Ray Kurzweil and his son, Ethan, are both Silicon Valley futurists—though they have different ways of tackling what they perceive is coming next.

Ray Kurzweil, 65 years old, joined Google Inc. in December after spending nearly five decades pioneering everything from machines that can read text aloud to the blind to a music synthesizer that sounds like a real piano.

Among his theories, which aren't universally accepted in the technology world, is the "Law of Accelerating Returns." This states that technological progress increases exponentially, eventually allowing people to enhance their intelligence and live forever. He also envisions a future in which artificial intelligence surpasses human intelligence and spreads out across the universe, which he calls "the singularity."

Mr. Kurzweil is now forming an engineering team at Google's Mountain View headquarters, where he is attempting to use software to replicate the human brain's "pattern recognition" abilities—a topic discussed in his new book, "How to Create a Mind." The hope is to build a system with human-level understanding of the world and, by giving it access to Google's mighty index of digital information, create the ultimate virtual assistant—and more.

Ethan Kurzweil, 33, is a futurist through his attempts to invest in the next big thing. Earlier this year, he became a partner at Bessemer Venture Partners, a Menlo Park venture-capital firm. His Bessemer investments include online-dating site Zoosk Inc. and CrowdFlower Inc., which helps companies quickly find workers to perform tasks online.