The Ship of Theseus is a thought experiment first posited by Plutarch in Life of Theseus. It goes a little something like this:
A ship goes out in a storm and is damaged. Upon returning to shore, the ship is repaired, with parts of it being replaced in the process. Again and again the ship goes out, and again it is repaired, until eventually every single component of the ship, every plank of wood, has been replaced.
Is the repaired ship still the same ship that first went out into the storm? And if not, then at what point did it become a different ship?
Now, say you collected every part of the ship that was discarded during repairs, and you used these parts to rebuild the ship. With the two ships side-by-side, which one would be the true Ship of Theseus? Or would it be both? Or neither?
There’s no single answer to the problem, no correct one, just the looming question: what is the intrinsic thingness of a thing? But the thought experiment has captured my attention because, even though it is thousands of years old, it’s still relevant today. It’s given me a new way to look at some of my favourite bits of pop-culture, some of the technologies used in science fiction, and by extension, a valid frame by which to look at some of the technologies we may be using in the future.
Mad Max: Fury Road opens with Max overlooking a vast dead vista, with only his haunting memories and Ford V8 Interceptor for company. The car will be familiar to anyone who’s watched any of the Mad Max films—it’s served Max across the decades, and across countless miles of post-apocalyptic desert road. But while Max is busy trying to outrun his memories, something else catches up to him—a War Boy patrol. In attempting to flee, Max’s car is wrecked, flipping side over side, coming to a stop on its roof, chassis mangled, axles likely bent or broken, engine mounts the same.
We cut ahead some indeterminate time later, and Max has been turned into a blood bag for ailing War Boys. Strapped to the front of a pursuit vehicle, Max spies something familiar beside him: the Ford V8 Interceptor.
The Interceptor has been rebuilt—the rear suspension has been raised up, Max’s extra fuel barrels have been removed to make space for weaponry, and the paint job has been cut back to bare metal for that “shiny and chrome” look. Still, Max sees his car in this altered beast—whether it’s the long sweeping shape of the coupe’s body, or in some other, indefinably spiritual aspect of the vehicle. Or perhaps Max simply knows he’s dead without a car, and the rebuilt Interceptor is a familiar set of wheels—any port in a storm.
For another example of the Ship of Theseus paradox from the same film, take Furiosa. Her left arm ends just below the elbow, and for much of the film she wears a prosthetic made from metal—but at no point does the film suggest that the intrinsic nature of Furiosa is defined by this prosthetic limb. Scrapping in the dirt with Max upon their first meeting, Furiosa’s prosthetic arm hangs from the side of the War Rig, but she is in no way hindered by its absence, fighting brutally to protect the women under her charge. This might sound obvious—of course Furiosa is just as fierce, just as much herself with or without the arm—but things aren’t always so clear.
In Return of the Jedi we see the Ship of Theseus rear its much-repaired face yet again. Luke Skywalker and the Force ghost of Obi-Wan Kenobi debate the humanity of Anakin Skywalker/Darth Vader, and in making his point, Obi-Wan states that Vader is beyond redemption because he is “more machine than man.” Whether it’s simply the loss of Anakin’s biological body, or some other change that has happened to the man, Obi-Wan sees Darth Vader as a different person, separate from Anakin Skywalker. As far as Obi-Wan is concerned, too many planks in the Ship of Anakin have been replaced. Luke argues otherwise—that despite the fact that Anakin has lost his limbs and needs to rely on a life-supporting suit of armour, he is at heart, the same man.
Now, Luke himself lost a hand at the end of Empire Strikes Back, and had it replaced with an organic-looking robotic prosthetic, but Obi-Wan doesn’t appear to have any issues with the altered Luke. So apparently, according to Obi-Wan, somewhere between replacing a single hand and replacing four limbs, a person may cease to be their true self.
In Altered Carbon, the society and justice system seem to hold that a person’s digitised consciousness—which is able to be swapped between bodies for a price—is their true self, regardless of what body it may be sleeved inside. Even so, within the world of the book (and television series), there is a Catholic sect that holds that a person’s soul cannot be digitised, and as such, after the death of the original body, a person cannot truly be shifted between bodies—that despite a consistent personality and memories, the person’s soul is not present, and without a soul it is not the same person.
Say I had a heart transplant. Would the presence of that foreign tissue somehow alter who I am? Would I be somehow less “myself,” whatever that means? Or, if a person uses a prosthetic limb, which self is more “them”: the self with four limbs, one of which is prosthetic, or the self with three limbs? I would argue that in terms of a person’s essence (again, difficult to define, but the thing that makes you you), there is no difference. I think that no matter the changes made to a person’s body, if their mind is still functioning in whatever is their own version of “normal,” then they would remain their intrinsic self. Anakin Skywalker became Darth Vader because of his choices, not because of an arbitrary amount of flesh being replaced with machine parts (which is likely the argument Obi-Wan meant to make, but is not the one he actually made).
Now, what if we take this problem into the future. How would an uploaded digital consciousness fare against the Ship of Theseus problem? If my mind was recreated perfectly in a digital format, would it in fact be me? What if my fleshy meatsack self was still alive? Would that change your answer? What if me, in this current body had to argue with my digitised self to decide which me was the real me? Is that a debate I could win? Is that a debate that either of me could win?
What about teleportation? If my body was broken down at Point A and transmitted instantaneously to Point B where it was reconstituted, is the person at the other end still me? Or is it some new person who simply looks like me, acts like me, and indeed believes itself to be me? If the me at Point A and the me at Point B are indistinguishable from one another, then does it matter? If you believe in the concept of the human soul, then can the soul also be broken down and reconstituted post-teleportation? Or does it travel the distance itself in its own unknowable way? Or is the person at the other end a soul-less recreation of the original, now dead, person? And most importantly—how would you know?
What about clones? We’ve been able to clone sheep and other animals for a while now, but what if you cloned a human embryo, and brought both embryos to term? Even if you raised both children as if they were identical twins, would one somehow be lesser than the other? If the clone lived as their own person, would they still be a hollow recreation of the ‘real’ person born from the original embryo, or would they be a person with their own intrinsic, indefinable nature? I’d argue that each Ship of Theseus was the real Ship of Theseus, and each was also something else.
Lastly…what makes you you? Is it your body? If so, what happens when you grow older and things don’t work quite as well as they used to? Is it your memories? If so, what happens when some of those memories fade? Is it entirely arbitrary? Is it somehow indefinable? In what ways could you be altered and changed without it affecting your inherent sense of self? These are the sorts of existential questions that philosophy has me thinking about. Thanks, philosophy.
Shows like The Good Place, Westworld, and Black Mirror make it obvious that they’re posing philosophical and metaphysical questions to the viewer— but if you start looking you’ll find various philosophical conundrums hiding in all sorts of places, giving your favourite bits of pop-culture whole new layers of meaning and depth. Where else have you found philosophical paradoxes hiding (or not) in pop-culture? And what other examples of The Ship of Theseus have I missed?
Note: I have to give credit (blame?) where credit is due: my entire philosophical education is the result of watching The Good Place, and reading the work of Damien Williams and m1k3y. If you also want to occasionally trigger an existential crisis while thinking too deeply about science fiction, and also delve deeper into philosophical concepts without hurting your head too much, I highly recommend you check them out.
Corey J. White is a writer of science fiction, horror, and other, harder-to-define stories. He studied writing at Griffith University and is now based in Melbourne, Australia. Killing Gravity and its sequel, Void Black Shadow, are available from Tor.com Publishing. Find him at coreyjwhite.com and on Twitter at @cjwhite.
Obligatory Pratchett, from “The Fifth Elephant”:
A classic example is that an army regiment that replaces all it’s troops over the years is still the same regiment.
The human body changes all the time, cells die and are replaced, I would guess everything we are ‘born with’ has changed many times over by the time we die. So isn’t the question asking if we are the same if an entire part gets replaced a mute point?
Another thing, don’t you think it is a different thing all together when comparing the changing of Luke’s hand to the rebuilding of Max’s car? Are you suggesting our bodies are nothing more than a machine, that the ‘real’ us is just using it for transportation?
Obi-Wan’s problem with Anakin goes a LOT deeper then body parts. In what I consider one of the best parts of the 3 prequel films, Obi-Wan is clearly disturbed by what he has been forced to do to Anakin, a person who he views as his brother and savior of the Galaxy. I think he tells Luke “more machine than man.” as an easy way of expressing how emotionally hurt, even after decades have passed, he is over the entire thing.
It is my firm believe that all things change, nothing stays the same so the entire question is irrelevant.
For an actual “Ship of Theseus” in the USA, there’s USS Constellation, now moored in Baltimore harbor. The “original” Constellation was a frigate built in 1797 and was broken up in 1853. Some of its timbers were then used to build a “new” Constellation, a sloop-of-war, that was launched in 1855. As an historical display, the ship was “restored” to its 1797 appearance in the 1950’s, and there’s been some controversy over the years as to whether it’s really a 1797 ship, or an 1855 ship made to look like a 1797 ship.
Identical twins are natural clones.
The ship is just a different version of Heraklit’s panta rhei.
As I recall there was a short story by either Clarke or Heinlein featuring a character that owned a cigarette lighter. He replaced parts as they wore out, but kept the originals. When he had replaced all the original parts, he reassembled them. Now he had the lighter that he’d been using continually, and the lighter made from the original parts. Which was “his” lighter? He didn’t answer the question, but apparently performed this act specifically in order to ask it.
Identical twins are, in fact, clones by definition. No legal system considers them one person that I know of.
On the other hand, conjoined (“Siamese”) twins grade into being one person. If they’re joined at the chest, two people. If “they” share a single brain, legally one person, right? There’s no sharp distinction.
Ghost in the Shell (the manga/anime, not the vaguely-racist movie) centres on Motoko Kusanagi, whose body was destroyed in an accident when she was a child. Everything short of her brain was replaced by a (child-sized) prosthetic (gradually upgraded as she “aged” into adulthood), and soon even her brain was fully cyberized –just a hard-drive running her consciousness as a program. By the time of the series, transferring herself into new bodies (when the old one is damaged) is a routine outpatient operation.
And yet, she has a “Ghost” –a continuous, unquantifiable soul that AIs, even the sometimes-alarmingly “human” Tachikomas, aren’t considered to have. Unless the Ghost is something far more subtle and emergent than the human characters think, as the anime itself seems to imply.
I remember sticking a story up on a forum a few years back, the story’s thesis being that there is a tipping point. Needless to say, crossing that tipping point resulted in the dreaded ‘Theseus Syndrome’. Original or wha’?
There is Star Trek canon of some flavour that presents a group of people who will not teleport because of philosophical reasons. They might even be presented as post catholic I recall. Isn’t this also a plot point in one of the original or NG episodes?
But, funny. I’ve been mulling over this ever since the original Star Trek. Who says genre fiction makes you dull?! Who needs a classical education when you have, for example, Dr. Who?
@7/Carl: In Cornelia Funke’s children’s novel Potilla, the fairy queen Potilla considers identical twins “a monster with two bodies”. She calls such a creature a “Doppling” (doubling).
@10/clvrmnky: I don’t think that anyone is presented as post catholic in Star Trek.
@1: Of course, if we’re going to bring up that speech (which I thought of, too, the second I saw the title of the article), we should bring up what Rhys was also talking about – the Scone of Stone, the MacGuffin of the novel.
(spoilers for The Fifth Elephant) While the legends around the Scone claim that it has lasted for fifteen hundred years, the original crumbled after three hundred (dwarf bread, however inedible, is still bread), with one of Rhys’s ancestors getting an ‘accelerated promotion’ when he saw it happen. And yet the dwarves believe it is still The Thing And The Whole of the Thing, and so it is no less real than the ones before it (probably thanks to the nature of belief on the Disc), helping Rhys to wring the truth about recent events from Dee (among other things). Ultimately, you could say that Pratchett is making a counterargument, asking if there aren’t other things aside from the physical bits that make Theseus’s ship what it is.
So what are your thoughts CW?? Lots of interesting questions and nary even a swing at one? Just seems like you forgot to write the third part of the article…
It would be interesting to see how Brandon Sanderson would tackle this in Stormlight Archive with relation to spren
This reminds me of an issue I had with Tad Williams’ Otherland series.
Spoilers for Otherland if you haven’t read it and are planning on reading it:
In Otherland, the big immortality plot was for billionaires to create a life-like computer simulation and then upload an exact copy of themselves into the system, while simultaneously killing their real bodies (the head honcho billionaire was already a brain in a jar anyways). This never made sense to me. Yes, a perfect copy of you would exist in a computer world, but whatever happens to you when you die still happens. You didn’t escape death. That just always bugged me.
I recall a series (2-3 stories) in ~1980s Analog or Asimov about a technique for teleportation that destoyed you and built a perfect replica (perfect enough so that there seemed to be continuous consciousness) at the receiver. Of course, no one would use it, because it required you to be killed. So our heroes developed an offshoot of Buddhism, (Quantum Zen?) that emphasized the illusory nature of continuous consciousness – your mind is being destroyed and recreated at every tick of the clock. So who cares if your body is destroyed, as long as it was created somewhere else.
The upshot was that the universe was soon inhabited with followers of this sect, as no one else was willing to travel.
There is also James Patrick Kelly’s story “Think Like a Dinosaur.” Interstellar teleportation involves making a copy of the original at the destination, leaving the original at the starting point. The aliens who gave humanity the technology, who look like dinosaurs, require the “equation to be balanced,” which means the original must be killed.
For me, the question of human duplicates is continuity of perception and experience of the original. If the pre-copying person experiences death, then the copy is not the same person regardless of whether or not the copy believe they have continuity with the original.
What if instead of a ship, it was a serial killer’s car that he murdered his victims in? A lot of people would be very hesitant about owning or driving such a car but would they feel better if they knew the entire car had been replaced at one point or another? Or to discover that a car they got instead have been made purely of parts from the original murder car?
Seeing the article title and the Darth Vader picture in my feed, I thought it would pose the question of “when more of the original Star Wars trilogy’s implied backstory has been explicitly filmed and/or retconned than originally existed, at what point does Star Wars cease to be Star Wars?”
Call it the Canon of Theseus.
I would be remiss if I didn’t mention The Prestige.
“It took courage… it took courage to climb into that machine every night… not knowing… if I’d be the man in the box… or the prestige.”
@18: “Continuity of perception” is already a demonstrable non-issue — is it continuous when you’re asleep? under anesthesia? in a coma? drunk? Some people exhibit a form of severe inebriation in which they’re able to carry on a conversation, but they’re actually suffering anterograde amnesia — nothing is being written to short-term memory, and afterward they feel disconnected from their actions while drunk. Do we consider any of those circumstances to disprove the common-sense idea of a continuous identity? (No, but we also have a continuous physical body to bolster the opinion.)
Consider the notions of “immortality through my descendants” (the only kind we’ve traditionally had) and “I don’t want to achieve immortality through my works; I want to achieve it by not dying” (Woody Allen). If you’re okay with propagating your opinions-etc. (imperfectly) through biological progeny or cult-followers (survival of memes), you should be more okay with propagating them (perfectly) through a xox. (Extropian jargon from the ’90s that didn’t catch on: a “clone” is a genetic copy, but a “xox” (from “xerox”) also has your mind.)
This debate has been done to death not only re: Trek-style teleportation, but also in extropian circles re: brain uploading and similar conceptual immorbidity technologies. Basically, neither side is able to convince the other — some people are simply squicked by the formulation of “there’s now a successor with the delusion that he’s me” and others are fine with “society still contains a person with exactly my talents, opinions and party anecdotes.”
For me, it’s the not-dying bit. If you upload a copy of me to a computer, that’s fine for people who still want me around but doesn’t help me who’s still stuck in a rotting meatsuit.
The Bene Gesserit are faced by a similar dilemma in the Dune Series. In order to survive, they must change. But if they change, will they still be Bene Gesserit?
In fact we have a similar dilemma whenever we consider changing our own beliefs and attitudes. If I change, will I still be me?
And what about God? Does God learn from his/her experience? If so, then God is fallible. But if not, then what is God but a kind of big rock?
“Life is change …
how it differs
from the rocks ..”
– Grace Slick/Jefferson Airplane
A real-life example: my first PC, back in my university days.
The first upgrade I did was to replace the stock keyboard and mouse. Not long after that I increased the RAM, which ironically meant removing the existing RAM chips to make room for the new, larger-capacity ones. Later I upgraded the CPU, then I got a bigger monitor, and then I did a sorely-needed hard drive upgrade. Not long after that I replaced the stock CDROM drive with a new-fangled DVDROM drive, and eventually I replaced the case and motherboard at the same time because I wanted more expansion slots and drive bays.
At no point during all of this did I never think of it as a different PC – it was just my PC with more RAM, then it was my PC with a bigger monitor, and so on – but eventually I had enough leftover components to rebuild the original PC.
@23 And what about God? Does God learn from his/her experience? If so, then God is fallible. But if not, then what is God but a kind of big rock?
There are several examples in the bible of God learning/changing. After the Great Flood God seemed a bit bummed by most of us drowning and promised never to kill us all with water again and gave us the gift of rainbows to remind us.
I agree life is change! If you could make an exact copy of say a 20 year old, to include the soul if it is there, separate them, then bring them back together say 20 years later and you would have two different people. They would look slightly different, talk slightly different, like and dislike different things based on those 20 years of separate experiences.
@16/CoolBev,
“The upshot was that the Universe was soon inhabited by followers of this sect, as no one else was willing to travel.”
Oh, I love that!
Well, we’re willing to sacrifice ourselves for the sake of our children, why not be willing to sacrifice ourselves to give another version of ourselves a better future?
I’d appreciate it if someone could track down the name of this story.
The problem with the original ship question is that the original parts have worn or broken enough that they needed replacing in the first place. If you then remake the original ship with the original parts, it won’t work like it did when it first started being repaired. The ship is more than the sum of its parts, in other words: it’s the synthesis of all the working parts. If the parts no longer work, it’s not a working ship; it’s just a collection of junk that maybe looks like the original ship if the parts have been reassembled.
I think (@24) the computer question is a better implementation of the original question. (If we replace all the pieces of the original question, is it still the original question? Lol) If the parts were simply upgraded rather than replaced due to wear, then the original computer really can be reassembled and it will still work as it did before, while the upgraded computer also works. At that point I think a computer is no longer the original when the hard drive changes. It can be cloned, but it’s still a copy of what the original drive “knew.”
The Earth is said to be about 4.5 Billion years old, but I’ve always thought that was a bit of an odd thing to say. At just what moment in the 13+ Billion year history of the Universe did the Earth come into existence?
George Lakoff says language and thought are deeply, foundationally metaphorical. And he means that quite literally.
@27/telyi,
You’re right that none of the original components were replaced due to failure or wear, they were replaced simply because I was upgrading them with better / faster / higher-capacity ones. When the original PC was reassembled, it worked as it had done before.
I ended up with two PCs, but I’m still not sure at what point the upgraded PC was no longer the original.
@1/El_Rubino,
I read that when it first came out, and immediately thought of the “Trigger’s broom” scene from Heroes and Villains, an episode of the BBC sitcom Only Fools and Horses:
https://www.youtube.com/watch?v=LAh8HryVaeY
@Val Cashmere
I don’t think I really have many/any answers, and for each different aspect of the problem that I presented, I’d probably have a different rambling response.
I just like asking the questions because if we one day hope to have some of this science fictional tech in the real world, we’re going to have to think about these issues prior to implementation. A problem we have with tech at the moment is engineers thinking about what’s possible without considering the ethics behind what they’re doing – for example: “I’m just an engineer”. We’re seeing racism being built-in to facial recognition algorithms and tools that courts use in sentencing, and the tech behind that is basic machine learning. If we want to start cloning, teleporting, or digitally encoding humans, then we need to start having these conversations now before we end up perpetuating harmful beliefs in the technologies and systems of the future.
And it doesn’t even need to come down to questions like “does a cloned human deserve personhood?” or “does a cloned human have a soul?” it might be something like “who does a cloned human belong to?” I can easily imagine a future where corporations claim ownership over the humans cloned within their labs. Or with a digitally encoded consciousness, do we want to give them personhood, or do they become a piece of software owned by the company who’s server they reside within?
So, yeah, sorry, I don’t have any answers, just more questions. As a general rule, though, I will always lean towards assuming that any cloned, digitally encoded, or partially robotocised human is a full and proper person deserving of personhood and rights.
And also the opening of John Dies At The End. (Warning: some horror and gore.)
@3, “The human body changes all the time, cells die and are replaced…” — Actually, cells in every organ die and get replaced except in the brain (or possibly in the entire nervous system, I forget), which lends credibility to the continuity of experience argument. As for continuity being interrupted (re: @21’s argument), I think things like sleep or anaesthesia only interrupts the subjective experience in terms of the conscious mind, but it doesn’t interrupt the experience of the body as an entity.
I actually think that Brandon Sanderson’s Realmatic Theory goes a long way in terms of answering the question of the Ship of Theseus, that is: a thing is not only what exists in the Physical Realm, it is also what it is perceived to be– a thing is itself as long as it is perceived (both by itself and by others who have had previous experience of it) to be itself. (I AM A STICK!)
A stickier problem comes with the Star Trek teleportation malfunction or double-sleeving as in Altered Carbon, with either of these cases there is one copy that has a continuity of location and perception that the other doesn’t experience, in which case the former can be said to be the original, but I don’t think it would make the “copy” any less valid. I don’t think such a thing as a soul exists except in the brain and the pattern which we call a mind, in which case if a teleport is truly making a perfect copy, then it would be able to copy a soul as well.
Does anybody remember a long ago short film on public television from Canada discussing the transporter moral dilemma? Drawn more mundane looking than high tech with transporters that look more like quiz show isolation booths or refrigerators or maybe coolers in a morgue than Star Trek TOS.
The central character is an every woman drawn more housedress than scientist who operates the transporter. She worries at some length and clever writing that she might actually be killing the original in the inbox however much the person who steps out of the outbox is or at least seems to be the same person. To end the debate and the film she transports herself and so if such it be self imposes a death penalty, then goes home as the same person quite cheerfully.
Rogue Moon from Budrys has an answer I like better in the book than I would facing it in my own life. Such is commonly applied to what might be described as Quantum duplicates as in Drake’s Queen of the Ice Realm.
@16 CoolBev, @26 Keleborn Telperion: That’s the “Reformed Sufi” series by Ray Brown, four stories published in Analog in 1982-83. So far as I know the stories were never reprinted: you’d need to find copies of the original issues. Full details can be found at this scifi.stackexchange question.
28 Keleborn Telperion “The Earth is said to be about 4.5 Billion years old, but I’ve always thought that was a bit of an odd thing to say. At just what moment in the 13+ Billion year history of the Universe did the Earth come into existence?”
Um…4.5 billion years ago. That’s what “4.5 billion years old” means. That’s roughly 8.5 billion years after the universe came into existence.
What is odd about stating the age of something? I’m 47 years old, so the moment I came into existence in the 13+ billion year history of the universe was 47 years ago. That’s how numerical ages work.
I’m remembering a few examples.
First, Riker and the other Riker created by the twinned transporter beam. How do you decide which one is the “original”? BOTH came out of the transporter beam during the away mission, one on the ship and the other bounced back to the planet.
Second, the two John Crichtons on “Farscape” in which they both think they’re the original and the other is the copy, and the crew members traveling with one or the other each begin to think of the one traveling with them as the original. Before they split up, watching the two of them playing rock-paper-scissors endlessly, always tying, was … disturbing.
And finally, the Schwarzenegger flick, “The 6th Day” in which duplication of the consciousness was explored several ways. The clone with the implanted memories is created after the original died, which was more or less accepted by the bad guys until….
SPOILER
The chief bad guy was okay with it, having been through it himself, until the moment his clone awoke early and started taking over while he was still alive (albeit dying). Suddenly, it mattered very much which one of them had his soul. If either did. Although the two Schwarzeneggers seemed to be okay with it in the end.
To be honest, I never quite understood what the filmmakers were trying to say with that movie.
Can’t remember the title but there was a very good and unsettling short story about a world with teleportation booths of limited range (a couple of thousand miles). So you can’t go directly from London to Johannesburg, you get relayed through booths in Cairo and Kampala.
The main character’s an engineer with the teleport company and one day he gets four identical people showing up in his office; turns out there was a mechanical fault just as this man was trying to teleport, and now there’s a London him, a Cairo him, a Kampala him and a Jo’burg him. They discuss this problem – who gets to have the original’s life? – and eventually decide that the fairest thing to do is simply for each of the four to dial a random address, go there and start a new life. I’ll dial, says the engineer, stepping over to his office teleport booth and thinking It’s getting harder and harder to get rid of these people.
Any English contributors remember this? ‘The Giftie’ – a cheerful, cheap-as-chips made-for-tv film starring Richard O’Sullivan. Somebody has uploaded it onto YouTube –
https://www.youtube.com/watch?v=MyDyFaYQ1AQ
The video quality is terrible. The storyline (given the budgetry constraints) is excellent.
@36/PaulB,
See Wikipedia “Sorities Paradox”, and substitute “moment in time” for “grain of sand”.
I see it as loosely related to the Theseus story here. But of course, I was being a bit whimsical. You should probably take anything I say with a grain of salt. Or else a grain of sand.
Let’s get all meta about this.
If you reboot a movie series, changing some elements here and there, and then keep evolving that in the sequels until every part has been swapped for something new, is it still anything to do with that original movie series?
@41/cecrow,
In the case of Star Wars: yes.
In the case of Star Trek: no.
If you reboot a movie series, changing some elements here and there, and then keep evolving that in the sequels until every part has been swapped for something new, is it still anything to do with that original movie series?
Ah, the Paradox of Kurosawa’s Ship.
Red Harvest — Yojimbo — Fistful of Dollars — Last Man Standing
Seven Samurai — The Magnificent Seven — The Three Amigos?
@40/Keleborn Telperion: This reminds me of the day when I tried to introduce the stack datatype to a bunch of people who didn’t have a mathematical or IT background. I had planned to build a stack of paper on my desk, but when I started with the empty stack, they protested. There is no such thing as an empty stack! And one piece of paper isn’t a stack either! Neither are two pieces of paper, or three, or four!
For a mathematician or a computer scientist, empty heaps of sand are no problem at all :)
@42/Keleborn Telperion: The answer is no if you swap out the brain, or the heart.
@43/ajay: There’s a similar phenomenon in linguistics: the dialect chain.
And in biology: the ring species. https://en.wikipedia.org/wiki/Ring_species
@45/ajay: Very cool.
I read a short story once that is a good example, but I just spent an hour unsuccessfully searching for it. Hopefully someone else will remember it and have better luck. I think it is Ray Bradbury. The story consists of a husband trying to convince his wife not to leave him. He argues that a body’s cells are completely replaced after a certain number of years, therefore they are both different people than when they first met. She agrees that they should get to know each other and give their marriage another chance. Sorry for the vagueness.
Is there a transitional state, that is my marker. And there is, even in Star Trek (“Realm of Fear” shows us the transport process from the POV of someone inside the “beam” and there is some degree or form of consciousness all throughout the process so the Theseus Paradox is not triggered), in just about all of these except Darth Vader. Anakin Skywalker is completely replaced by Palpatine’s puppet, the murderous automaton Darth Vader. Darth Vader is the machine where there used to be a person.
@39 Yes, I’m Scottish and I remember that tv play; that was pure nightmare fuel that was. The title is taken from the final stanza of the Robert Burns poem “To A Louse”:
@44/Janajansen,
Like they say, age ain’t nothin’ but a number. And neither is zero.
Wait, I think I confused myself there.
I like Johnny von Neumann’s definition of the number one: the set containing the empty set.
Someday I’m going to have to go into a restaurant and order an empty stack of pancakes. Just one, of course.
@49/Keleborn Telperion: Von Neumann was amazing anyway.
An empty stack of pancakes with an empty heap of maple syrup.
@31 A problem we have with tech at the moment is engineers thinking about what’s possible without considering the ethics behind what they’re doing
This is why I think the human race is doomed. When they first tested the Atomic Bomb the scientist actually took odds on the chances that it would set off a chain reaction that would set the entire atmosphere on fire. If I recall the odds were pretty low but not zero yet they set it off anyway.
@36 What is odd about stating the age of something? I’m 47 years old, so the moment I came into existence
It has been 47 years since your mother gave birth to you but possible not when you came into existence. This is the key argument in the debate between Pro Life/Pro choice but even applies more to the current discussion. When did the ‘world’ become the ‘world’ is as valid a question as when did you become ‘you’? When did a ‘thing’ become that ‘thing’ and is it still that ‘thing’ if it changes?
We humans like set answers, definitions that are always true, yet in my experience there is no real truths as things are ALWAYS changing.
@51/sdzaid,
Re: “When did a thing become that thing and is it still that thing if it changes?”
Oh, Parmenides solved that problem a long, long time ago. There is no thing. So no problem!
Solves the problem of the human race being doomed, too.
“You see Mr. Pilgrim, he has always pushed that button, and he always will push that button” (Slaughterhouse Five, Kurt Vonnegut)
@51 Regarding Earth, 4.5 billion years ago is probably the best guess of when Earth finished coalescing into a planetary body.
@53/Noblehunter,
Re: “Regarding Earth, 4.5 billion years ago is probably the best guess of when Earth finished coalescing into a planetary body.”
1) Yes, exactly – the best guess in a long series of guesses, each one slightly better than the one before, until finally …someone stuck a toothpick in it and it came out clean, perhaps?
2) “… when Earth finished coalescing into a planetary body” … So, it was already Earth while it was finishing coalescing. And when it finally did coalesce, it became Earth ..again? Oh, I get it – just like renewing a subscription!
3) Did Thera collide with Earth? Or did Thera collide with some other planet, and the two together became Earth? Meiosis and Mitosis, I never could keep those two straight.
@3/sdzald, @33/tkThompson: I recall reading a short story where the narrator uses the turnover of the body’s cells to win acquittal on a murder charge…but since he described the mechanism in detail from the witness stand, including his efforts to actively remove some of his old tissues (by, say, bathing), he is promptly arrested for his own murder upon leaving the courtroom. For the life of me I can’t recall the title or author, but I always thought it was a great take on the topic.
@53/noblehunter, @54/Keleborn Telperion: My planetary science is a bit rusty, but IIRC an object is a planet once it either reaches some fraction of its final mass or when the accretion rate drops below some threshold; prior to that, it is proto-<insert name here>. And Earth was Earth both before and after Theia collided with it, since the former was significantly more massive and remained in its same orbit (but now new and improved, with hat satellite!). But that bit about dominating its orbitshould now bring to mind the decade-old question: was Pluto ever a planet? :-)
@54, 55 My planetary science is really non-existent but I would say Earth became “Earth” when it becomes a useful distinction between Earth and proto-Earth.
The teleporter/Prestige “problem” has terrified me ever since read of it in (I think) John Dies at the End. (Which has its own hilarious “Ship of Theseus” style prologue.) Of course the duplicate remembers a continuous series of events; entering the device and then exiting at the other end. But the original goes to his death.
Orson Scott Card wrote a short story in a similar vein, called “Fat Farm”, where a corporation clones fitter, healthier bodies for its gluttonous clients. The twist is that there is no actual transference of consciousness as promised; instead, the New Skinny You is a perfect duplicate who thinks the procedure was a flawless success, while the original (being no longer a legal entity) is sent off into slave labor. (But at least they get the opportunity to burn off all those calories!
@51/sdzald: “When they first tested the Atomic Bomb the scientist actually took odds on the chances that it would set off a chain reaction that would set the entire atmosphere on fire. If I recall the odds were pretty low but not zero yet they set it off anyway.”
Here’s what I found on the subject:
According to 109 East Palace by Jennet Conant, Edward Teller came up with this scenario in 1942. It caused quite an uproar (“This would be the ultimate catastrophe”), and they decided to check Teller’s calculations. Eventually Hans Bethe “reached the ‘reliable conclusion’ that there was a flaw in Teller’s theory, and while nitrogen and hydrogen were unstable, it was highly improbable that an atomic explosion would create the conditions to set them off.” So they proceeded with the atomic bomb. Three years later, on the evening before the test, Fermi “unaccountably announced his intention of taking bets from his fellow scientists ‘on whether or not the bomb would ignite the atmosphere, and if so, whether it would merely destroy New Mexico or destroy the world.’ ” The book doesn’t mention if he actually did take bets, only that his superiors were angry at him for bringing up this old subject again.
@58 Thanks for the details, history always interest me. Even so I think my point still stands. If God/nature doesn’t do us in first, sooner or later some scientist or group of scientist is going to roll the dice once too often and they are going to come up snake eyes. Like Corey mentioned all to often people don’t stop to think about the implication of what they are doing. Many of the Nuke bomb guys AFTER the fact started to doubt the wisdom of what they had done. Great the horses were already out the barn door..
@55/Ian,
That is a very sensible way to define the relationship between Earth, Proto-Earth, and Theia. As for Pluto, it seems to me that the Astronomers are trying a bit to have it both ways by calling it a dwarf planet. Since it plays tag with Neptune (they call it synastry, everyone) one wonders if it might be called a moon. But they seem to insist upon making how the object formed essential to whether it is to be called a planet. If a large asteroid of just the right mass and velocity were to collide with Pluto so that the resulting object found itself in a nice nearly circular orbit (assuming that’s possible), I doubt that they’d be willing to call the result a planet.
In other words, what it “is”, and what we choose to call it, depends on how we want to think about it.
@51/sdzald was, I believe, making a similar point when saying:
” When did a thing become that thing and is it still that thing when it changes?” and
“We humans like set answers, definitions that are always true, yet in my experience there are no real truths as things are ALWAYS changing.”
In order to use language to describe and conceptualize our experience, we parse that experience into nouns and verbs, things and actions, objects and relations, elements and sets … probably the writers of computer programs have their own terms for this. Often we are able to easily distinguish things with no ambiguity. A cell is a cell and not an air bubble, even if the first time I looked into a microscope I had some difficulty distinguishing the two. We get used to the idea that the objects we see and name, and even the ideas that we name, are quite real and have stable existences. Then some situation arises where when we attempt to reason with these words we are left frustrated and disconcerted. What is love, really? What is God? All Cretans are liars; and being Cretan, I should know.
At this point we become aware that our definitions, our “things”, are not simply “out there”; we participate in making them. Like the observer in a quantum mechanical experiment, we insinuate ourselves into the result. That is not to say that there is no reality, just that sometimes language has difficulty grasping it.
Parmenides and Heraclitus were a couple ancient Greek philosophers during an era when the Greeks were beginning to sense the power of logic – Thales, who got mathematics on a deductive basis, was more or less contemporaneous. Parmenides argued that the idea of change was incoherent; one thing could not change into another, in fact one thing could not be separate from another; there was only one thing, the One. Parmenides wasn’t just being an irritant, he could see as well as anyone else that didn’t match our experience. But if you believe in logic, that is the inevitable conclusion you must reach. Heraclitus took the opposite view: change is the only thing that exists. Rather difficult to express without calling upon the notion of a thing, as in changing from one thing to another, which is why he tried to communicate it through images like ” You cannot step into the same river twice.”
It is as if Parmenides wanted to reduce language to just nouns – in fact, just one noun- whereas Heraclitus wanted to reduce language to just verbs, in fact just one verb.
A near contemporary of theirs in China, Lao Tzu, did a little better:
“The Tao that can be told
is not the eternal Tao”.
More than 2000 years later, Kurt Gödel would say the same thing.
@60: According to the current IAU definition, a key distinction between ‘dwarf planet’ and ‘planet’ is that the latter has sufficient mass to dominate its orbit. So, if an object collided with Pluto-Charon and the result bumped its mass over that limit, it would have to be reclassified as a planet…unless they decided to change the definition again to keep it out of the club. Much of the controversy—apart from people who wanted to save Pluto’s status on the basis of nostalgia—is that ‘sufficient mass’ and ‘dominate’ are somewhat ill-defined…
Most people think of concepts as clearly defined and discrete, but that just isn’t true. Some philosophers tried to invent a perfect language with non-fuzzy concepts, but those aren’t practical for everyday communication. One problem with teaching computers to understand natural language is how to teach them to deal with fuzzy concepts. For humans it is obvious that a big mouse is smaller than a small elephant, but it isn’t easy to teach a computer to handle such words. Computers want exact numbers (<x cm is small, >y cm is big). Prototype theory is an attempt to work with degrees of membership in a category (a sparrow is a more prototypical bird than a penguin).
@61 I wonder if Planet 9 (I haven’t heard if the math has been retracted) will pose a problem to current taxonomy of planets. It’s supposed to be big enough to be planet-sized but given how long its orbit is, I wouldn’t be surprised if it had trouble “dominating” its orbit.
The problem with a lot of the “recreating the original out of discarded parts” examples is, as has been pointed out, that the parts are usually discarded because they are junk.
In the original, specifically ship, thought experiment, this is not the case. Theseus’ ship is hand-crafted, not machined, so each piece has to be adjusted to fit. When Theseus discards part of his ship, it’s easier to discard a whole section, not just the broken part. When the second ship needs repair, the resources to replace a whole section aren’t there (Theseus has already used them up) but there is a whole section that that Theseus has left behind that can be repaired (with a lot more effort than just replacing the section). Over time, all the parts of the second ship will have been part of Theseus’ ship. All the parts of the second ship weren’t part of Theseus’ ship when it was built, but (because the replaced sections can overlap), all of the second ship could, at least in the thought experiment, have once been part of Theseus’ ship (just not concurrently), and the second ship will not be built from junk.
I mean, the second ship won’t look exactly the same. They’ll look reasonably similar (same size, same design, so have the same basic shape), but all the hand-hewn interlocking planks will fit together differently, so the pattern on the hull will be different. But by the same token, both hulls will have a completely different pattern from the hull of Theseus’ ship when it was launched. And the second ship is still the only one with any parts from Theseus’ ship when it was launched.
Here’s my take on this: both are fully functional ships, and therefore can be treated as such. The ship Theseus owns, however, is the one that is perceived to be the original by everyone. Therefore it’s the original.
That seems to be the way the Federation decide to go, as well in the Will/Tom Riker transporter accident. Until the accident, they were the same person. After the accident, the individual that chose to become Tom was trapped with no outside contact, while his counterpart continued with his career. The Federation seemed to decide that the latter was the original, and therefore got to keep the Will Riker unique identifiers, purely because he’d been the one the Federation had been interacting with.
Next thing: yes, as the Cold War intensifies, and MAD looked disturbingly possible, the scientists involved in creating the atom bomb regretted letting the genie out of the bottle. But…
“We ain’t ded.”
And consider this: we now live in an age where people aren’t just asking about the morality of certain research, but the people being asked to do the research grew up on and were inspired to become scientists by fiction that asked these questions. They’re the ones asking the politicians for ethical frameworks to guide them. They are also the ones that deliberately create a psychotic AI called Norman to demonstrate the dangers and limits of self-learning before we create self-aware AI. (Some of Norman’s responses to Roshach Tests are disturbingly specific, especially the “… into a dough-making machine.” Reponse).
So I’m not too worried about Science Unleashed going horribly wrong, just as long as we have a healthy sci-fi genre exploring these questions.
Hopefully someone can answer this question:
In Marvel Comics, the Vision was made out of spare parts for the original Human Torch (Jim Hammond, I think). So how come they don’t look alike, and have completely different powers?!
Great essay!
@35/DavidGoldfarb,
David, I want to thank you for not only tracking this down, but also providing the link to the SciFi.stackexchange question site. That, apparently, is the way one goes about tracking down things like this in general.
It’s a bit frustrating that even Amazon has only one of the relevant issues. It looks like there may be a possibility of getting them as Kindle downloads, although that may only apply to current issues of Analog.
@64,
A comparable story (it may even be true) to the Ship of Theseus is one about the highest-time DC-3. When some people started going through its maintenance logs, they found that there were four pieces that had not been replaced since the airplane had left the factory, and these were bolts in one of the engine mounts; everything else had been replaced.
Certainly, some of the parts from that DC-3 could have been re-used: engines and propellers are routinely removed and replaced, with the removed engines and propellers going of to be repaired or refurbished, and spare engines and props being installed in the original plane, and the removed engines and props being reused elsewhere. Other parts couldn’t be reused.
As a relevant aside, well into the 20th Century, ships were largely hand-built items, not built of interchangeable parts, especially their hulls. Even so, they could replace a single plank, not an entire section. On the other hand, owners were frequently very unsentimental about their ships: repairs could easily exceed replacement price, so a wooden ship would be stripped of anything valuable and then burned to recover the metal parts. They used to do that with houses and barns, too.
Trying to drag my comments into something relevant to the original essay….
While the Ship of Theseus “problem” is usually applied to inanimate objects, such as My Grandfather’s Hammer (“it’s had the handle replaced six times, and the head twice…”) humans replace nearly all the cells in their body, repeatedly, throughout life as the cells wear out and die. See https://www.livescience.com/33179-does-human-body-replace-cells-seven-years.html
——————————
As a nearly completely irrelevant aside, DC-3s operated in revenue service into the 1990s or so, some serving as such over 50 years from their first flight, with 80,000+ flight hours. The usage has been beaten by modern aircraft, with the high-time 747 having well over 100,000 flight hours.
@69/Swampyyankee,
Nice story about the DC-3. Somewhat inexplicably, it got me to thinking: isn’t every idea in our heads somewhat like this?
Possibly not the best example, but the immediate thought I had was of how my ideas of God have changed since I was a child to now being nearly 60 (and by the way, part of me finds that hard to believe: surely I am still the beautiful young man with the agile mind that I was at 19!) When I was a child my concept of God was that of a kindly old man like Santa Claus; when I got a bit older it was that of a judgemental and interfering busybody; a bit older and I decided he was a projection of man’s hopes and fears and did not exist; a bit older yet again and I decided that man was incapable of comprehending God and therefore the concept was meaningless; to now feeling like I wish there were a God, and that there just might be, only not the one that has been described in the Bible.
Like Barack Obama saying that his ideas about gay marriage had “evolved”, aren’t all of our ideas constantly evolving – indeed, much more continuously, and with less conscious notice, than my example of my own ideas of God? Perhaps more significant are the slowly evolving ideas of who we ourselves are, who other people are, what it means to be human and what it could mean to be human.
” She said
I know what it means to be dead
I said
Who put all these thoughts in your head?
And she’s making me feel like
I’ve never been born”
– She said/ Beatles
@@.-@
Actually, the Constellation built in the 19th Century was a fraud: Congress would not authorize new construction so the 1797 ship was “repaired” into a ship with a different length, different beam, different hull form, and possibly different internal arrangement.
@69 – now you mention it, I remember debates (not about the D.C.-3, but other plans) as to whether vintage planes “still flying” are original or replicas once all the parts are replaced. Specifically, whether replacement parts made using the original techniques are okay, but 3-D printed parts are somehow “cheating”, and therefore make the aircraft a replica. I just wish I could remember whether is was IRL or on-line, never mind where I heard/saw it <sigh>.
Also, I see why you’re querying the ship-building, but I didn’t say it was impossible to replace individual planks, just easier to replace a section. You seem to be comparing 20th Century ship building techniques to Bronze Age. I might be wrong, but I’m going to suggest that the shipwrights you refer to used milled wood and mass-produced steel tools. Even then, the planks don’t fit together well, so often a fair amount of corking is required to stop the hull leaking. Hence why the ships were considered disposable (and fire wouldn’t burn hot enough to damage the metal fittings, whereas trying to physically remove them likely would).
Compare that to the Mythical Theseus and company. They didn’t use nails (or other metal fittings), and constructed their ships on beaches, using tools they’d likely made themselves. They were aware of cork (it’s use as a bottle-stopper goes back to Ancient Egypt, and it’s a Mediterranean tree), but there’s little evidence of it being used in ship’s hulls until Roman times, so each plank was made a bit more bespoke than modern sensibilities would suggest. It’s this type of ship-building that Plutarch (the creator of the thought experiment) had in mind when he came up with it (about 70 odd years after the birth of Christ).
@71 – ah, but that raises an interesting wrinkle. If an object or person has never been linked to the original, but is swapped out and everyone behaves as though it’s the original, does it become the thing for all intents and purposes?
I’m thinking Ray in Due South, or the weird theory that Paul McCartney got replaced by another Paul McCartney back before the Abby Road record when the “original” died in a car accident….
@72, I think you mean caulking, not corking. It is impossible to make a wooden ship watertight, as the size of the planks vary with their moisture. Caulkers — it used to be a skilled trade — would pound oakum between the planks and seal them in with pitch.
They were aware of cork (it’s use as a bottle-stopper goes back to Ancient Egypt, and it’s a Mediterranean tree), but there’s little evidence of it being used in ship’s hulls until Roman times
I’m not aware of any evidence of cork ever being used in ships’ hulls.
As swampyankee says, I think you mean caulk. Oakum (fibres of unpicked rope) and pitch, to plug the inevitable gaps between the strakes – “ Make thee an ark of gopher wood; rooms shalt thou make in the ark, and shalt pitch it within and without with pitch”, God tells Noah, and the Romans and Egyptians certainly used pitch though I’m not sure if they used oakum; at least one find, a Roman shipwreck in the Thames, has caulk made up of wood shavings and pine resin. (No pitch to be had in Britain.)
@75/Ajay,
Wikipedia, Scots Pine, used to make rosin. Is that not pitch?
Pitch is a pretty generic term that could be defined as “really thick tar”. There are substances called “pitch” derived from plant resins (pine trees do, indeed, produce rosin) and from petroleum. Ships, I believe, were sealed with pine-derived pitch.
Getting hung up on precise shipbuilding techniques is kind of missing the point, especially as Plutarch mean the story to stand for a general philosophical problem, not to something which only applied to, say, pre-Roman ships. (The story, remember, is about a pre-Classical ship which supposedly survived, in its continually repaired form, down to at least around 300 BC, according to a writer who lived in the late 1st/early 2nd Century AD.)
The bit about building a second ship from discarded pieces of the first isn’t part of Plutarch’s discussion, which only dealt with the gradual, piece-by-piece repair of a single ship. It’s a really interesting extension of the problem, of course, but not one that can be fruitfully addressed by appeals to “how the historical[?] Theseus would have repaired his ship”.
In terms of the original story, the more directly relevant American case, by the way, is clearly the USS Constitution, which has been periodically refurbished and repaired (most recently in 2015-2017), but is still generally considered “the same ship”, including in the sense of “the same commissioned ship in the United States Navy”. (HMS Victory, currently undergoing restoration work, is the obvious British example.)
At the risk of heading further down the technical aspects of ship-building…
this is not the first time I’ve got cork and Caulk mixed up. Full disclosure: I’ve had no formal training, and what I do know is from helping my Dad (who was a ship-wright) repair wooden boats (some over a century old, bringing in the “ship of Theseus” argument) as a disinterested child. In my defence, I’ve seen him use cork as caulk (no idea how wide a practice it is, though), though he usually prefers something he calls “Black Mastic”. I’ve probably got the spelling wrong, as I’m naming it phonetically from memory. <sigh>
also “water-tight” and “all the leaks are plugged” do not equate to “no water in the hull”. No matter what the material, I’ve never heard of a ship or boat that didn’t have water sloshing around the inside of the bottom of the boat (known as bilge water, if you ever wondered pirates were going on about). As pointed out, the natural flex of a boat will draw water in between the planks and through cracks in the wood. It’ll also be a combination of osmosis, leaks from engines, water splashed down hatches (either from rain or waves over the decks), sweat from the crew, and condensation that forms on the hull where damp air contacts a surface cooled by the water on the other side.
And yes, any wooden boat (or ship) that’s been in dry dock for any length of time will leak like a sieve once it’s refloated until the wood absorbs sufficient water and expands. I’m glad I live in an age of electric pumps, how much water I’ve pumps out over the years. Fun fact: you have to deliberately craft your wood to take the expansion into account, otherwise the hull can distort alarmingly once it hits the water. It’s as much art as science, apparently.
This all detracts from my main point: the mythical second ship could still, in theory, be a sea-worthy vessel (for the Mediterranean). It seems (at least to me) a fundamentally flawed argument to use the example of 20th ships (built to last a season or two with mass-produced parts and tools) as an example of how a Bronze Age mythical ship (built to last decades using hand-made parts and tools) would be maintained. That’s even before we get to the part where the whole thing a thought experiment based on a Roman philosopher’s understanding of how that mythical ship was maintained a few centuries before he was born.
@78 – so Plutarch didn’t come up with the “second ship” part of the thought experiment? Huh.
Do you know who did? And when? Not that it matters, just interested in how long it took for someone to come up with that.
oh, and Kudos for coming up with the HMS Victory example. :).
@@@@@3 ahhh you beat me to it! But yup! As a biochemist I can say this is true. We actually replace all our cells (arguably not the ones in our brain though that is now debatable as we have learned the brain keeps growing – we used to think it didn’t) every three years I think. Modern Buddhism uses this fact in a lot of interesting ways (BAD modern Buddhism acts like it is scientific when it tries to do so). I have seen this question asked before but never knew it came from Greek Philosophy – I should have guessed though as Greece practically asked every question worth asking.
Other examples: From video games Soma (which I highly highly recommend can’t say more as would be major spoilers) Alpha Centauri a great strategy video game has some great things that deal with it also.
For TV – there was a twilight zone episode that I now wonder if it was based off some of the short stories people mentioned. An alien race came to give us transporter technology and everything was fine until we figured out that it was killing the original and recreating them far away on another planet. I always thought star trek took care of this problem by hand wavingly saying (as only Star Trek can do) that its transporter actually sent the original particles to the new location and reassembled them.
Off topic – I don’t see the issues with the Gang crime identifying software the OP seems to see. Though the fact the people who have problems with it are asking if they are making software to help people predict police raids and can’t say we should be making software to help the police – pretty much means I discount everything they say. If you are not on the side of the police over criminal gangs – then you are insane.
@@@@@ 25 – don’t tell that to a fundamentalist while I agree with you a fundamentalist would want to string you up. @@@@@60 – thank you for catching the fact it doesn’t mean reality doesn’t exist – to many people take the correct things you said to mean that. Your interpretation is the correct one.
If a tree falls in the forest and no one is around to hear it – the differences in air pressure we would perceive as sound if we were their still exist.
@81/dwcole,
Thank you!
By the way, it is not really possible for a tree in a forest to fall to the ground. For you see, to reach the ground, first it must fall halfway toward the ground. Then from there it must fall halfway toward the remaining distance … and so on and so on infinitum, finally forever hovering above the surface like what we observe when an object falls into a black hole.
Some of those Greeks were not only pretty smart; they also had a rather finely developed sense of humor.
(Zeno’s Paradoxes, adapted.)
@dwcole #81: that figure of “cells are replaced every three years” is an exaggeration and oversimplification at best. Cells in the digestive epithelium are replaced on a less-than-daily basis, IIRC. An osteoclast would normally divide enormously less often, or never. The figure I’ve heard for fat cells is about 7 years.
@80:
Do you know who did?
I’ve only done some cursory searches, but it appears that the idea goes back to Thomas Hobbes’ De Corpore (1655):
This page has an interesting variation which seems to force you towards concluding the assembled-from-original-pieces ship is is the “original” ship:
Objects have no consciousness, and their value is what humans assign to it. So, the ship Theseus continues to use, or the family axe the family continues to hand down through generations, those are “the original” object.
When it comes to people, well, that’s something else entirely, I have no answer there.
The question of when we can start talking of a thing as the thing is relevant for a person (@51), but not really for the Earth. When we say that the world was formed 4.5 billion years ago, we don’t mean 4,500,000,000 years to the second. Only that we had something that looked like a planet 4.5 billion years ago, and not 5 billion years ago.
But watching the Doctor Who episode Heaven Sent, I was faced with a strange question.
(spoiler).
At the beginning of every loop, the castle is reset to the exact same shape (apart from a few things, but it wouldn’t be a Stephen Moffat episode without some plot holes), including the Doctor, who is recreated with the exact same memories. As a consequence, he acts exactly in the same way every time, more than a trillion times. Every time, he goes to the same rooftop and sees the stars, and from their position, he deduces by how much he has “travelled into the future”: “If I didn’t know any better, I’d say we travelled two thousand years / twelve thousand years / six-hundred thousand years / twelve hundred thousand years / two million years / twenty-million years / fifty-two million years / nearly a billion years / well over a billion years / two billion years into the future”. From one loop to the next, he sees exactly the same night sky, as the stars can’t have moved much in less than a week. Yet there must have been a first time he said “a billion years into the future”, seeing a sky that was exactly that one that prompted him to say “nearly a billion years into the future”.
So this made me think: for as long as we have known about dinosaurs for instance, they went extinct 65 million years ago. In what year will we start using a different number?
@85/MaGnUs: Yes. And humans assign different values to different kinds of objects. Therefore:
@84/PeterErwin: The ship in the original article is an object of daily use. Replacing parts of an object of daily use is a normal activity and doesn’t change the object’s identity. The ship in the museum, on the other hand, is a historical artifact. Rules are different for historical artifacts. As soon as the thieves replace the first piece, the ship becomes part historical artifact, part forgery.
I think you’re missing the point about Anakin, Corey. It’s not what has been replaced that makes him ‘more machine than man’ to Obi-wan, but Anakin’s actions. Not aiding Mace, killing the younglings, serving Palpitine/Sidious, and later hunting down the Jedi are all, to Obi-wan, acts of a death machine, not the good man Anakin Skywalker was. For Obi-wan, is prosthetic limbs and life support system reflect that transformation rather than being an integral part of it.
And another thing: as we see, Sidious’s intention to lure Luke to the Dark Side indicates that the Emperor believes Luke has begun to walk the road his father did. Luke’s prosthetic is, again, a symbol of his potential transformation, the difference being he makes a different choice. It’s possible it also allows him to see there may be good left in Vader, too, but that’s not made either in the film or the novelization, so that’s only speculation on my part.
If you want another application of the Ship of Theseus, listen to the first episode of Season Two of Malcolm Gladwell’s Revisionist History.
“When is a golf course still a golf course?”
http://revisionisthistory.com/episodes/11-a-good-walk-spoiled
The Ship of Theseus, as applied to human beings, was one of the main themes of most of Jack Chalker’s books. Which is both what I liked about him–it raises fascinating questions–and what I disliked–try writing something new, dude! :)
Most of his books involve either people being put into new and completely different bodies, or having their minds altered somehow. Which, between the two, covers just about everything. His stuff’s a bit dated these days, but might be worth checking out if you find the questions interesting.
I think that a useful approach to this problem is to discard entirely the idea of a static “thing” and consider, instead, a “thing” as a set of processes, relatively stable/consistent over time. With this caveat “sameness” becomes a relative, rather than an absolute, concept.
The ship is relatively consistent over time (“the same ship”) because only a few of its constituent processes (e.g., the planks) are replaced over time. The planks and other parts, as they are removed and stored for the original reconstruction, are each “the same” for the same reasons – relatively consistent because, as time goes by, molecules and such enter and leave the larger process of “the plank.”
When some fine Daedalus takes those planks and rebuilds “the ship,” it is not “the same,” because it is not consistent over time with respect to the original ship.
This does not answer the question of “which is the Ship of Theseus.” The answer to that is, whichever ship Theseus looks at and says, “That’s my ship.” (And Theseus can have more than one ship at a time…)
Applying this to the Darth Vader scenario, or the Altered Carbon scenario, is not as easy, because we haven’t defined what the relatively-stable-over-time processes of a “person” are. Do they include the body, as a whole or in parts? The mind? All of it or only the memories? Without answers to these, and many other, questions, we are incapable of answering those scenarios.
Answering these questions would allow us to do all sorts of things, like determine more accurately than Turing’s much-abused test can do, whether an AI is a “person,” or an alien life-form. They might even get us somewhere nearer to the elusive concept of the “soul.”
JanaJansen @87
The ship in the original article is an object of daily use…. The ship in the museum, on the other hand, is a historical artifact.
For what it’s worth, the ship in Plutarch’s example was itself a “historical artifact”. (It had indeed once been an object of everyday use, but that’s true of most historical artifacts.)
That’s why I noted the similarity to the USS Constitution and HMS Victory: former objects (ships) of daily use become historical artifacts.
@17 There was a great episode of The Outer Limits made of this story.
Also, I seem to recall that this was the reason McCoy didn’t like the teleporter in Star Trek TOS.
Lastly, there is a great argument about this in Peter Clines’ “The Fold”
The doctors are avoiding me.
My vision is confused.
I listen to my earphones,
And I catch the evening news.
A murderer’s been killed,
And he donates his sight to science.
I’m locked into a private ward.
I realise that I must be
Looking through Gary Gilmore’s eyes.
Looking through Gary Gilmore’s eyes.
The Tin Woodsman in the books was created by the Wicked Witch of the West replacing him piece by piece.
@93 I thought McCoy’s problem with transporters was not based on any philosophical worry about the continuity of the soul through transport, but the more concrete concern that he just did not trust the machinery to put all the pieces back in their proper place afterwards?
This is a classic problem in science-fiction. In addition to the Will/Tom Riker from TNG, there’s an original series novel Spock Must Die! where the question of whether the person coming out of the other end of the transporter has an immortal soul triggers the rest of the story.
The Prestige has identity at its core, addressed from multiple viewpoints – the main characters end up with several different answers, depending on how you count it. (SPOILERS: am I the same person after a tragic event? will I be the one in the tank or on the stage? do we have one life, two or something else?)
Altered Carbon has a scene in the book where the main character must decide which continuity he wishes to preserve, hence who he will be afterwards. The third book then has another twist on the “which is me and who am I” question, where one person is at the point where they have not yet had the same life-altering experiences, but also have not made all the same mistakes yet. Another character owes a debt to our protagonist, and gets to choose which version he will pay. And so on.
And of course, there’s All You Zombies …
Howard Taylor (Schlock Mercenary) addressed some version of the question years ago, in the creation of 950,000,000 Gavs.
https://www.schlockmercenary.com/2002-07-14
What’s really amusing is that the answer to the questions of “what makes you you?” isn’t actually difficult to answer; rather, most people just don’t like the answer anymore. :)
@23: The original lyric sheet credits that to Paul Kantner, not Grace Slick — but doesn’t acknowledge that it’s a slightly edited version of lines from John Wyndham’s The Chrysalids (Rebirth in the US). Kantner may have been the first serious SF reader (i.e., reading something beyond Stranger in a Strange Land) to become a major rock musician; his Blows Against the Empire (a few years after those lyrics) was the first rock music nominated for a Hugo.
@Connie Williamson: We’re seeing racism being built-in to facial recognition algorithms and tools that courts use in sentencing, and the tech behind that is basic machine learning. From bad data, which is the sticking point with any “machine learning”. (For an extreme/deliberately-broken example, see MIT’s “Norman”, mentioned in @65.)
@100,
I used Grace Slick to help cue people’s memory, in case they had heard the song. Her voice is rather memorable.
@96/random22: I think McCoy’s problem with transporters is just part of his general distrust of machines. As you say, it certainly doesn’t have anything to do with transfer of souls or making copies of people. I found three examples – in “Obsession”, he complains about “spreading a man’s molecules all over the universe”, in TMP, he sends the others first because he first wants to see “how it scrambled [their] molecules”, and in “Encounter at Farpoint”, he travels by shuttlecraft and asks Data: “Have you got some reason you want my atoms scattered all over space?” It seems that his dislike of transporters gets worse over the years.
@61/Ian,
So Ian, if we replace a very large “planet killer” asteroid that is headed right for us with about a billion tiny asteroids of sum total equal mass headed right for us, is it the same asteroid?
“A difference which makes no difference is no difference.” – Korzybyski
I’m inclined to say Kinetic Energy is Kinetic Energy, but I suppose depending on the mass it might be better to fry the atmosphere a bit than to have a huge tsunami.
The scenario is being posed at @34 on the “Space Dads for America: Armageddon” thread, and I imagine readers on this thread might be interested too.
@103/Keleborn Telperion: Yes, indeed. And a swarm of asteroids might in some ways be worse, since while some of the smaller pieces might burn up in the atmosphere, those large enough to reach the ground would likely spread over a wider area than would have been hit by the original object (although tsunamis, fires, and dust-induced weather disruptions would probably still be a problem). Perhaps it might help if we could pulverize it into pieces all smaller than, say, a meter, but if we had that kind of energy at our disposal we could probably use that to alter its orbit to miss us altogether.
@17 Think Like a Dinosaur” was originally published in the June 1995 issue of Asimov’s Science Fiction
And is a SUPERB, award-winning story. Terrific thread.
It’s the gotcha at the end of Veteran by Gavin G. Smith.
This is the link to the OUTER LIMITS version of Kelly’s …DINOSAUR
https://en.wikipedia.org/wiki/Think_Like_a_Dinosaur_(The_Outer_Limits)
Again, one of the best threads on Tor.com this year, easily.
84/PeterErwin – thank you. 1655 seems much later than I’d have thought. It seems (admittedly in 21st hindsight, and having lived with the concept so long I can’t remember where I first learnt about it) such an obvious extension of the original idea.
I’ve been racking my brains trying to remember where I read this, but I recall a short story I read on-line within the past few years. The basic premise is that there is a series of way stations for an alien transporter technology, due to the range limitations of said technology. You walk in one end of a tunnel, and to observers you disappear, but you perceive yourself walking out the other end at the next way station. Until one way station where no one disappears when they use the device. This being a one-way system, they can’t go back to report it’s broken or tell them to stop sending people through.
<spoilers for a story you might never read because I can’t link to it>
at the end, the protagonist realises it isn’t a Star Trek style transporter, but one more like the Prestige, and the only bit that’s broken is the disintegrator that stops multiple versions of you running around the universe. Some people have used it multiple times, so at the next way point there’s several copies of themselves, and each after the first arriving thinking they are the original and “this time it’s worked”!
the story never visits this next way station, but it raises the question of how they deal with the duplicates. Are they treated as individuals, or biological matter to be disposed of as an unfortunate result of a mechanical failure?
In the Cuckoo Saga, the transporter system doesn’t destroy the original, so the main characters have copies on Earth, the ship near Cuckoo, and on Cuckoo proper. The copies can be edited, so that they have somewhat different phenotypes, for example the copies sent to Cuckoo, which has a very low surface gravity, have been made taller and thinner and probably have internal modifications to prevent medical problems from the low gravity. Here, it’s not the original that gets destroyed, it’s the copies, which are, in essence, abandoned and no longer have any contact with the original.
In the Cuckoo saga, how do the different copies perceive themselves? I guess each phenotype has their own communities. How do they perceive the different copies?
@11,
It has been a long time since I’ve read the books, so I am a bit vague about this.
I think each knew they were the copy, because they’ve been sent to a different location. I vaguely remember they also felt expendable, as they were sent on one way trips from which they would not return.
And seen on the tweetbox as I’ve perused these comments…
https://twitter.com/kierongillen/status/1006517126910312448
‘The best Star Wars movie would have to involve deploying intensive cloning techniques in an attempt to rebuild the Alderaan royal family. The greatest stories always have multiple Leias.’
@112/ swampyankee – thank you. Interesting. Do the stories deal much with how they feel being expendable?
@113/Joe – Dawkins’s Beard, that was truely a groan-worthy pun! Well worth quoting! :).
For another real world example look at Bravo November, “Theseus’ Chinook”… a helicopter in service since 1982 with almost all its parts replaced (and its own Wikipedia page!)
@114, It has been a very long time since I read the Cuckoo Saga, so I can’t recall if it was significant.
@117/Swampyankee – fair enough. Thanks for replying.
I scrolled and scrolled but did no one mention Doctor Who and in particular https://en.m.wikipedia.org/wiki/Deep_Breath_(Doctor_Who) where the confrontation with the Half Face Man is exactly this discussion ? It is the Doctor’s own description: he’s replaced in each incarnation but still considers himself an indivdual.
If you enjoy all these quandaries of identity then you must have this in your library. It is a collection of essays with beautiful mind warping thought experiments.
The Mind’s I
by Daniel Dennett, Douglas Hofstadter, and Stanisław Lem
@119/mariesdaughter – fair point, someone should have mentioned it before now! :
A brand new one, “The Singularity Trap” by Dennis E. Taylor, is directly about exactly this issue. As a body is replaced, is it still you? Even if you feel like you are still you, with a new brain is it still you? Can you ever be you again, even if you had normal human body components again? Do you still have a soul or are you just a program emulating the real you?
He also wrote the exceptional trilogy “We are Legion We are Bob” which also touches heavily on the same philosophical concept, but in a different base format. I highly recommend both.