Silicon Valley futuristic By Brandon Bailey bbailey@mercurynews.com Silicon Valley billionaire Peter Thiel worries that people aren't thinking big enough about the future. So he's convening an unusual philanthropic summit tonight at which he will introduce other wealthy tech figures to nonprofit groups exploring such futuristic -- some might say "far out" -- ideas as artificial intelligence, the use of "rejuvenation biotechnologies" to extend human life, and the creation of free-floating communities on the high seas. "We're living in a world where people are incredibly biased toward the incremental," said Thiel, explaining that he wants to challenge his peers to pursue more "radical breakthroughs" in their philanthropy by supporting nonprofit exploration of technological innovations that carry at least the promise of major advances for the human condition. "Obviously there are a lot of questions about t...