# On Exactitude in Science

Source: https://dinand.com/reading-notes/on-exactitude-in-science/
Author: Dinand Tinholt

> Borges’s one-paragraph story about a map the size of the empire it describes.

![Ornate seventeenth-century world map in two hemispheres, framed by allegorical figures and city views.](https://dinand.com/assets/reading-notes/on-exactitude-in-science.jpg)

*Willem Blaeu’s world map, Nova totius terrarum orbis tabula, around 1630. A map that admits it is smaller than the world.Image: “Nova totius terrarum orbis geographica ac hydrographica tabula”, Willem and Joan Blaeu, around 1630. Public domain, via [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Willem_Blaeu_-_Nova_totius_terrarum_orbis_geographica_ac_hydrographica_tabula.png). Resized for this page.*

Jorge Luis Borges published On Exactitude in Science in 1946. The whole story is a single paragraph, presented as a quotation from a seventeenth-century travel book that never existed.

In it the cartographers of an empire grow so ambitious that they draw a map at the scale of the empire itself, matching it point for point. Later generations find the map useless and leave it to the weather. Torn pieces survive in the western deserts, where animals and beggars shelter in them.

## Digital twins have a scale problem

The phrase digital twin invites the cartographers’ mistake. A model of a supply chain that copies every pallet and truck becomes as hard to read as the supply chain itself, and slower to change.

A useful model leaves things out on purpose, and the skill lies in choosing which. The simulation I ran on [inventory planning under uncertainty](https://dinand.com/publications/inventory-under-uncertainty/) earned its keep by staying small enough that a person could follow why a plan failed.

Old maps make the same case. A sixteenth-century sea chart draws harbours and shoals in careful detail and leaves the interior blank, because the sailor who carried it needed the coast and had no reason to go inland.

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Thorstein Veblen, 1899, and the hand-made spoon that costs more because someone made it slowly.

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### Capitalism, Socialism and Democracy

Joseph Schumpeter, 1942, on creative destruction and the new kind of organization.

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