Lightspeed Venture Partners, a Silicon Valley venture firm, has amassed more than $9 billion to invest in artificial intelligence. That is its biggest haul.

© Gabriela Hasbun for The New York Times

Rodney Brooks, famous for the Roomba, argues the humanoid robot craze in Silicon Valley is doomed to fail.

© Aaron Wojack for The New York Times

Beijing is pouring vast resources into fusion research, while the U.S. wants private industry to lead the way. The winner could reshape civilization.

Two columnists debate this strange moment.

“One Rulebook” is not the kind of A.I. regulation this country needs.

Generative A.I. needs a course correction for the sake of energy efficiency and for its own advancement.

I help to build A.I. systems, and even I know there are real reasons to be concerned about how A.I. affects our children.

We have arrived at a “Polycene” moment where binary systems are giving way to multiple interconnected ones.

The United States was once the undisputed leader in atomic energy. Now it is trying to catch up.