4 JAN 2026

Day 4

I think, therefore I am.

René Descartes · Discourse on the Method

A crescent-shaped gold cape, heavily decorated with concentric bands of raised ribs and small circular bosses, fitted to cover the shoulders and upper chest with small armholes.

I · THE OBJECT · BRITISH MUSEUM

The Mold Cape

Bronze Age Britain · c. 1900–1600 BC · Gold

Hammered from a single sheet of gold and fitted so tightly it pinned the arms to the body, this Bronze Age cape was never meant for walking around in.

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II · THE IDEA · ARTIFICIAL INTELLIGENCE

Loss: How a Model Knows It Is Wrong

Foundations · Cross-entropy, negative log-likelihood · Single scalar per prediction

Training adjusts billions of weights, but every adjustment is steered by one scalar: a measure of surprise when the model's probability distribution meets the actual next token.

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Painted cave interior showing a vaulted ceiling covered in geometric patterns and celestial figures, with large Buddha statues seated against the walls and narrative scenes in horizontal registers above them.

III · THE WORK · ART HISTORY

The Cave Paintings of Dunhuang

Dunhuang, Gansu province, China · 366 CE–14th century · Cave temple complex

A thousand years of continuous painting ended when someone bricked up a chamber containing fifty thousand manuscripts. In 1900 a Taoist monk knocked through the wall.

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