The battles were over, but the soldiers still fought. Flashbacks, nightmares, and depression plagued them. Some slurred their speech. Others couldn’t concentrate. Haunted and fearful, the soldiers ...

Waymo is raising $15 billion to expand its robo-taxi business, according to reports.

Controlled studies capture only a fraction of the effects of artificial intelligence. Economists should work with social scientists to find innovative ways to fully grasp this fast-moving field.