I was watching the clip in WandaVision when then two visions meet and the question of the Ship Of Theseus came up.
The Ship of Theseus originates from a story about the legendary hero Theseus, whose ship was preserved by replacing its wooden parts one by one as they decayed. Over time, none of the original materials remained, yet it was still called the same ship. This raises the question: if nothing from the original remains, is it still the same ship?
Later, the philosopher Thomas Hobbes expanded the thought experiment. He imagined that all the original, removed parts were collected and reassembled into a second ship. Now there are two ships: one that maintained continuity through gradual replacement, and one that was reconstructed from the original material. Which one, if either, is the true Ship of Theseus?
Hobbes considers that both possess parts of the original ship’s identity. One ship retains the form—the continuity, function, and historical role of the original—while the other retains the matter—the actual physical components.
Cognitive Psychologists have also used this thought experiment to explore how we maintain our concept of identity, as we are exposed to physical and psychological changes.