so they simply cannot see arguments presented in a different form. If I do a lab experiment, or read them some scientific paper written up by scientists, they are on board, or at least they will consider the evidence. But if I present philosophical arguments, they simply don't notice that any evidence has been presented at all.
This is in fact a blindness, because philosophical and logical reasoning can indeed deliver truths about the world. We need to question the all-too-often-unquestioned empircist assumption that this can't happen. All arguments need to be dealt with. We have no epistemic right to reject any argument as wrong until we have refuted its reasoning and shown why it is wrong. We cannot simply ignore arguments on the grounds that they aren't in a category we are willing to recognize.
(By the way, some presuppositionalists make the same sort of mistake. I think that in this case the problem stems from having been taught that all arguments for God or metaphysical realities from human reason are futile, so as to be able to claim that we have to simply start by presupposing something without argument. These sorts of presuppositionalists assert that the senses are unreliable, but also argue that the senses are the only means through which human reason could gain real knowledge--apart from some kind of presuppositionally-accepted revelation from God. Thus, ironically, these presuppositionalists end up agreeing with the empiricists in denying the possibility of learning anything about the world through philosophical and logical reasoning. They end up sharing the same blindness, and it shows when one tries to argue philosophically with them. Note that this is not true of all presuppositionalists, nor must it necessarily be true of presuppositionalism provided it is construed more carefully and usefully.)