What is True?

Mad Scientists and the Ship of Theseus: Philosophy Games

Over Thanksgiving, I got to spend some time with my nephews, and I ended up having a philosophy conversation with my preteen nephew, J, about mad scientists, identity, and the ship of Theseus.

I used to be a middle and high school teacher and have always loved preteens and teenagers. I find that when they become interested in a topic, they often have a lot of curiosity and creativity. My conversation with my nephew, which I recorded below, definition showed this curiosity and creativity.

The conversation  was about human identity and what it is that makes us, us. It is a topic very popular in philosophy and has been discussed by luminaries such as Descartes, Locke, and David Hume, as well as contemporary philosophers.

This is my conversation with J, posted with his permission and the permission of his parents.

Nephew: Aren’t you a teacher or something?

Me: I am. I’m a college professor. I teach philosophy.

Nephew: Oh, cool.

Me: You want to play a philosophy game?

Nephew: Okay.

Me: This is something called a thought experiment. Imagine that there is a ship called the Ship of Theseus. Imagine that one day someone comes along and board by board, metal piece by metal piece, sail by sail, replaces every single part of the Ship of Theseus with identical but all new parts. Is it still the same ship?


Nephew: Yes.

Me: Why?

Nephew: I’m not sure.

John (My husband): Watch out. She’s kind of like a philosophical ninja.


Me: Okay, well, let me ask you another question. Imagine a guy name Bob. Let’s say Bob is in a bad car accident, and he loses his arms and legs, and the doctors give him mechanical arms and legs. Is he still Bob?

Nephew: Yes.

Me: Okay, well, let’s say that Bob’s heart stops working and the doctors give him a mechanical heart. So now Bob has a mechanical legs and arms and heart. Is he still Bob?

Nephew: He’s almost turned into a robot. I don’t think he is Bob anymore.

Me: Tell me more about why he became a robot with the mechanical heart but not with the mechanical legs and arms.


Nephew: Well, because your heart is kind of like your soul.

Me: So, it’s your heart that makes you, you?

Nephew: No, it’s my brain.


Me: Why?

Nephew: Because that where all my memories are.

Me: I see, so it’s your memories that make you, you?

Nephew: Yes!

Me: Well, let’s say that a mad scientist sneaks into the house at night and switches your brain with Uncle John’s brain. So your brain is now in Uncle John’s body. Is that you over there? (Me, pointing to John).

Nephew: Yes! This is pretty fun.


Me: Let me ask you another question. Let’s go back to Bob. Say that Bob is in another accident, and he loses all of this memories of his past life permanently. Is he still Bob?

Nephew: No, I don’t think he is because our memories make us who we are. SPo if we lose them, we aren’t ourselves anymore.

Me: Okay, well let’s say Bob gets really drunk one night and hits someone in a car and kills him, but Bob has no memory of doing this. Should we hold Bob accountable? After all, Bob can’t remember the incident, so maybe it wasn’t him who did it.

Nephew: But I think it is still his fault.

Me: Tell me why you think that.

Nephew: Because Bob’s memories will eventually come back. He’s only lost them temporarily.

Me: That’s an interesting argument, J. So it is only permanent memory loss that make us not us anymore?

Nephew: Yes!


What do you think? What makes us, us? Is it our brains? Is it our bodies? If we lose all of our memories, are we still ourselves? Why?

What do you think about the Ship of Theseus? If the Ship of Theseus gets identical but completely brand new parts (all new parts), is it still the same ship? Why?

I would love to hear your comments in the space below.
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16 thoughts on “Mad Scientists and the Ship of Theseus: Philosophy Games”

  1. Interesting…I think there’s a lot of who a person is in how their mind actually works too. You can see it in someone who has dementia. Maybe it’s just the small amount of memory that remains – but it seems to be more than that because you can see that they have their own characteristic way of processing things. Whatever it is, it must run very deep within us!

      1. I really think so. My mother had vascular dementia and even though her memories were gradually disappearing, her personality was still recognisably there. (Obviously much less vibrant and probably only apparent to those closest to her.) There just seems to be some small part of ‘self’ that remains.

  2. Our relationships, the people and things we brush against (or crash into), change and are shaped by… what we salvage from the wreckage, take on board and carry with us on our journey. That’s what I think makes us Us… and no two ships are alike. Wondrous post. – tsk

  3. Some very deep thoughts here – good on your nephew for keeping up with you! That thought about the boat has always been a tough one. I think that there is so much that makes us a part of who we are – even if a lot our “parts” are replaced, there will always be something left – a memory or energy – even if it comes from somewhere else.

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