21 AUG 2026

Day 233

The fundamental problem of communication is that of reproducing at one point either exactly or approximately a message selected at another point.

Claude Shannon · A Mathematical Theory of Communication

A group of earthenware figures of differing heights, arranged together against a plain pale background, their fired-clay surfaces mottled and dulled with age.

I · THE OBJECT · BRITISH MUSEUM

Tang dynasty tomb figures of Liu Tingxun

Tang dynasty China · tomb of a man who died in 728 AD · earthenware

Thirteen earthenware figures, buried for a general who died in 728, dug out at Luoyang and now standing in London — and almost everything else about them is inference.

Enter lesson 5 MIN

II · THE IDEA · ARTIFICIAL INTELLIGENCE

Model-Based RL and the Limits of a Learned Simulator

model-based reinforcement learning · MBPO, 2019; Bayesian REX, 2020 · ensemble disagreement as an uncertainty signal

A learned simulator is useful for a few steps and dangerous after that. One family of methods answers the question of how far to trust it by watching several models disagree.

Enter lesson 7 MIN

A hilltop city of pale stone walls, packed roofs and tall towers, rising above green folded slopes and a river crossed by a bridge, beneath a large dark grey-blue sky torn by lighter streaks.

III · THE WORK · ART HISTORY

View of Toledo

El Greco · 1596 · Oil on canvas

Only two landscapes by El Greco survive. This one puts a whole city under a sky that has gone almost black, and lights the buildings from nowhere in particular.

Enter lesson 6 MIN