The AI Reader.
Tuesday, September 1, 202641 min read
Working Knowledge · What Could Go Wrong

One line of calculus sinks the simplest way a model could hide a goal from training

The worry Evan Hubinger named in 2019 survives the collapse of its own first example, and hangs on how far real training departs from the idealized gradient descent that collapse assumes.

9 min read9 sources
Working Knowledge · The Evidence

Segment Anything returns a mask and never a name

Kirillov and his Meta coauthors let the 2023 model draw 99.1% of its own billion-mask training set, then measured it losing to a task-specific model on the standard segmentation score.

8 min read6 sources
Working Knowledge · The Instruments

Two AIs reported the same 35/42 gold at the 2025 IMO, and the IMO graded only one

An IMO medal is a proof scored by hand against a rubric, which makes the grader part of the number and turns one gold medal into two different measurements.

8 min read12 sources
Working Knowledge · The Mechanics

Quantization rounds a model's weights to a coarser grid, and a few oversized values decide what that costs

A careful 4-bit scheme costs a 7-billion-parameter model under 1% of its perplexity, but round the same weights naively, or below four bits, and its answers can collapse.

8 min read8 sources
Working Knowledge · When AI Breaks

Meta's Galactica invented citations for real researchers, and its public demo lasted about two days

The demo warned on every output that the text might be invented, and Meta's own paper had already measured the model fabricating most citations to rarely-cited work.

8 min read9 sources