Weekly Insights for Thinkers

What is the Ebbinghaus Illusion?

By Michael Alan Prestwood

Author and Natural Philosopher

12 Dec 2024
Published 1 year ago.
Updated 1 month ago.

What is the Ebbinghaus Illusion?

The Ebbinghaus Illusion plays with how our minds perceive size relative to surroundings. Imagine two identical circles. Surround one with larger shapes and the other with smaller ones. The circle surrounded by smaller shapes appears bigger, even though they’re the same size. This illusion highlights how context can warp our perception. It’s why you might seem taller standing next to shorter people, regardless of your actual height.

This concept isn’t new. Ancient skeptics like Pyrrho observed similar phenomena and used them as a cautionary tale about trusting appearances. Pyrrho’s philosophy boiled down to “do not trust until you verify,” contrasting with the empirical approach of “trust but verify.” For skeptics, illusions like this are a reminder to question not only new claims but also the beliefs and assumptions we take for granted.

The Ebbinghaus Illusion underscores how easily our perception can be tricked, urging us to interrogate what we think we know. It’s a call to think critically, constantly reevaluating our understanding to avoid being misled by appearances.


That Critical Thinking FAQ, 

was first published on TST 1 year ago.

By the way, the flashcard inspired by it is this.

Front: Which view of perception does the Ebbinghaus Illusion support?
Back: Indirect realism
All this is part of the broader TST project.
Tidbits are written to stand alone, but they are also designed to interlock—forming a research layer that supports deeper synthesis.
This project separates research, synthesis, and reflection so that each can be improved independently without breaking coherence.

The end!

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