Who exactly is "Simple Truth" aimed at? As far as I can tell, the message is that worrying about the cashing out the meaning of truth is not worth the effort in ordinary circumstances. That's true, but it is a fully generalizable counter-argument to studying anything - worrying about the meaning of "quantum configuration" has no practical payoff, even though building things like computers relies on studying those sorts of things. Likewise, the meaning of truth is really hard if you actually examine it.
Put differently, religious people don't disagree with us about truth means, they disagree about what is actually true. And they are wrong, for the reasons detailed in "Making Beliefs Pay Rent." In short, no real person is analogous to Mark, so no real person's philosophical positions are contradicted by the story.
To repeat, the story doesn't solve any real questions about truth, it simply says they are practically [Edit] unimportant (which is true, but makes the story itself pretty unhelpful),
For me the message of "Simple Truth" was that the intelligence should not be used to defeat itself. To be right, even if you can't define it to philosopher's satisfaction, is better than to be wrong, even if you can find some smart words to support that. The truth business is not about words (that's signalling business), but when you are right, nature rewards you, and when you are wrong, nature punishes you. (Although among humans, speaking truth can cause you a lot of trouble.) At the same time it explains the origins of our ability to understan...
If it's worth saying, but not worth its own post, even in Discussion, it goes here.