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  • Throughout the history of mankind,

  • three little words have sent poets to the blank page,

  • philosophers to the Agora,

  • and seekers to the oracles:

  • "Who am I?"

  • From the ancient Greek aphorism inscribed on the Temple of Apollo,

  • "Know thyself,"

  • to The Who's rock anthem, "Who Are You?"

  • Philosophers, psychologists, academics, scientists, artists, theologians and politicians

  • have all tackled the subject of identity.

  • Their hypotheses are widely varied and lack significant consensus.

  • These are smart, creative people,

  • so what's so hard about coming up with the right answer?

  • One challenge certainly lies with the complex concept of the persistence of identity.

  • Which you is who?

  • The person you are today?

  • Five years ago?

  • Who you'll be in 50 years?

  • And when is "am"?

  • This week?

  • Today?

  • This hour?

  • This second?

  • And which aspect of you is "I"?

  • Are you your physical body?

  • Your thoughts and feelings?

  • Your actions?

  • These murky waters of abstract logic are tricky to navigate,

  • and so it's probably fitting that to demonstrate the complexity,

  • the Greek historian Plutarch used the story of a ship.

  • How are you "I"?

  • As the tale goes, Theseus, the mythical founder King of Athens,

  • single-handedly slayed the evil Minotaur at Crete,

  • then returned home on a ship.

  • To honor this heroic feat, for 1000 years Athenians painstakingly maintained his ship in the harbor, and annually reenacted his voyage.

  • Whenever a part of the ship was worn or damaged,

  • it was replaced with an identical piece of the same material,

  • until, at some point, no original parts remained.

  • Plutarch noted the Ship of Theseus

  • was an example of the philosophical paradox

  • revolving around the persistence of identity.

  • How can every single part of something be replaced,

  • yet it still remains the same thing?

  • Let's imagine there are two ships:

  • the ship that Theseus docked in Athens, Ship A,

  • and the ship sailed by the Athenians 1000 years later, Ship B.

  • Very simply, our question is this: does A equal B?

  • Some would say that for 1000 years there has been only one Ship of Theseus,

  • and because the changes made to it happened gradually,

  • it never at any point in time stopped being the legendary ship.

  • Though they have absolutely no parts in common,

  • the two ships are numerically identical, meaning one and the same,

  • so A equals B.

  • However, others could argue that Theseus never set foot on Ship B, and his presence on the ship is an essential qualitative property of the Ship of Theseus.

  • It cannot survive without him.

  • So, though the two ships are numerically identical,

  • they are not qualitatively identical.

  • Thus, A does not equal B.

  • But what happens when we consider this twist?

  • What if, as each piece of the original ship was cast off, somebody collected them all, and rebuilt the entire original ship?

  • When it was finished, undeniably two physical ships would exist:

  • the one that's docked in Athens,

  • and the one in some guy's backyard.

  • Each could lay claim to the title, "The Ship of Theseus,"

  • but only one could actually be the real thing.

  • So which one is it,

  • and more importantly, what does this have to do with you?

  • Like the Ship of Theseus,

  • you are a collection of constantly changing parts:

  • your physical body, mind, emotions, circumstances, and even your quirks,

  • always changing, but still in an amazing and sometimes illogical way,

  • you stay the same, too.

  • This is one of the reasons that the question, "Who am I?" is so complex.

  • And in order to answer it,

  • like so many great minds before you,

  • you must be willing to dive into the bottomless ocean of philosophical paradox.

  • Or maybe you could just answer,

  • "I am a legendary hero sailing a powerful ship on an epic journey."

  • That could work, too.

Throughout the history of mankind,

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B2 US TED-Ed theseus identical athens philosophical identity

【TED-Ed】Who am I? A philosophical inquiry - Amy Adkins

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    SylviaQQ posted on 2015/09/06
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