How large language models can reconstruct forbidden knowledge

In the late 1970s, a Princeton undergraduate named John Aristotle Phillips made headlines by designing an atomic bomb using only publicly available sources for his junior year research project. His goal wasn’t to build a weapon but to prove a point: that the distinction between “classified” and “unclassified” nuclear knowledge was dangerously porous.

The physicist Freeman Dyson agreed to be his adviser while explicitly stipulating that he would not provide classified information. Phillips armed himself with textbooks, declassified reports, and inquiries to companies selling dual-use equipment and materials such as explosives. Within months he had produced a design for a crude atomic bomb, demonstrating that knowledge wasn’t the real barrier to nuclear weapons. Dyson gave him an “A” and th