# Ship of Theseus **URL:** \ **Category:** In My Humble Opinion\ **Created:** [March 27, 2010, 5:28am UTC](https://boards.straightdope.com/t/ship-of-theseus/533998 "2010-03-27T05:28:49Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Autolycus](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@Autolycus](https://boards.straightdope.com/u/Autolycus)\ **Post date:** [March 29, 2010, 7:52am UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/21 "2010-03-29T07:52:23Z")
Have you been playing with lightning in the swamps lately? [Donald Davidson (philosopher) - Wikipedia](http://en.wikipedia.org/wiki/Swampman) I wish I had something more intelligent to say. I just think that’s one cool thought experiment. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [March 29, 2010, 10:50am UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/22 "2010-03-29T10:50:16Z")
This isn’t really a problem of deciding where is the boundary between original and new. Either the gestalt has some emergent property that can have identity, or (more likely, in most cases), it’s just convenient fiction to apply the notion of original identity to something that is a collection of changeable parts. ---
**Author:** ![Autolycus](https://avatars.discourse-cdn.com/v4/letter/a/22d042/32.png) [@Autolycus](https://boards.straightdope.com/u/Autolycus)\ **Post date:** [March 29, 2010, 10:51am UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/23 "2010-03-29T10:51:56Z")
@Mangetout: Huh?! I understand what you’re saying but not 100% ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [March 29, 2010, 1:05pm UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/24 "2010-03-29T13:05:16Z")
> [@Autolycus](#): > > Have you been playing with lightning in the swamps lately? [Donald Davidson (philosopher) - Wikipedia](http://en.wikipedia.org/wiki/Swampman) This is one of the practical issues I have with teleportation: if the actual atoms that make up you are transported and rearranged - like freeze-drying something and then adding water - it seems like it’d work. However, if you do it the way it often seems to be done in sci-fi - creating an identical copy of the original at the arrival site, and vaporizing the other - then the consciousness of the original will cease to exist and the new version will effectively be a new being. Same goes for mind-state copying, such as in Iain Banks novels. ---
**Author:** ![Attack\_from\_the\_3rd\_dimension](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@Attack\_from\_the\_3rd\_dimension](https://boards.straightdope.com/u/Attack_from_the_3rd_dimension)\ **Post date:** [March 29, 2010, 3:47pm UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/25 "2010-03-29T15:47:01Z")
If there were an undersea earthquake near Chile, it might form a tsunami, which would then race across the Pacific and endanger lives and property in Hawai’i. We would worry about the tsunami, and track the tsunami with ocean buoy data. However, the water molecules near Chile remain near Chile. The water molecules are moved, and then move other molecules, so that the waveform moves across the sea at hundreds of miles per hour, but no molecule is part of the Tsunami for more than a few moments. Is it the same Tsunami? ---
**Author:** ![blindboyard](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/blindboyard/32/2833_2.png) [@blindboyard](https://boards.straightdope.com/u/blindboyard)\ **Post date:** [March 29, 2010, 4:13pm UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/26 "2010-03-29T16:13:19Z")
I’d just like this thread to be renamed “Trigger’s Broom”. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [March 29, 2010, 4:24pm UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/27 "2010-03-29T16:24:11Z")
“Stanley Spidowski’s mop”. ---
**Author:** ![Malleus\_Incus\_Stapes](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/malleus_incus_stapes/32/3293_2.png) [@Malleus\_Incus\_Stapes](https://boards.straightdope.com/u/Malleus_Incus_Stapes)\ **Post date:** [March 29, 2010, 5:08pm UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/28 "2010-03-29T17:08:05Z")
If you have one amoeba, and it divides, which is the original amoeba? Both of them. Which is the original ship? Both, but with the properties of originality split between them. One has the property of continuous use, the other has the property of original materials. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [March 29, 2010, 5:14pm UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/29 "2010-03-29T17:14:11Z")
As said by **nachtmusick** , emphasis mine: > [@](#): > > When Captain Kirk beamed down to the planet, the teleporter presumably scrambled his atoms and then re-assembled them on the planet surface. **The laws of physics preclude that the actual substance of his body could be transported in that fashion** , so we must conclude that the transporter dis-assembled him, beamed the information to the planet at light-speed, then the planet’s transporter re-assembled him. That point is disputable. According to some quantum theories, energy can be teleported by quantum entanglement; and if energy can be teleported than in principle so can mass, although it practice you would need to be able to describe mass in purely quantum physical terms, i.e. quantum gravity. This is a different proposition than the classical physics version of a teleporter, which is a scanner/assembler which simply makes a copy of the original in a different place. Yet another example of the Ship of Theseus puzzle was in one of the series of Oz books by Frank L. Baum. If you’ve read the original series of stories, you might recall that the Tin Woodsman was originally a flesh and blood man named Nick Chopper. He became the Tin Woodsman when a series of accidents led to his original body being replaced piece by piece. He survived having his head chopped off and his body split in half only because in the magic Land of Oz no one can die\*. In one of the sequel books (Baum wrote over a dozen) the Tin Woodsman encounters the still-living head of Nick Chopper, leading the Tin Woodsman to wonder just who he is. Nick Chopper’s head is eventually assembled along with other miscellaneous parts (and the help of a pot of “Meat Glue”) into a new person who is not Chopper nor any of his other “donors”. In another book an evil enchantress keeps a closet full of young women’s heads, from which she _ **chooses which head to wear that day** _(!) From multiple other examples in the stories, it’s apparent that in Oz what counts is the continuity of the whole, not any of the components. \*so what happened to the Wicked Witches of the East and West? I dunno. ---
**Author:** ![Stealth\_Potato](https://avatars.discourse-cdn.com/v4/letter/s/d78d45/32.png) [@Stealth\_Potato](https://boards.straightdope.com/u/Stealth_Potato)\ **Post date:** [March 29, 2010, 6:11pm UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/30 "2010-03-29T18:11:00Z")
> [@Autolycus](#): > > Have you been playing with lightning in the swamps lately? [Donald Davidson (philosopher) - Wikipedia](http://en.wikipedia.org/wiki/Swampman) > > I wish I had something more intelligent to say. I just think that’s one cool thought experiment. My personal take is that the Swampman is every bit as much Davidson as the “original” Davidson was. If there is no difference between their current internal states, their respective causal histories are irrelevant. Four is four, whether you arrived at it by adding two and two or taking two from six. Davidson is Davidson, whether he is arrived at by the coincidental arrangement of molecules in biological growth, or by the coincidental arrangement of molecules produced by a lightning bolt. If the lightning bolt that killed the “original” Davidson had instead hit a nearby tree, then we would have _two_ Davidsons. Both causal histories are arbitrary, coincidental, and result in identical individuals named Davidson – one process is merely much slower than the other. So it’s plain that only the ending state is important, and not the causal history. Needless to say, I reject semantic externalism: I believe it is misleading – and a sloppy equivocation – to conclude from the possible re-ordering of a pair of marbles that Davidson could be taken to “mean” either one of them even when his brain state is identical in either case. Davidson’s words have meaning in two distinct contexts, and the meaning of the meaning is different in each: one is his own brain state, and it is obvious that there can be no difference in meaning there, since it is given that there is no difference in Davidson’s brain state between the two scenarios. The other context is the brain state of the person hearing Davidson’s words. And depending on this internal state of the recipient, they may indeed take Davidson’s words as referring to one marble or the other. But this has nothing to do with Davidson’s causal history, nor even the causal history of the listener: it is the _present state_ of the listener that determines the meaning of Davidson’s words in the listener’s context, just as it is the _present state_ of Davidson that determines the meaning of his words in _his_ context. In no part of this is it necessary to consider causal history to determine meaning. ---
**Author:** ![Attack\_from\_the\_3rd\_dimension](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@Attack\_from\_the\_3rd\_dimension](https://boards.straightdope.com/u/Attack_from_the_3rd_dimension)\ **Post date:** [March 29, 2010, 7:36pm UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/31 "2010-03-29T19:36:38Z")
Tin Woodsman Tsunami Amoeba Nobody’s weighed in on these yet. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [March 29, 2010, 7:52pm UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/32 "2010-03-29T19:52:57Z")
A tsunami does not require the molecules from one place to move to another; it is a wave (of energy). ---
**Author:** ![Malleus\_Incus\_Stapes](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/malleus_incus_stapes/32/3293_2.png) [@Malleus\_Incus\_Stapes](https://boards.straightdope.com/u/Malleus_Incus_Stapes)\ **Post date:** [March 29, 2010, 8:13pm UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/33 "2010-03-29T20:13:18Z")
EDIT: I may have been whooshed ---
**Author:** ![Attack\_from\_the\_3rd\_dimension](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@Attack\_from\_the\_3rd\_dimension](https://boards.straightdope.com/u/Attack_from_the_3rd_dimension)\ **Post date:** [March 29, 2010, 9:04pm UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/34 "2010-03-29T21:04:44Z")
> [@Johnny\_L.A](#): > > A tsunami does not require the molecules from one place to move to another; it is a wave (of energy). This is exactly my point. At any moment a tsunami is composed of a bunch of water molecules. A bit later, the wave is made up of a bunch of other molecules. The boat is doing the same thing, as it’s bits get replaced, but it takes longer to turn over all the bits. ---
**Author:** ![FatBaldGuy](https://avatars.discourse-cdn.com/v4/letter/f/ecd19e/32.png) [@FatBaldGuy](https://boards.straightdope.com/u/FatBaldGuy)\ **Post date:** [March 29, 2010, 9:08pm UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/35 "2010-03-29T21:08:58Z")
Continuing with the airplane example, here is a thought problem to ponder. Assume that you have a brand new airplane, fresh from the factory, sitting in a hangar. One piece at a time, you remove every part from the airplane(except for the data plate) and replace it with a new factory original part, and place all of the “old” parts in a pile on the hangar floor. Now, you take that pile of parts and reconstruct it into an airplane. Which is now the original? What if you now move the data plate from the first airplane and attach it to the second one? In this case, it’s not an example of parts replaced for maintenance, but of fully functioning parts being replaced to create a new airplane. I’m guessing that the cost of the parts would be several times greater than the cost of simply buying a new plane, but it could be done. But now, what is the status (both legally and philosophically) of the plane without the data plate? ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [March 30, 2010, 12:05am UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/36 "2010-03-30T00:05:30Z")
> [@Johnny\_L.A](#): > > A tsunami does not require the molecules from one place to move to another; it is a wave (of energy). That brings up something I thought of once that I’ll toss out here. Is a hurricane an event or an object? If you’re down at sea level on a human scale you think of a hurricane as an event: clouds roll in, the wind rises, the waves grow. But if you’re looking down from orbit you see this spiral shaped thing with fairly sharp boundaries relative to it’s size. Which leads me to wonder: in an ultimate sense, can anything be interchangably considered either an object or an event? ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [March 30, 2010, 1:23am UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/37 "2010-03-30T01:23:13Z")
> [@Attack\_from\_the\_3rd\_dimension](#): > > This is exactly my point. At any moment a tsunami is composed of a bunch of water molecules. A bit later, the wave is made up of a bunch of other molecules. The boat is doing the same thing, as it’s bits get replaced, but it takes longer to turn over all the bits. I disagree. A tsunami is created by a wave of energy propagating itself through a medium, much like sound propagates itself itself through the medium of air (or water, or railroad track, or…). The (water) wave itself is caused by wave-shoaling when the (energy) wave reaches shallower water. The (energy) waves that cause tsunami waves isn’t made up of molecules of water, but are traveling through molecules of water. > [@Lumpy](#): > > That brings up something I thought of once that I’ll toss out here. Is a hurricane an event or an object? If you’re down at sea level on a human scale you think of a hurricane as an event: clouds roll in, the wind rises, the waves grow. But if you’re looking down from orbit you see this spiral shaped thing with fairly sharp boundaries relative to it’s size. Which leads me to wonder: in an ultimate sense, can anything be interchangably considered either an object or an event? I say that it’s an event, like a tsunami. Though it appears to be a coherent whole when seen from altitude, it’s actually an interaction of forces. Like, you can’t catch a cyclonic wind in a jar and then let it come breezing out later. You just have a jar of air. ---
**Author:** ![Attack\_from\_the\_3rd\_dimension](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@Attack\_from\_the\_3rd\_dimension](https://boards.straightdope.com/u/Attack_from_the_3rd_dimension)\ **Post date:** [March 30, 2010, 3:06am UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/38 "2010-03-30T03:06:20Z")
If you see a hurricane from altitude, it looks like a coherent whole, but from a perspective on the ground it looks like - chaos, actually - but certainly not a coherent whole the way it looks from above. However, I wonder if the same could not be said of the boat. If I were as long-lived as a sequoia, most boats would come together in a blink, jump in the water and slither around a bit, and then fall to bits. If you leave the plane in a jar for a 500 or a thousand years, you’ll have a pile of rust. I’m wondering if these aren’t all ‘events’, and we’re calling some of them continuously existing things because of our limitations of scale, just a \*\*Johnny L.A. \*\*suggested about the hurricane. Hell, the \*\*Great Red Spot \*\*on Jupiter is a essentially a hurricane that’s been going since at least 1665, and has already outlived most boats. When does it get to be a thing? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [March 30, 2010, 7:55am UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/39 "2010-03-30T07:55:27Z")
> [@nachtmusick](#): > > Related quandary: > > Death by Science Fiction Teleporter. > > When Captain Kirk beamed down to the planet, the teleporter presumably scrambled his atoms and then re-assembled them on the planet surface. The laws of physics preclude that the actual substance of his body could be transported in that fashion, so we must conclude that the transporter dis-assembled him, beamed the information to the planet at light-speed, then the planet’s transporter re-assembled him. The _real_ laws of physics may or may not preclude such a thing. But in the _Star Trek_ universe, transporters convert matter to energy and back - it’s not just _information_ that’s transmitted, it is (supposedly) the substance of the transported object, in energy form. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [March 30, 2010, 2:52pm UTC](https://boards.straightdope.com/t/ship-of-theseus/533998/40 "2010-03-30T14:52:26Z")
> [@](#): > > If I were as long-lived as a sequoia, most boats would come together in a blink, jump in the water and slither around a bit, and then fall to bits. [Das Rad](http://www.youtube.com/watch?v=DT13GuPZHMA) [Previous page](https://boards.straightdope.com/t/ship-of-theseus/533998.md?page=1) [Next page](https://boards.straightdope.com/t/ship-of-theseus/533998.md?page=3)