
Ship of Theseus - BudVVeezer
https://en.wikipedia.org/wiki/Ship_of_Theseus
======
vinceguidry
A thing's identity doesn't reside in the object itself, but rather the person
or persons doing the identifying. Also, identity can be split into elements.
The name, as in "Ship of Theseus," can be swapped out independently of the
elements, though doing so tends to lead to confusion.

The example given of the sock with the hole in it: assume it's the only sock
that the owner has with that hole. If the hole goes away, then it no longer
has a unique identity, it's just another sock in his drawer. What gave it an
identity in the first place was the fact that it was different.

With a ship, its identity appears to be tied to its designation. If you
carried on replacing all the parts of the ship, it'd still be the Ship of
Theseus, because that's what it's called. Back in the day when I owned a
desktop computer, several times this would actually happen. Every component
would got swapped out over a period of time. It carried on being my computer
throughout all of it.

A computer's identity can be arguably split into two main elements, a computer
and a system. If I replace the operating system and wipe all the data, using
it feels completely different. Yet it's the same computer, just running
different software. If you replaced the crew of a ship with a different crew,
then the ship would operate differently, say, in battle, but it would still be
the same ship.

You could restore the old system / crew and retrieve the original
functionality, but if you replaced both the hardware and the 'software', yet
kept the designation, you have two different things with the same name.

A person's body has all of its cells replaced after a period of years. But we
don't go around emptying the prisons of long-serving inmates on the basis that
the person that committed the crime isn't the same as the person currently in
jail.

One can devise conceptions of identity with varying degrees of immutability.
The conundrum makes the incorrect assumption that identity itself is an
immutable concept. It's not.

~~~
fgtx
What I find more intriguing in this article is that whenever I click in the
"Śūnyatā" reference link (by the end of the page) it moves to the column on
the right side.

Would that be the same link or is it a new one?

------
davidw
For a somewhat practical example of such a ship:

"The detachment estimates that approximately 10–15 percent of the timber in
Constitution contains original material installed during her initial
construction period in the years 1795–1797"

[https://en.wikipedia.org/wiki/USS_Constitution](https://en.wikipedia.org/wiki/USS_Constitution)

------
vrp101
There's a wonderful Indian film with the same name which kind of touches on
the subject -
[https://en.wikipedia.org/wiki/Ship_of_Theseus_(film)](https://en.wikipedia.org/wiki/Ship_of_Theseus_\(film\))

I would recommend the movie to the fans of cinema/indie movies.

------
afarrell
Where this question becomes practical is with the Origination clause of the US
constitution. It states that any bill for raising revenue must originate in
the House of Representatives. If the House passes a bill that deals with some
topic, and then the Senate amends it by removing all of its' language and
replacing that language with something else, did that bill still originate in
the House?

See: Sissel v. United States Department of Health & Human Services

~~~
niels_olson
Thanks for posting this. I was about to check out as this being a bit of
philosophy I have no interest in. But, I can see where at least having a name
for the phenomenon makes since in circumstances like this.

------
JoeAltmaier
Works well for code projects too! Is it the same code base, even if all the
lines are rewritten?

~~~
kryptiskt
[http://graydon2.dreamwidth.org/195706.html](http://graydon2.dreamwidth.org/195706.html)

Graydon Hoare about what code he has left in Rust.

------
genericuser
I think of it like a band (Could well apply to a company too) which
occasionally replaces members. So long as they replace few enough members each
time that people can associate it with its previous roster, people will accept
it as the same band.

Even if after 20 years of incremental changes to the band none of the original
members are left it will still be considered by many to be the same band
(although they will all likely lament the loss of such and such member) By
being recognized as the same band it inherits many of the same rights such as
performing the same songs as the previous incarnations of the band (assuming
of course it owns, or pays royalties to the right holders, but that is an
unrelated topic).

However if too many members change at once, or they lose a member whose
presence independently defined the band then people will likely not consider
it the same band.

The identity is a label applied to the set, as the set changes so does the
definition of the label. For the most part assuming members of the original
set do not get placed in different new sets all identifying as the original
label, people will generally accept the label as applying to the new set which
was formed.

I would chalk it up to people being stupid, or language being imprecise. The
alternative seems to be to consider every change to the set to require a new
label and be identified as a new set.

~~~
kylec
The Wikipedia article mentions a band, the Sugababes, that started with three
founding members, but one by one all of them ended up leaving the band and
being replaced. Is it still the same band?

An interesting twist is that the three founding members regrouped and formed a
new band, with the Sugababes still in existence. Which is the real Sugababes?

~~~
Zikes
A band isn't only defined by its members, though. They can have a distinct
sound, a preferred genre, even various brandings and styles that make for a
markedly different performance.

~~~
kazinator
But those attributes are defined by the members. :)

~~~
coldtea
Not really. For bands like the Sugarbabes they are defined by the producers,
session musicians, composers and lyricists.

------
z5h
In order to experience/measure something, you must interact with it. Any
interaction changes both sides. You can't experience the same ship twice.

~~~
defen
That's not really satisfying on a human level, though. I can't take your car
and claim that it's no longer "your" car since some atoms changed.

To generalize, physical identity seems to be an important part of ownership,
so how does that interact with this concept?

~~~
z5h
Just accept unsatisfying, impractical truths, and despite that, allow yourself
to have an illogical intuitionistic sense of things. That's what I do. :)

------
scrumper
Known a bit more prosaically as Trigger's Broom in the UK.

And applies to humans, too, with our continually regenerating cells.

~~~
slayed0
There's a good conversation about this, humans and cell regeneration
specifically, in the movie "Waking Life" (as well as many many other great
conversations about a variety of philosophies)

~~~
scrumper
Is that the animated movie about dreams from ~10yrs or so back?

~~~
scott_karana
That's the one. :)

[https://en.wikipedia.org/wiki/Waking_Life](https://en.wikipedia.org/wiki/Waking_Life)

------
function_seven
The DMV solves this by saying, "The Frame".

Now I don't know what happens if I cut out the left frame rail and replace it,
then cut out the right rail and replace that, then the front sub-frame, then
the rear. Whichever section has a VIN plate riveted to it??

~~~
InclinedPlane
Similarly, the ATF solves this by saying "the lower receiver".

------
fapjacks
It reminds me about the story of a famous Japanese street food vendor, who had
cooked soup out of the same pot for fifty years, every day, never stopping to
clean the pot, because he never stopped cooking soup out of it. When the soup
got low, he just threw in the ingredients it needed to fill the pot again.
According to the story, he had been serving the same pot of soup for fifty
years. Pardon if I have murdered this story, and I have no idea where it comes
from. Just something I read one time, and remembered.

~~~
gohrt
In USA: "marry ketchup bottles"

[http://www.wsj.com/articles/SB961626630107390259](http://www.wsj.com/articles/SB961626630107390259)

------
nanocyber
The answer depends on perspective and subjectivity. If I took the ship across
the ocean last year, and now I take the fully-parts-replaced version this
year, I'm still calling it by the same name. In my mind it is "same", unless I
decide to get especially academic about it. It is both same and not-same. Meh.
Not the most interesting of paradoxes. ;)

~~~
electricblue
Its more interesting when you consider how it applies to living beings. If I
replace every part of a dog with cybernetics, is it still the same dog? At
what point does it stop being the same dog? The brain? The nervous system?
Other various senses? How much of identity is tied up in how a creature
perceives its environment? What happens to the creature when we alter that
perception or enhance it?

~~~
jheriko
is identity even real? such thinking can be construed as a 'reductio ad
absurdum' argument that it is not...

how can we even tell if it is a concrete concept? its very poorly defined to
begin with too...

~~~
TeMPOraL
I'd guess it's about as real as most other concepts we use - fuzzy at the
borders and breaking down when you focus on them too hard. It's like asking
when a chair stops being a chair - when it has 3 legs? 2 legs? When it's
angled 45 degrees? 30 degrees? Etc.

I suspect that identity is just another way of grouping things by properties,
in this case including sharing spatial and temporal history - I am the same I
was 10 minutes ago, because I'm made mostly of what I was made 10 minutes ago,
and I moved somewhat continuously through space, etc.

~~~
jheriko
yeah, it falls out of how the brain functions i think... there are a bunch of
classifiers in there, and its not always easy to map what they do to
reasoning. there are loads of fuzzy concepts like this with day-to-day utility
which are very difficult to define accurately in a way that unambiguously
communicates intent to another person.

------
AnimalMuppet
As Paul Graham pointed out in his essay on philosophy, it depends on your
definitions. Here, it depends on your definition of "same". But that makes it
a much less interesting discussion about different (mostly unstated)
definitions of the word "same", rather than a profound philosophical
discussion about something...

~~~
coldtea
No, it's obviously still a profound philosophical discussion about identity.

Saying "it depends on your definitions" sidesteps the whole issue of how you
come to these definitions, and what impact they have on how we view reality.
In other words, it hides the profound issues under the rug.

For example, a common argument against moving your brain information to a
robot as a way to "live forever", is that then it's no longer you (since your
physical brain ceazes to live).

The Ship of Theseus sidesteps this argument, since an example of it would be
replacing your neurons one by one with artificial ones -- with you awake.

With such a procedure, you feel exactly the same at all times, and you have no
recourse to saying your personality was merely "transfered".

It feels like you were the physical person X, and after these steps, you were
the same person with a robotic brain, but with no abrapt change or loss of
consciousness, just a continuous process.

~~~
AnimalMuppet
All right, let me put it this way: There may be a profound philosophical
question about identity. However, because of the problems of the differing,
unstated definitions of "same", almost all of the discussion is really about
the assumed definitions of words, and is therefore almost completely a waste
of time. It _appears_ to be about the profound philosophical question, but
it's mostly not.

~~~
coldtea
It still is profound whatever one's definition of same. Pick a definition of
same. Make it as precise as you want. It might be totally compatible with some
of those definitions you come up with. For all others, The Ship Of Theseus
still makes a powerful questioning tool that raises insights to question those
"single, precise" definitions.

There's a naive (mostly anglosaxon/empiricist) idea that philosophy is just
noise because of the conflicting definitions of things.

Whereas it's the total opposite: questioning and disecting the definitions we
use (and what they presuppose), is the exact role of philosophy.

The Ship of Theseus (and countless others ideas and paradoxes) are tools in
questioning those beliefs and "definitions".

Those examples don't stem because of our confusion about what is same -- they
are tools to probe what we consider same, to poke holes in our idea of
sameness.

And I call the objection to this naive, because having a "single objective
definition" is not something possible (like science doesn't claim to know some
ultimate "reality", just to make ever better models and approximations of it).

We have to live with various ideas about identity/sameness, and we need
philosophy and arguments like The Ship, to question them and see their partial
nature.

~~~
AnimalMuppet
I don't think there's a "single objective definition". There are multiple
valid definitions. What I'm saying is that most of the discussion about The
Ship Of Theseus is really discussions about the definition of "same", but most
of the time, people don't realize that that's what they're arguing about. This
means that most of the argument is wasted time.

Sure, have a discussion about different definitions of sameness. (Ironic,
that.) Poke holes in the various definitions. That's fine. Just don't have
conversations where two different people have different implicit definitions
of sameness, and each sees the other's position as clearly stupid, because the
other person is using an unstated, but different, definition of "same".

~~~
coldtea
> _Just don 't have conversations where two different people have different
> implicit definitions of sameness, and each sees the other's position as
> clearly stupid, because the other person is using an unstated, but
> different, definition of "same"_

As you say, discussing X while having 2 different ideas of X is obviously
wrong -- people practically talking past each other.

But that's only if the discussion is not philosophical but just a practical,
everyday conversation.

That's because in the latter people talk and talk about X while X goes
unexamined, where the essense of a philosophical conversation is to examine X,
and investigation how each one defines it, and what might be correct or wrong
about any singular definition.

A non-philosophical discussion would be: \- X song is the same as Y, they
stole it. \- No it's not, they just have the same chord changes. \- They
should come out with their own, they're copycats.

Whereas a philosophical disussion would be in the vein of: "what is sameness?"
(itself), "when we can say that a song is stolen from another?" etc.

------
jboggan
The best enunciation of this was the opening scene of John Dies At The End:
[https://www.youtube.com/watch?v=O-W_P7rMQRA](https://www.youtube.com/watch?v=O-W_P7rMQRA)

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chrisbennet
It has been said that every cell in your body is replaced every 7 to 10 years.
This is not actually true, since brain cells aren't replaced but if it was, we
would all be "Ships of Theseus".

------
platz
Is the ship a reference object or a value object?

