If you could solve one problem in the world, what would it be? One random answer will win a $50 Amazon gift card. [Details here]
I had an epistemology professor my first semester at Cleveland State who said that 90% of the world's problems came down to a bad epistemology. I don't know that I'd go that far (for one, a philosopher should know better than to quantify when you can't possibly survey all the problems in the world!), but the thought made a powerful impact on me. And I'll agree with this much: if we had a decently-worked out epistemology, problems would be a lot simpler.
"Epistemology" is a fancy word for the science of knowing. It's not so much the facts we know but the way we have all agreed to use them. What counts as evidence, in what context; what our terms mean; what it means for something to be true; that kind of thing. It's basically how you avoid talking past each other. I am tired of the pain and lost friendships and lost potential over one group using a word one way and another group using it another way, and them getting upset while really they're much closer to agreeing than either seems to think.
So if I could solve one problem, it would be to give them the ability to actually work out their other problems - see the true disagreements, and see where the labels are getting in the way and creating false-wars.