It's obvious and observable that people suffer, but it's neither obvious nor observable that the suffering in the world is 'pointless.' Alvin Plantinga has pointed out a flaw in this reasoning with a fun thought experiment: suppose I ask you too look in a tent and tell me if there's a saint bernard inside. In this case, I have every reason to trust what you say, since a saint bernard is just the sort of thing I would expect you to be able to observe inside a tent. But suppose I ask you to look inside and tell me if there are any 'no-see-ums' inside the tent (apparently, a no-see-um is gnat with a big bite that is small enough to pass through the netting of a tent, and so is too small to see). Now, I have no reason to trust your answer in this case, since you can't see no-see-ums. Here's the problem: you're assuming that if there's a reason for our suffering, it's more like a saint bernard than it is like a no-see-um. This, however, is simply assumed; it's not argued for. It is certainly at least possible that we suffer for a reason, but that that reason is not something we can easily detect.
Thought this deserved a fuller response here.
First off, yes it is “at least possible that we suffer for a reason, but that that reason is not something we can easily detect”. “Possible” being the key word. Possible, but not remotely probable, I'd suggest.
After all, it’s also possible this world is the creation of an all-powerful all-evil God, and that there is a reason for the good stuff we find in it – it's just a reason we cannot easily detect. But how probable is that, given the amount of good we find in the world? Highly improbable, of course!
I am running not the logical problem of evil, remember, but the evidential problem (see here). I suspect Plantinga is here responding to the logical problem (is he?).
I certainly don’t think this is a good response to the evidential problem.
Here’s another thought experiment. Suppose we see an adult slowly torturing children to death. We would immediately conclude the adult was not at all good. And for very good reason.
But now suppose we find out that the adult is vastly more intelligent and knowledgeable than us - an alien super-being. Surely, that would not lead us to revise our initial opinion very much.
Yes, perhaps there is some reason why torturing these kids to death is ultimately all for the best, and this being can see that, while we cannot. But that remains highly improbable, surely. The most reasonable conclusion to draw remains that the torturer is not particularly benevolent.
Pointing out the mere possibility that there is some good reason for the torture that we can’t see (not being as intelligent or knowledgeable as the torturer) does very little to weaken the evidence that whatever the torturer is, he ain't entirely loving and benevolent.
Ditto, say, our creator unleashing literally unimaginable quantities of suffering on sentient creatures over hundreds of millions of years.
Perhaps there’s some good reason for it. But the fact remains, the sheer quantity of suffering is still very good evidence that the creator, if he exists, is not supremely benevolent. In which case he is not the Christan god.
Of course, we can and should acknowledge that if there is a limitlessly wise and all-knowing God (whether good or evil), then very probably some of what he does will be mysterious to us.
But that doesn't mean that nothing can count as evidence against his goodness or badness, does it? It doesn't mean that, however heavenly or hellish the world happened to be, it would still not provide us with good evidence for/against the creator's goodness/badness.
If vast quantities of good are excellent evidence he is not all evil - and they surely are - then vast quantities of evil are excellent evidence that he's not all good.
[incidentally, if there is a good reason for the suffering, why could not God explain it? If I inflict pain on my child for good reason - at the dentist, say - I explain why I do so. Failure to explain would be particularly cruel. If there is a good reason for e.g. burying thousands of children alive in Pakistan, why doesn't God explain?]