At the World Question Center, 158 contributors give answers that encompass the open-ended long term and specifically short term, the disappointingly hopelessly naive (Steven Pinker: "the decline of violence"; John Horgan: "war will end") and the contradictory (Richard Dawkins: that physicists will discover the theory of everything; Frank Wilczek: that "physics will not achieve a theory of everything")
Weird and wonderful optimism! On the advantages of autism in a digital age (Simon Baron-Cohen), for the colonization of Mars (Paul Davies), and "that alternative, novel life forms might be found on our own planet" (Robert Shapiro).
Alison Gopnik's deceptively trite answer — "new children will be born" — is quite rich and wise really:
Optimism, after all, isn't essentially a matter of the rational assessment of the future — it's an attitude rather than a judgment. And it's the most characteristically human attitude, the one that's built into our DNA. The greatest human evolutionary advantage is our innate ability to imagine better alternatives to the current world — possible universes that could exist in the future — and to figure out how to make them real. It's the ability we see in its earliest form in the fantastic pretend play of even the youngest children.
I am optimistic that, someday soon, I will discover My Purpose (as well as the theory of everything).