I am proud to be among the list of 25 initial signatories — all Fields Medallists — to the declaration below, which grew out of discussions between ourselves over the last week. We have…

In the wake of turmoil at OpenAI and Anthropic, it’s become common to describe A.I. as a kind of person, hatching plans and pursuing desires. The truth is a little trickier.

What To Fear from AI Agents and How to Reclaim Our Human Agency

This paper argues that fully autonomous AI agents should not be developed. In support of this position, we build from prior scientific literature and current product marketing to delineate different A...

My keynote at ICML 2026

The idea that artificial intelligence can “reason” is more intuitive than ever. But intuitions can be wrong, and the science is far from settled.

LLMs see the world as a single stream of text, partitioned into roles like <user> or <tool>. We trace prompt injection to role confusion: models perceive the source of text from how it sounds, not its...