# The Ship of Theseus



## Claudiu (Apr 28, 2010)

Is there an answer to the Ship of Theseus dilemma? 
The story is: In ancient times, there was a ship, called the "Theseus" after its famous former owner. As the years wore on, the Theseus started getting weak and creaky. The old boards were removed, put into a warehouse, and replaced with new ones. Then, the masts started tottering, and soon they, too, were warehoused and replaced. And in this way, after fifty years, this ship now has all new boards, masts, and everything. The question then arises: Is the ship in the harbor, now called S2, the same ship as the ship that was in the harbor, fifty years ago (called S1, for convenience)? In other words, is S2 really the "Theseus"?

The same can be said about a chair, for example. Let's say that we have a chair and one of the leg breaks off, we then replace the leg with a new one. Over time, though, another leg breaks, and then the backrest, and so on, until there comes a time that the chair in front of us has none of the parts from the original because the parts were replaced. 

As an aside:

Then, there is the Perdurantism vs. Endurantism debate. On top of that, humans are also brought into the picture. 

Lastly, even religions come down to this, as far as humans go. The Buddhists hold to the notion, or rather, doctrine of "No-Self," while in the West, due to the Judeo-Christian context we hold to the "Self" being the same throughout time (when judgment will come it will be on the person [the whole person, from day one to his last breath will be counted, meaning he was the same person throughout all his life]).

The human part seems straight forward to me, that we are the same throughout time. This is where the Buddhist doctrine falls apart because of their belief in Karma, the problem arises on who does the Karma "catch up" with, since there is no self. 

However, I just want to keep it to the basic Ship of Theseus example. In this scenario what would you guys say, that S2 is the Theseus or not? If it is not, then at what point did it become so? (was it after 50% of the original Theseus wood was replaced with the new one that it stopped being the Theseus)?


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## Grymir (Apr 28, 2010)

Is the Ship Theseus more than the sum total of its parts?


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## Philip (Apr 29, 2010)

Why posit S2 at all? There is only S1. Is the ship more than just its boards and nails? If so, then S1 and S2 are the same.


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## jwright82 (Apr 29, 2010)

This sort of problem is what attracted me to the later Wittgenstien's views of language. The erlier Wittgenstein would have said that the name Thesus pictures or models the reality of the ship. Thus there is a problem. The later Wittgenstien said that the meaning of a word is in how it is used. If we apply this view to your problem than the word Thesus can be applyed to the new ship regardless of whether or not the old wood is on there because the word is not absolutly connected to reality in such a way that it can only picture or represent the ship that was the old wood. The word is used to name the ship, we can make all sort of changes to the ship but as long as we still use the same name to name the ship than the the problem goes away. There are many metaphysical problems that can be swept away do to Wittgenstien's later philosophy.


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## Kiffin (Apr 29, 2010)

It's not in the harbor. They found Ship of Theseus in Turkey. Look here http://www.puritanboard.com/f60/noahs-ark-found-turkey-if-so-how-will-impact-genesis-debates-60320/ 

Sorry, couldn't help it..


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## louis_jp (Apr 29, 2010)

I say it's the same ship, simply because of its continuity in history. When a new board is placed on the ship, it takes part in the identity of the ship. When another new board is placed, it joins the whole ship, not an old part and a new part. It's one ship. Eventually all the boards will be "new" and will have participated in varying degrees in the history of the ship, but collectively they maintain continuity with the ship in its history and identity as it always existed. The same thing applies to people.


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## VictorBravo (Apr 29, 2010)

Reminds me of dealing with the City of Tacoma back before they revised their permitting system. I had an attached garage that was crumbling. The permit guy said I needed to pay a demolition permit and then needed to go through plans review in order to rebuild it. The fees would amount to thousands of dollars.

But then he looked over his shoulder and quietly said, "look, you don't need a permit to repair a wall or a roof. What I'd do is just repair the whole thing, one wall at a time. Just make sure you have three walls standing at any time and some original timber still in place, and it's a repair. Just don't tell anybody I said this, but it's our unwritten policy."

So, after a summer of selectively and carefully removing and replacing one wall at a time, and keeping what few good 2X4s that were there, I had a completely new garage. The City was happy with the improvement and, as far as they were concerned, it was the same old garage, just "fixed."

But you can't do that now. They require a permit for almost everything.

Oh, and by the way, I got to know the permit guy personally and he gave me permission to tell the story because he's retired.


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## py3ak (Apr 29, 2010)

This might be simplistic, and I don't know how good the science is, but I have heard more than once that every cell in the human body is replaced over the course of 7 years. _Materially_, then, if that's true you are not the same body you were in 1994, say. But _formally_ you are, because the interchangeable aspect of you (your molecules) is organized in largely the same way; and also, perhaps even more importantly, because there is continuity.

So the _Theseus_ is still the _Theseus_, albeit maintained, just as you are still you, albeit matured.


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## MW (Apr 29, 2010)

Human beings also have consciousness and cognition besides physical likeness. For an inanimate object like a ship, its identity is based on human attribution. As far as human attribution is concerned, the ship has a continuous time-space succession so that it must be identified as the same ship. This is made clear in the scenario, in which the vessel is described as having been completely renovated over a period of time. If a person were to log the changes the gradual transformation would form a series of predications which are unified by one single subject.


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## Skyler (Apr 29, 2010)

Suppose the ship is broken in half and a new half is added on to the old one to repair it. Is it still the Theseus?

What if the other half is salvaged and also repaired? Is that half also the Theseus? And would we then have two Theseuses(Theseii?)?

The answer would seem to be intuitively "no", if the second half is salvaged and repaired after the first; but what if both halves are repaired at the same time? To me, my intuitive response is "neither". Why the difference?

I realize it could be because my intution is faulty, but it's an interesting dilemma.


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## Grymir (Apr 29, 2010)

Of course, the old lumber was broken and rotten when it was taken off, so one would be unable to assemble the warehoused ship anyway...

...I'm just sayin


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## MW (Apr 29, 2010)

Skyler said:


> Suppose the ship is broken in half and a new half is added on to the old one to repair it. Is it still the Theseus?


 
You then have two entities. This seems to me to defeat the philosophical function for which these kinds of scenarios are provided -- being and becoming, one and many.


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## Skyler (Apr 29, 2010)

armourbearer said:


> Skyler said:
> 
> 
> > Suppose the ship is broken in half and a new half is added on to the old one to repair it. Is it still the Theseus?
> ...


 
But I think it's useful to probe the limitations of a scenario. This seems, to me, to be a weak point--how much of an entity can be removed before it ceases to be the same entity?


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## MW (Apr 29, 2010)

Skyler said:


> But I think it's useful to probe the limitations of a scenario. This seems, to me, to be a weak point--how much of an entity can be removed before it ceases to be the same entity?


 
Positing division undermines that question because it is no longer an entity but two entities. There is no ONE in relation to which the MANY is examined. A scenario of diverse entities is not going to help arrive at the idea of essence since it creates another grouping of diversity.


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## Herald (Apr 29, 2010)

What if the obsolete wood from the S1 are burned and the ashes mixed with pitch and used on the S2? (I wonder how far we can go with this)


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## Wayne (Apr 29, 2010)

You might as well posit that the ship was in the trees before they were cut down.


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## Wannabee (Apr 29, 2010)

It is the same ship though the ship isn't the same.


My great-grandfather saw the Salt River flow through the Phoenix valley freely at one time, with no dams to slow it's flow and no gates to keep it going. When I came along the dams controlled it and there was rarely water flowing. When there was water flowing, it was different water. Is it still the same Salt River, even though the Salt River is not the same? He saw the Sitgreaves National Forest too, but those trees died before I saw them. Was it the same forest though the trees were different? Again, it was the same forest, but the forest wasn't the same.

From the mind of a simpleton... sorry, no big words.


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## Grymir (Apr 29, 2010)

One can almost see them talking about Theseus's Ship.


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## Grymir (Apr 30, 2010)

That picture does have alot to do with the Ship.

Here's a link. Scoll down about 1/4 to find out more than is needed. 

Relative Identity (Stanford Encyclopedia of Philosophy)


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## Tim (Apr 30, 2010)

In order to answer this question, do we not first have to establish what is the essence of "Theseus-ness"? Anyone want to try?


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## Backwoods Presbyterian (Apr 30, 2010)

Wannabee said:


> It is the same ship though the ship isn't the same.
> 
> 
> My great-grandfather saw the Salt River flow through the Phoenix valley freely at one time, with no dams to slow it's flow and no gates to keep it going. When I came along the dams controlled it and there was rarely water flowing. When there was water flowing, it was different water. Is it still the same Salt River, even though the Salt River is not the same? He saw the Sitgreaves National Forest too, but those trees died before I saw them. Was it the same forest though the trees were different? Again, it was the same forest, but the forest wasn't the same.
> ...


 
Good to see you and Grymir posting again.


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## Steve Curtis (Apr 30, 2010)

Skyler said:


> how much of an entity can be removed before it ceases to be the same entity?


 
Not addressing the philosophical aspect, I seem to remember the US Treasury maintaining that anything more than 50% of a bill was valid currency. So, in your example, if two equal halves from two different ships were fused, the result could rightly be called the "new" one of either (or both).

As to the philosophical aspect, I believe that this is a retelling of Heraclitus' phrase that "the same man never steps into the same river twice." So the conundrum has been around for 2500 years (at least). As for ships (and other 'things'), I would say that the answer lies in the continuity of form and function. As to persons, I think there is much more involved (i.e., consciousness). Our consciousness is not composed of molecules that are replaced, though our physical body is, of course.

The origins of the Tin Man of Oz are similarly interesting. In the original book, a cursed axe chops off each limb which was subsequently replaced by a tin appendage. Eventually, he is wholly replaced (except for the heart, ergo his part in the movie!), yet he maintains his conscious identity. I know, not formal philosophical argumentation, but interesting, nonetheless.


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## Skyler (Apr 30, 2010)

armourbearer said:


> Skyler said:
> 
> 
> > But I think it's useful to probe the limitations of a scenario. This seems, to me, to be a weak point--how much of an entity can be removed before it ceases to be the same entity?
> ...


 
But how is that different from positing that a piece of the entity (say, the mast) breaks off? You then have two entities, the hull and the mast.


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## jwright82 (Apr 30, 2010)

Skyler said:


> armourbearer said:
> 
> 
> > Skyler said:
> ...


 
Really all you have is two seperate things that you use two seperate words to name, that is all. This whole problem is just a linguistic one and it assumes that a word or idea is attached to one thing in reality, the ship or mast. And since it must be attached or correspond to that thing and only that thing you have problem if all the old stuff is replaced in time and space with new stuff. Now the problem is how can this word or idea correspond to the new stuff when it must correspond to the old stuff? So all these metaphysical gymnastics result from trying to figure out a solution to the problem. 

If we reject this assumption than the problem pretty much goes away. I can use the name "ship of Thessus" to refer to that particular ship in the harbor at lets say dock 1. As long as the community I am a part of also uses the name in the same way than there is no problem. If the ship brakes in half and the two halves are used to make two different ships than all I have now is the "ships of Thessus".


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## Philip (Apr 30, 2010)

James, your solution, as intriguing as it is, fails to grasp the real conflict in the puzzle. The conflict is between maniac particularism and common sense. It makes no more sense to say that the _Theseus_, after having every board replaced, is a new ship than it would to say (with the monist) that the ship and the water are ultimately the same. Both are equally silly and result from too much emphasis on one aspect over the other. Words do, in fact, attach to objects in reality. The problem is not, as you and Wittgenstein would maintain, linguistic. It isn't simply that the community declares "this ship is the _Theseus_:" it's that the particularist is maintaining that whole is simply its constituent parts.


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## MW (Apr 30, 2010)

Skyler said:


> But how is that different from positing that a piece of the entity (say, the mast) breaks off? You then have two entities, the hull and the mast.


 
In this scenario it is possible to speak of an entity and a property rather than two entities; that is a classical way that the many would be related to the one. Thus the illustration serves its purpose. In a scenario where there is division of the ship itself, there is nothing to explore in relation to the one.


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## jwright82 (May 1, 2010)

P. F. Pugh said:


> James, your solution, as intriguing as it is, fails to grasp the real conflict in the puzzle. The conflict is between maniac particularism and common sense. It makes no more sense to say that the _Theseus_, after having every board replaced, is a new ship than it would to say (with the monist) that the ship and the water are ultimately the same. Both are equally silly and result from too much emphasis on one aspect over the other. Words do, in fact, attach to objects in reality. The problem is not, as you and Wittgenstein would maintain, linguistic. It isn't simply that the community declares "this ship is the _Theseus_:" it's that the particularist is maintaining that whole is simply its constituent parts.


 
Good point, but Wittgenstein and I would both say that words do a connection to reality it is just not an absolute one. The community can use words to refer to anything they like as long as they all agree. I agree with your critique of the particularlist and the monist. All I am saying is that this so called metaphysical problem isn't a metaphysical problem at all. It is a mistake on many grounds, a linguistic one being the primary cause of confusion in my opinion.


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## Claudiu (May 1, 2010)

armourbearer said:


> Human beings also have consciousness and cognition besides physical likeness. For an inanimate object like a ship, its identity is based on human attribution. As far as human attribution is concerned, the ship has a continuous time-space succession so that it must be identified as the same ship. This is made clear in the scenario, in which the vessel is described as having been completely renovated over a period of time. If a person were to log the changes the gradual transformation would form a series of predications which are unified by one single subject.


 

I think you pretty much nailed it. That's what I've been thinking about. The problem with most philosophy/science these days is that things are reduced to mere materialism in the case of humans. But humans are more than material, there's the conscious aspect and cognition as you mentioned.

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kainos01 said:


> Skyler said:
> 
> 
> > how much of an entity can be removed before it ceases to be the same entity?
> ...




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Grymir said:


> That picture does have alot to do with the Ship.
> 
> Here's a link. Scoll down about 1/4 to find out more than is needed.
> 
> Relative Identity (Stanford Encyclopedia of Philosophy)


 
Thanks for sharing this. I was looking for an article similar to this one.

---------- Post added at 08:13 PM ---------- Previous post was at 08:13 PM ----------

Thank you all for the input.


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## Philip (May 2, 2010)

jwright82 said:


> Good point, but Wittgenstein and I would both say that words do a connection to reality it is just not an absolute one. The community can use words to refer to anything they like as long as they all agree. I agree with your critique of the particularlist and the monist. All I am saying is that this so called metaphysical problem isn't a metaphysical problem at all. It is a mistake on many grounds, a linguistic one being the primary cause of confusion in my opinion.


 
No, it's not the primary cause. In fact, the US has such a ship: the USS _Constitution_. If we were able to resurrect a sailor who fought on it during the War of 1812, he would recognize it as the _Constitution_ even though most of its constituent parts have changed. It is indeed a metaphysical problem that has little to do with language.


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## jwright82 (May 2, 2010)

> No, it's not the primary cause. In fact, the US has such a ship: the USS Constitution. If we were able to resurrect a sailor who fought on it during the War of 1812, he would recognize it as the Constitution even though most of its constituent parts have changed. It is indeed a metaphysical problem that has little to do with language.



How exactly is it a metaphysical problem? I laid out the analytical view of language and why this is a problem based on those assumptions of language and ideas. If you adopt a late Wittgenstien view of language than the problem disapears, thus it is a linguistic problem. Are their metaphysical elements to this, yes but the problem goes away when we change our view of language. How essences work and all that is ametaphysical problem as far as names are concerned it is only a linguistic problem. I don't see how the problem doesn't go away when we adopt a different view of language?

---------- Post added at 04:36 PM ---------- Previous post was at 04:34 PM ----------

How is it a metaphysical problem? If the problem goes away when you change your assumptions about language than that in my mind makes it a linguistic. How would the problem again come up in a later Wittgenstien view of language?


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## Philip (May 2, 2010)

> How essences work and all that is ametaphysical problem as far as names are concerned it is only a linguistic problem. I don't see how the problem doesn't go away when we adopt a different view of language?



But names signify essences---we are discussing essences, not mere names. Wittgenstein would say that essences _are_ mere names used in a particular community's language-game.


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## jwright82 (May 3, 2010)

P. F. Pugh said:


> > How essences work and all that is ametaphysical problem as far as names are concerned it is only a linguistic problem. I don't see how the problem doesn't go away when we adopt a different view of language?
> 
> 
> 
> But names signify essences---we are discussing essences, not mere names. Wittgenstein would say that essences _are_ mere names used in a particular community's language-game.



Names can be used to signify anything at all. The particular name under discussion is "ship of thessus", which in order to be meaningful only has to refer to some object in reality or memory. This particular name has full meaning if it refers to that ship in the harbor at peir 1. The meaningfullness of word doesn't go away if we have renevated the original boat because everyone in the community uses the same way. If you wnated to talk about essences in general, if there is such a thing, than that is fine but the OP was over the atteachment of the name to the object and a linguistic mistake was made and that is why, in my opinion, the problem arose.


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