MENTAL MODEL · M2379

Epicycles

CultureHigh supportPhilosophy

Included

Version 1.0.0 · Updated 2026-07-30

CORE DEFINITION

During the geocentric era, to explain the discrepancy between planetary trajectories and observations, astronomers did not seek the cause at the core of the model (the Earth's center), but instead added numerous complex "small circles" (epicycles) on the periphery to forcibly fit the data. As a result, the model became extremely complex and ugly, until Copernicus proposed heliocentrism, and everything became simple instantly. -

SCAFFOLDING EFFECT

psychology

Reduce cognitive load

A precursor to model collapse. - When you find that a theory, a codebase, or a lie requires countless patches to maintain explanatory power, it is an "epicycle." Do not continue patching; this indicates that the core assumption is wrong. Tear it down and start over, seeking that "heliocentric model."

anchor

Anchor fast decisions

In Ptolemaic astronomy, a geometric construction introduced to explain the apparent motion of planets, including stations and retrogradations: the planet moves along a small circle (the epicycle), whose center moves along a larger circle (the deferent) around the Earth.

MINIMUM ACTION

In progress 0/3

Practice this model in one real situation:

Use the deferent to describe the planet's mean orbit
superimpose periodic motion on the epicycle to fit observed retrogradations
adjust radii and speeds to make the model match observations.

Check to track your progress (stored locally)

Learning progress0%

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Source support: Explicit

link
en.wikipedia.orghttps://en.wikipedia.org/wiki/Deferent_and_epicycleZH · Explicit
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