Alva Noë has written a short piece on love for NPR, which ends with the question "Can you love the whole world?". What is interesting is not the question itself, but what he compares the question to:
Can you love the whole world? I suppose this is like the question, Is there a God?
My answer to both questions is "No" (if "the whole world" refers to every human being in the world and if "God" refers to a personal God who listens to and answers prayers). There are, however, many people who would answer "No" to the first question but "Yes" to the second. But even for these people, the two questions are alike in the respect that both require us to look beyond ourselves and our immediate concerns. Both are in this sense demanding questions and should not be answered lightly.
