Greek Mythology Notes
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Theseus (Ship)

concept
Θησέως πλοῖον
The philosophical paradox of identity

The Ship of Theseus is a thought experiment about identity: if you replace every plank of a ship one by one, is it still the same ship?

The Myth

The Athenians preserved the ship Theseus sailed to Crete in their harbour for centuries as a sacred relic. As planks rotted, they were replaced with new timber. Plutarch asked: at what point does it cease to be Theseus's ship? If all the original planks are replaced, is it the same ship? And if you reassembled the old planks into a ship, which one is the "real" ship of Theseus? This became one of Western philosophy's foundational problems of identity, still debated in philosophy, law, and computer science.

Symbols

shipreplaced planksidentityharbour

Fun Fact

The Ship of Theseus paradox has been used to debate everything from personal identity to patent law to the question of whether a restored building is "original."

Words We Inherited

English words and phrases that trace back to this myth:

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