Brian Christian has spent 20 years thinking about how artificial intelligence will change our minds and our world. His 2020 book "The Alignment Problem" has been praised as one of the best on AI, and like many scientists, he sometimes feels euphoric about the technology's advances. After all, when everyone has a fleet of autonomous agents on standby to speed up research, it's hard not to feel as if a life-changing discovery is just a few prompts away.