Great teachers and challenging ideas

I first came across Theseus's paradox, (also known as Theseus's Ship) sometime in my teens, perhaps my early teens. Plutarch has a good version of the paradox.

The ship wherein Theseus and the youth of Athens returned from Crete had thirty oars, and was preserved by the Athenians down even to the time of Demetrius Phalereus, for they took away the old planks as they decayed, putting in new and stronger timber in their places, in so much that this ship became a standing example among the philosophers, for the logical question of things that grow; one side holding that the ship remained the same, and the other contending that it was not the same.

Theseus's paradox has exercised philosophy students ever since the ancient Greeks.

It's resolution relies entirely upon reaching agreement on definitions but is a great catalyst for thought, debate and inquiry.

Aritstotle resolved the paradox by introducing the valuable concept of telos, the nature or purpose of a thing. The essence.

I was lucky to have teachers who knew about such things as Theseus's paradox and were happy to slip it into classroom discussion time.