It's rational for David to believe it, just like it's rational for you to not believe it. It wouldn't be rational to kill for one's belief, but to just believe in a higher power and to follow a religion for the sake of it, isn't necessarily inherently irrational, imo.
My dear beloved Deidre,
Interesting thoughts! I would like to ask some questions for clarification, if that's alright.
But first -- so you know where my questions are coming from -- I should probably first state that I myself use the word "rational" to mean "based on empirical fact and/or logical reasoning". So far as I can see, empirical fact and logical reasoning are "open to public verification" in the sense that, almost anyone can under the right circumstances verify those things.
For instance, suppose you just happen to have a giant, 20 foot tall, ghastly pink statue of me in your backyard that you bought from one of my ex-wives who herself had it commissioned in order to remind her of how ugly I am. The fact that you can see the statue means you can empirically verify that it exists. But so can I. I too can empirically verify that the statue exists if I too can see it. That's what I mean by "open to public verification". If something is an empirical fact, then just about anyone can empirically verify it.
And the same goes true for logical reasoning. Just about anyone can verify that, say, 2 + 3 = 5 is logically sound.
So that's the where I'm coming from when I use words like "rational" and "irrational". Now, when you say, "It's rational for David to believe it, just like it's rational for you to not believe it.", I must admit your use of the words "rational" and "irrational" don't seem to jive with mine. Because to me, anything that is rational is open to public verification, and so if it's rational for David to believe something, then it is also rational for me to believe it. If there's a ghastly pink statue of me in your backyard, and it is rational for David to believe there is, then it is rational for me to believe there is -- assuming both David and I have equal access to the very same means of verification.
Now please don't misunderstand me. I am NOT about to argue that you should use the words "rational" and "irrational" to mean the same things I mean by them. No! No! No! The very idea that I might suggest that shocks me! It would mean I was one of those loathsome semantic imperialists who blunder around trying to impose their favorite definitions of words on everyone else. And I just ain't no semantic imperialist. In my view, you have just as much right as do to use words however you see fit. I only beg that you make the meaning of your terms clear to me.
Having said all that, could you please tell me how you are defining "rational" such that David is rational to believe something that I am rational to not believe.
Moreover, I think I agree with you when you say, "to just believe in a higher power and to follow a religion for the sake of it, isn't necessarily inherently irrational", but my reasons for agreeing with you might not be the same reasons you have for saying what you said. I agree with you because I interpret "following a religion for the sake of it" to be different from "following a religion because you rationally believe its truth-claims are indeed true". For instance, I might "follow a religion for the sake of it" without being rationally convinced its truth-claims are true, but I am instead following it in the manner of "trying it on for size". So I ask could you explain what you mean by "to follow a religion for the sake of it isn't necessarily inherently irrational?
Last, please allow me to beg your forgiveness for making you wade through all my insufferable thoughts on this matter.
Yours in Faith in the Sacred Rejuvenating Beauty of Erotic Dancing Girls,
Phil