The world is filled with problems. Many of them can be solved with hardwork. If that hard work is not getting done, then the meta-problem, how toget that hard work to happen, cannot be solved with hard work. Eventually the solutions to problems abstract into intellectual problems.
And if all problems are intellectual, then there is no problem that wouldnot be better treated with more intelligence. Any unsolved problem will likely only be solved through the use of intelligence.
Artificial Intelligence is the study of intelligence in natural and artificial systems. I believe that someday artificial reasoners will be smarter than people in every way. Therefore, to me the best way to solve all the world's problems is by improving the tools we use to solve them--intelligence. It's sort of the root of all solutions.
Every time I think of a problem that might be more important, like the fact that people die, the fact that the rain forests are being destroyed,etc., I remind myself that all of these problems could benefit from greater intelligence. AI has to be applied to something: The AI is applied to what? So right now, for example, I'm working on AI systems that help us understand molecular biology. That is great, to me, because I'm working, really, on two problems at once: the protein folding problem and the greater problem of how to think and reason and solve problems in the abstract.
This is why I believe that AI is the most important thing to be working on: it has the potential to help us solve all problems.