A Reply to the Ship of Theseus

[Doomsought]

Consider a shipyard that is constructing two ships of the same type. Wood from the same forest is used to make both ships. Their sails come from the same weavers. The same pitch seals their hulls. Both ships are identical. Before they eyes of a god, there is not one atom different between the two.

Therefor, I ask you, what makes these two ships different ships rather than a single ship?

 

[Ash's Boomstick]

Logically that is impossible, there is no way for two things exactly the same in every way to exist in nature, even identical twins or cells that have separated can't be completely atomically the same in every way. However given this is a thought puzzle and not based on reality the answer would depend on the point of view of the person looking at it.

Both arguments would be valid due to the simple idea that they are the same thing down to the molecular level, however the moment they are finished they would begin to change simply by existing, different things would happen, for example a seagull lands on one but not the other, one is bumped into by a worker causing a tiny scratch.

 

[Bear Ribs]

The thing about the Ship of Theseus question is that it ignores how humans normally do things. There's typically a specific, critical component that is considered "the thing" and replacing it makes it a new "thing" while replacing all other parts does not.

For instance in a firearm the receiver is the firearm. I can replace the barrel, stock, screws, firing pin, and sight and it's the same firearm, but if I replace the receiver but keep all those, I have made a new firearm.




On a more philosophic basis the issue with the Ship of Theseus is that it presumes ships exist. They don't (no really). We call a collection of atoms a ship for convenience's sake but there's not actually a ship there, just a collection of parts that happen to move in the same direction due to physics. In the same way I can call something the "Mississippi River" and pretend it's the same river that Mark Twain steamed on even though not one drop of water is the same as it was then, the universe does not care that we happen to call one piece of flowing water the Mississipi and another the Nile, it's all hydrogen and oxygen atoms with some other assorted molecules in it. Insisting that the Ship of Theseus exists is like calling a character Bugs Bunny, and then arguing about which drawing in decades of cartoons is the real Bugs Bunny and which of those cells are not the real Bugs. They're all the real thing because Bugs Bunny is an idea that we're attributing some physical reality to even though the reality only exists in our own minds.

Consequently from that point of view it remains the Ship of Theseus so long as "Ship of Theseus" is printed on the bow, and becomes a different ship when those words are erased and "Ship of Hercules" is written there even if all of the parts are the same, because it's only the Ship of Theseus if we agree that this assortment of atoms is called the Ship of Theseus.

 

[Doomsought]

There exists a correct answer, it is valid in a material world, but does not rely on materialism in the way you have attempted.

 

[Bear Ribs]

There does not exist a single correct answer to the Ship of Theseus question. There are numerous "correct" answers proposed through the ages but all of them boil down to what your personal interpretation of "Identity" is and how you choose to identify things in the world. Once you change your assumption on identity the correct answer changes as well.

 

[Captain X]

On a more philosophic basis the issue with the Ship of Theseus is that it presumes ships exist. They don't (no really). We call a collection of atoms a ship for convenience's sake but there's not actually a ship there, just a collection of parts that happen to move in the same direction due to physics. In the same way I can call something the "Mississippi River" and pretend it's the same river that Mark Twain steamed on even though not one drop of water is the same as it was then, the universe does not care that we happen to call one piece of flowing water the Mississipi and another the Nile, it's all hydrogen and oxygen atoms with some other assorted molecules in it. Insisting that the Ship of Theseus exists is like calling a character Bugs Bunny, and then arguing about which drawing in decades of cartoons is the real Bugs Bunny and which of those cells are not the real Bugs. They're all the real thing because Bugs Bunny is an idea that we're attributing some physical reality to even though the reality only exists in our own minds.

Consequently from that point of view it remains the Ship of Theseus so long as "Ship of Theseus" is printed on the bow, and becomes a different ship when those words are erased and "Ship of Hercules" is written there even if all of the parts are the same, because it's only the Ship of Theseus if we agree that this assortment of atoms is called the Ship of Theseus.

This argument doesn't really make sense to me, sorry. It might be getting philosophical, but I think you'd be nearer to the matter if you were going to argue about what makes a specific ship that specific ship. For example, I can make a new ship that is exactly the same as the ship that sailed in 1912, even making it out of the same type of inferior steel and iron, but the real RMS Titanic is resting on the ocean floor, what's left of her. Likewise, people actually do argue about things like fictional characters being "real" or not. Saavik, for example (Kristy Alley vs. Robin Curtis). I even get into it myself with Kei and Yuri from Dirty Pair, as I reject the versions from Dirty Pair Flash. Kind of the same thing with nuTrek as far as rejecting the newer shows and movies. As for the Ship of Theseus argument, it's ironic in that I'm most familiar with it through the themes explored in Ghost in the Shell and its various adaptations. How much of a human can be replaced and still be human? In the 1995 movie, only a few brain cells of the person Motoko Kusanagi was remained. In Stand Alone Complex it was her entire brain. I'd actually argue that the brain is the only organ that can't be replaced while still remaining the same person. Deep Space Nine actually explored that a bit, too, but there's real historical examples of changes in personality and the like resulting from injuries to the brain, like a guy who managed to survive being impaled through the head but was a different person afterwards. The other side of this question in GitS concerns AI: as AI becomes more and more advanced, it may become difficult to distinguish it from a living person. At what point does an AI become a person, if ever?

 

[Ash's Boomstick]

The follow on argument to that is, what happens if that AI copies itself completely. Are they still the same person?

 

[Bear Ribs]

This argument doesn't really make sense to me, sorry. It might be getting philosophical, but I think you'd be nearer to the matter if you were going to argue about what makes a specific ship that specific ship. For example, I can make a new ship that is exactly the same as the ship that sailed in 1912, even making it out of the same type of inferior steel and iron, but the real RMS Titanic is resting on the ocean floor, what's left of her. Likewise, people actually do argue about things like fictional characters being "real" or not. Saavik, for example (Kristy Alley vs. Robin Curtis). I even get into it myself with Kei and Yuri from Dirty Pair, as I reject the versions from Dirty Pair Flash. Kind of the same thing with nuTrek as far as rejecting the newer shows and movies. As for the Ship of Theseus argument, it's ironic in that I'm most familiar with it through the themes explored in Ghost in the Shell and its various adaptations. How much of a human can be replaced and still be human? In the 1995 movie, only a few brain cells of the person Motoko Kusanagi was remained. In Stand Alone Complex it was her entire brain. I'd actually argue that the brain is the only organ that can't be replaced while still remaining the same person. Deep Space Nine actually explored that a bit, too, but there's real historical examples of changes in personality and the like resulting from injuries to the brain, like a guy who managed to survive being impaled through the head but was a different person afterwards. The other side of this question in GitS concerns AI: as AI becomes more and more advanced, it may become difficult to distinguish it from a living person. At what point does an AI become a person, if ever?

You do realize that was my first argument? I pointed out the answers to the Ship of Theseus from the "you can describe one specific part as effectively what it is and everything else is an accessory" and "from a materialist perspective there is no actual ship just a collection of parts." I actually use both viewpoints depending on the situation.

 

[Doomsought]

The answere is history. The uncertainty of the Ship of Theseus is an illusion created by artificially creating a discontinuity in time and separating cause from effect. It is precisely because the changes occurred that it is the same ship. If you build an identical ship, it is still not the same ship because it lacks the history of the other ship. The essence of a thing is the difference between the whole and the sum of its parts.

 

[Bear Ribs]

That would imply that your two ships in the opening post are the same ship until after they actually have some history and have done different things (at which point they are no longer atomically identical to the eyes of god anyway). I don't believe most people would find that conclusion logical.

 

[Doomsought]

That would imply that your two ships in the opening post are the same ship until after they actually have some history and have done different things (at which point they are no longer atomically identical to the eyes of god anyway). I don't believe most people would find that conclusion logical.

The process of being created is part of their history. You can not differentiate them by saying one is different from the other because one is in the first slipway, and the other is in the second slipway, as you can more the ships and have them switch slipways. But when you move it into the past tense it works, one ship was built in the first slipway, and the other ship was built in the second slipway. Making them swap slipways only adds history.

 

[Bear Ribs]

The process of being created is part of their history. You can not differentiate them by saying one is different from the other because one is in the first slipway, and the other is in the second slipway, as you can more the ships and have them switch slipways. But when you move it into the past tense it works, one ship was built in the first slipway, and the other ship was built in the second slipway. Making them swap slipways only adds history.

This presumes that you can tell the slipways apart and so you've only actually moved your position back one remove. You now have to establish that the slipways are distinguishable. Additionally you have to confront the issue that history is information. If nobody can tell the ships apart and nobody can tell which slipway which ship was built in, do they actually have different histories?

 

[Doomsought]

If nobody can tell the ships apart and nobody can tell which slipway which ship was built in, do they actually have different histories?

Time and location exist.

 

[Bear Ribs]

The theory of Relativity tells us that no position, time, or viewpoint is privileged against any other and that all of time and space are relative, not fixed. Therefore you cannot say empirically that any time or position exists except as relative to another. You are using an arbitrary definition based on your fixed viewpoint which is kind of the point of the Ship of Theseus argument.

Put another way if a universe has no matter and no energy, does any time pass in that universe and is there any actual space in it?

 

[Doomsought]

Therefore you cannot say empirically that any time or position exists except as relative to another. You are using an arbitrary definition based on your fixed viewpoint which is kind of the point of the Ship of Theseus argument.

No its not. that is just nonsense. The ship of Theseus is about change.

 

[Zachowon]

The diffrnce is after they are built.
For they may be exactly the same, but to the persons in charge, there may be differences, not physical, but in thier hearts. Let's say both ships remain unnamed after being built, but after a voyage, something happens. The ship is undamaged, nothing changed, but to the crew she earned a name. That is what the diffremce is.
A materialistic change that is. The crew make the diffrence, they make it no longer the same. Wkth a name, adding something on after.
They make it thier own. For both ships may be the same, but will always be diffrenr in the eye of the beholder.

 

[Bear Ribs]

Naw, the Ship of Theseus is about identity and how you can call discrete objects apart from others. Change is the medium of the question but not the actual subject.

Identity, Persistence, and the Ship of Theseus

The traditional followup question to the Ship of Theseus makes that a bit clearer. Suppose that as the Ship of Theseus is gradually replaced, the replacement parts are stored and, later, reassembled into a new ship. Is the new ship the Ship of Theseus or the old?

As @Zachowon says, the answer is always different depending on your perspective and the point of the exercise is to look at yourself and consider how your perspectives affect how you view the world.

 

[Zachowon]

Naw, the Ship of Theseus is about identity and how you can call discrete objects apart from others. Change is the medium of the question but not the actual subject.

Identity, Persistence, and the Ship of Theseus

The traditional followup question to the Ship of Theseus makes that a bit clearer. Suppose that as the Ship of Theseus is gradually replaced, the replacement parts are stored and, later, reassembled into a new ship. Is the new ship the Ship of Theseus or the old?

As @Zachowon says, the answer is always different depending on your perspective and the point of the exercise is to look at yourself and consider how your perspectives affect how you view the world.

It is all about personal ideas in how one can tell apart two identical things. If there is not other way, one must look at themselves and how they would make them diffrent

 

[Bear Ribs]

Incidentally, @Doomsought, the technical term for what you're using to fuel your personal definition is Provenance. I deal with it a great deal in my line of work since I appraise luxury retail goods and have to take the history of an item into account when estimating it's value.

It also somewhat sours my personal perspective on the actual use of provenance since it affects value according to how famous previous owners are, and an item loses it's provenance and value if the chain of custody is ever broken and it can't be proven that said item was involved in historical events anymore, thus is the history isn't known and proof shown, it technically never existed for the purposes of appraisals.

 

[Captain X]

The follow on argument to that is, what happens if that AI copies itself completely. Are they still the same person?

No more than a clone, even with the same memories as the original, would be. It's trickier to say with AI, as it's harder to define exactly what it is, but one of them had the experiences, and the copies only have the memories of them.

You do realize that was my first argument? I pointed out the answers to the Ship of Theseus from the "you can describe one specific part as effectively what it is and everything else is an accessory" and "from a materialist perspective there is no actual ship just a collection of parts." I actually use both viewpoints depending on the situation.

I guess I didn't get any of that from what you said. Going back to the gun example, honestly, pointing to a specific part is just what the ATF does, and there often is very little logical basis in anything the ATF does or how it categories firearms. The amount of an old gun that has been replaced is actually part of what makes it more or less valuable, specifically for the reason that once you start replacing parts, it is no longer the same rifle, it is only mostly the same rifle, except for those parts that have been replaced, and I would even count the receiver among them. As it applies to ships, the closest anyone has come to saying that a specific part represents the entire ship is the ship's bell, and it would be pretty absurd to say that a ship which has had everything but the bell replaced is the same ship, just because it has the same bell.

The other aspect of your argument I didn't get was over the Bugs Bunny stuff, because as I pointed out, people do make arguments like that, and I even gave a couple of my own. I could point to things like writing when it comes to dismissing nuTrek as not being "real" Star Trek, for example, and it would be a matter of whether people agreed with it or not, but the point remains that it is an argument that can be made and does get made.