The Ship of Theseus—What is an object?

i want to talk about the nature of objects we've talked some about personal identity what it is to be me but i want to talk about the nature of objects what it is to be this mask for example or this pair of glasses or this key and so forth so we're going to be discussing questions about the identity of objects in general now you might expect that hume's view of objects in general is going to tie in with his view of the identity of people after all we're a kind of object you might think and so it won't be a surprise it does okay now in a lot of philosophers there would be quite a difference in lock for example the continuity of a physical object is different from the continuity of a mere lump of matter that's different from the continuity of a machine or an animal and that's different from what it is to be the same person but in hume as we'll see it doesn't really matter whether we're talking about selves people or whether we're talking about ships or keys or anything else really he gives a unified theory of identity or you might say of well the opposite of identity of diversity of all these objects there really is no identity these objects except something we impose but there is no underlying unity to the thing it's not really one thing we act as if it's one thing we call it one thing because it's convenient for us so let's take a look at hume's view of the nature of objects it's the same as the view of the of the self really it's a bundle theory he attacks the idea of substance and we'll talk about that attack mounted by hume and bishop barkley later hume thinks that all objects are bundles of qualities and we do the bundling or at least it gets done in some way by human nature it's not always conscious though sometimes it's conscious the way we put together objects and form them into unities or at least we treat them as unities but they aren't really just as the self is something more like a theater in which a lot of things are taking place or a commonwealth that really has a kind of artificial unity to it there is no one thing there so similarly it's the case for us and it's the case for every other object let's go back to a pre-socratic philosopher heraclitus famously said you can't step in the same river twice what he meant is by the time you've put your foot back into the river well your foot has changed the river has changed and so really nothing can be repeated everything is changing constantly the only constant heraclitus says is change i think hume has a similar perspective so let's take a look at an object an object like this river the keister the keister is a river in the middle of what is now turkey in the ancient world it was called lydia and it has a kind of unity but imagine going to the kaister and putting your toe in and then putting it in again well is it the same river it's different water notice that's flowing by and you might say yes but it's water in the same banks well not exactly right i mean riverbeds change as the water flows through them some of the dirt get gets washed away the banks slightly change i mean it's very small you're not going to see it in a big way unless there's a major flood going on or some huge storm that changes the path of the river but it is changing very slowly and over time you can see that rivers paths change oxbow leaks form you can find things being you know worn away like the grand canyon and so in short it's not really remaining constant even the river path or bed let alone the water that's going by it well let's take a look at this river somewhat closer to where i am this is the colorado river in austin if we think about that river and think about dipping our toes into it twice we can say yes the water is different now the path um even the riverbed and so on that's slightly different as you can see a lot of things have been constructed of the bag so it won't always be the activity of the water that's changing this it may be other kinds of activity maybe my dipping my toe in actually moves a bit of dirt into the river or out of it and so all of those things can change the path of the river quine talks about this kind of example and he says look you can't stay step into the same river stage twice imagine a river being put together from all these temporal stages here is the keister at this moment the kyster at this moment the kaiser at this moment or the colorado at this moment this moment this moment and so on call those river stages temporal stages of the river you can't step into the same river stage twice because it's gone it was there for only a moment but you can surely step into the same river twice you can say hey i went boating in the colorado a while ago and then i went again later and you're in the same river twice that makes sense but how is that possible well quine isn't just saying that heraclitus is wrong he's saying really technically what we call a river is just a combination of these river stages we apply a term like kaister or colorado to a variety of these river stages but we call it the same river why because the stages are similar so in a certain sense really all we have are the river stages the snapshots of a river that go by think of a film strip where you've got the film of the river and there is there by you know image by image it's just that they go by very very rapidly so that we don't distinguish we group them together and call that one river because those stages are so similar to one another but there is no real underlying unity might you might say there is different water at every single stage and so i go and i look and say ah there's the colorado again well the water i'm looking at is completely different from the last time i was there looking at it still we group them together because they're rather similar impressions we have similar experiences so we call it the same river because the river stages have a lot of similarity to one another it's the same with all objects and so experience presents us with these impressions the impressions are momentary they're of river stages or person stages or glasses stages or water stages or whatever it is and they are in many cases similar enough that we group them together and call them one object so i look over at the door i look over again i say i'm seeing the same door i've got two visual impressions of a door they're similar enough that i call that the same door and act as if the object is continuing but really i'm just grouping together a series of similar impressions at different times so here is how hume puts it the objects which are variable or interrupted and yet are supposed to continue the same are such only as to constitute a succession of parts they're connected together by resemblance contiguity or causation all objects to which we ascribe identity without observing their invariableness and uninterruptedness are such as consist of a succession of related objects we have a variety of different impressions of the door or of the river we group them together and call them impressions of one object and so similarly the river itself the door itself are a series of river stages or door stages we group those together and call those one river or one door but actually what we're doing is bundling together a bunch of impressions into an impression of an object or an idea of an object we're taking those various stages of an object and treating them as if they are a continuing object we're doing it not completely arbitrarily it's not like as if i pick up the paper and i say look it's the same door there's no continuity there they're not very similar impressions at all so there's a pattern how i do this the mind has certain customs and habits for doing it it's not arbitrary but it's also not rationally justified there is no actual unity there i'm doing the grouping and so there is a succession of related objects related stages that are being lumped together and treated as one object but all of that unification is happening in my mind it's not there in the world so think about an object like the ship of theseus this is a famous example in philosophy it began to be discussed among the ancient philosophers certainly by the time of aristotle plutarch writes about it and so let's take a look at this case it's an especially interesting case but quine or hume would say or heraclitus for that better would say look this is the case with all objects not just ships like the ship of theseus theseus and the youth of athens returned from crete had 30 oars and was preserved by the athenians they took away the old planks as they decayed putting in new and stronger timber in their places insomuch that this ship became a standing example among the philosophers for the logical question of things that grow one side holding that the ship remained the same and the other contending that it was not the same plutarch what does the ship of theseus consist of if it consists of each plank which makes it up then once every plank has been replaced you have a different ship in that case you have to wonder at what point the ship of theseus stops being the ship of theseus so here is a way of thinking about this problem we've got the ship and as we're sailing along in quest of defeating the minotaur uh and doing other things that theseus did well parts of the ship start decaying maybe there's a storm and some things break some timbers break maybe uh some of them just start rotting and we have to replace them uh maybe some of them are starting to age and we realize look we better repair this part of the ship before it starts leaking whatever happens we go along and we repair the ship as it goes we take out some old planks we replace some new planks and we keep doing that sometimes we may have to pull aside and go to land to do that often we do it as we're sailing around in any case we repaired the ship as it goes now you might imagine over time that all of the original lumber gets replaced in this way it might be replaced you know a lot of it at once but it might be replaced planked by plank so that it takes quite a bit of time something similar might have it happen in a fence various pieces of wood that make up the fence deteriorate over time you replace this one you replace that one that post rots out so you have to replace that post and you do this periodically well by the end is it the same fence and similarly here is it the same ship now there's a way of taking this and making it even more cute because we're tempted to say look as long as it's happening slowly enough and these stages are similar enough to one another yeah of course it's the same ship i don't even see why it's a problem to see it more clearly i think we can take a case where there are actually two ships here in fact we have part of this little fireplace display two ships of theseus and so let's take a look at an alteration of this that appears in thomas hobbes the idea is going to be that somebody is gathering up those old planks and rebuilding the ship the idea then is they do this very systematically over a period of years and so we end up with two ships we've got the ship of theseus the one that's been repaired gradually and is still sailing around but we also have this other one the person has been gathering up all the wood of the ship of theseus the original ship and has finally gotten the original plans and has rebuilt the entire ship original planks of wood in the original plan and let's say he displays it in a museum and says the original ship of well which one is truly the ship of theseus one of them and don't be misled here by the fact that it says the ship of theseus and you might say well it's theseus the ship it's the one theseus owns so let's imagine that instead of the ship of theseus we give it a name call it the argo so then which one is the argo is it the one that theseus is still sailing around he says look i've had this ship all the way along and we are tempted to say yeah you've had that ship right it's gone all the way along but then the one in the museum if an object is is aristotle thinks matter plus form it's the original matter and it's the original form how can you deny that it's the original object so which one is truly the argo well you might say only a philosopher would worry about that but not necessarily suppose theseus finds out that the original argo is being displayed in this guy's museum and he says what is this i'm sailing around the argo you don't have the rights to use that you can't advertise that as the ship of theseus the original argo and he sues him so you're the judge and you have to say um okay shoot i have to decide which is the original argo is it the ship that is sailing around still by theseus or is it the ship in that museum it is the original wood and it's built according to the original plan so is it the argo who has the rights to to call it the original argo anyway it's not a trivial problem for example that ship of theseus concerning the difference were made by continual reparation in taking out the old planks and putting in new were after all the planks were changed the same numerical ship it was at the beginning and if some man had kept the old planks as they were taken out and by putting them afterwards together in the same order had again made a ship of them this without doubt had also been the same numerical ship with that which was at the beginning and so there would have been two ships numerically the same which is absurd thomas hopps hobbs is making the puzzle more clear by suggesting that the planks which have been taken out and replaced from the original ship could be used to construct a ship of the same design and in that case you have two identical ships one which is made of the original planks constructed in the same way and the other which is the original ship with each plank replaced so let's think about the general form of this problem and i'm going to do it with something that is an example much closer to my own experiences the camaro of daniel i have not had a ship i have not sailed it around the aegean and replaced planks but this is my first car a 1975 red chevrolet camaro and i kept that car for many many years it gradually deteriorated and parts had to be replaced so there were many things of course tires had to be replaced a variety of engine parts had to be replaced this type of thing that's standard maintenance on a car but in this case there were a lot of other problems as well for a while as a graduate student i had an apartment over a chemical factory in the ohio river nice view however terrible pollution coming out of the chemical factory it ate away much of the paint and caused severe rust problems in the poor camaro even when it was quite young by the time it got older it was held together with aluminum foil and roofing tar believe it or not and so it was a mess anyway finally i got to the stage where i realized i can't drive this car anymore it had become very dangerous three times in one month it had broken down and nobody quite knew how to fix it everything was wrong with it and so i sat there with it the last time waiting for the tow truck to come and take it to the junkyard and somebody came by and said you're getting rid of that car why and i said well look it's got problems the engine is a mess and nobody can fix it and he said well you could get a new engine okay um the electrical system is a mess when you turn on the turn signals the brake lights come on so press on the brake and the fastener seat belt light comes on and the guy said well you could get a new electrical system well but look i mean the body is terrible i mean look at the rust it's held together with aluminum foil well you could get a new body but look the frame is all rusted out it's in turn well you could get a new frame in short he was talking about replacing every part of the car now i said well you're really telling me it's just replace everything in effect you're telling me just rebuild a new 1975 camaro that's ridiculous and so if suppose i had done that would count as the same car intuitively it feels like look if that happened over many many years over the whole the 17 years i owned the car then you might say yeah same car but if it happens all at once you're just rebuilding a new car you're not really building the same car and fixing the same car it's surely not the same after all of that hobbes is pointing out an even greater aspect of the problem because hobbes is telling us look if we have this scenario where theseus has been replacing the planks of the argo bit by bit someone else has been gathering them up we've got a situation where we had one ship here [Applause] let's call that the original argo no problem about that but then as time goes on the planks get replaced so we get various stages of the argo here and now my goodness those uh well it's changing a little bit in the way i draw you but these are boat stages you might say but then somebody else starts gathering up the planks and so they gather planks from this and eventually they produce a boat that is just like this one now this has actually the original matter the original wood from the ship it has the original form it is built in exactly the same structure this one well theseus you might imagine or at least his descendants or somebody is still sailing this around it has a kind of continuity here but it has been repaired and so this is now entirely different matter different wood and presumably it's not entirely a different form but it's probably a somewhat different form he's made repairs and made improvements as he's gone and yes that mast broke so he had to have a new one and the wood isn't exactly the same height and they replaced the sales and these sales are even better and so forth so it's going to be well related but not exactly the same structure we'll say it's a similar structure but of course we can imagine changes that make it look quite radically different if we've done that gradually and so now the question is well at this stage what do we say about this are there two argos so i ask you now is this the argo is this the argument here's the strange thing if the guy had not been gathering all of these up if he had not rebuilt the ship we'd be saying of course that's the argo right this is the way it goes with objects we've got all these argo stages we put them together and called that the same ship the argo but now that somebody's done this we suddenly say but but that is the original wood in the original configuration hmm what's wrong with that picture well it hasn't been done gradually and so you might think that's the thing there's a continuity here so perhaps if la if you're locked you're going to think continuity is the big matter so you're going to think continuity that's what this has this doesn't have continuity now if he had the original plan and was gathering up the wood scr wood gradually and was putting it in this frame gradually and so gradually this replica grew would we then say oh well now it does have gotten oldie so it's okay i'm not sure we've got a number of choices here one choice is to say this is the argo guy loses the suit he has to stop using that name for the boat in the museum because after all really this is the argo that's not we could say as aristotle's theory might tempt him to say actually this is the argo this is the one that is the original matter and the original form this has become a different ship we could be somebody who says well i don't think in this scenario either one is really the argo this is heraclitus view actually you can't sail to the same boat twice let alone step into the same river twice it's going to be different at every stage so this isn't strictly speaking the argo and neither is this one and then you could say actually there are two argos now there's argo one largo two of course they're not exactly the same ship we don't want to identify them but now they're two argos so in short there are four possible attitudes we might have about this this one is the argo that one's the argo both are the argo neither one is the argo and all of those are viable hume's view is actually none of those four possibilities it's still another possibility it's to say look there is no fact of the matter about this question so it doesn't make any sense to say which one is really the argo there is no really the argo it's a question of what we want to say so hume remember about the self had said all the nice and settled questions concerning personal identity can never possibly be decided and are to be regarded rather as grammatical than its philosophical difficulties but it's true about all objects including the ship about the camaro everything all the disputes concerning the identity of connected objects are merely verbal it's a question of how we're going to use words so hume says there simply is no fair standard for deciding a case like this between theseus who is saying i'm sailing the argo and the museum owner who says i've got the argo original wood in the original structure hume just says as the relations and the ease of the transition may diminish by insensible degrees we have no just standard by which we can decide any dispute concerning the time when they acquire or lose a title to the name of identity so in short there simply is no fact of the matter about whether this one's the argo or that one is or both are or neither are we just have to decide so if you're the judge and you hire hume as your expert witness hume is gonna say look i there is no way of getting this case right or wrong there simply is no fact of the matter about which one is the argo we just have to make up our minds about which one is the argo hume says i think most people are going to say in this situation the ship that's theseus is still sailing around is the argo they're going to use lock's criterion of continuity as their way of grouping things together but that's a decision they're making it's not that there is a metaphysical fact this one really is the argo instead they're just saying well yeah gosh um it's most useful for us to be able to treat these objects that are pretty similar even if parts are being replaced and repairs are being made and improvements are being made and so forth we want to say that's the same thing it's pretty useful to us i want to be able to say yeah i live in the same house even if i've added on a room and even if i've replaced the floors and so on and so yeah it's it's easier for us if we say it's the ship still sailing around sorry museum owner you lose but that's our decision because it's useful for us to use language that way it's not because there's a real fact of the matter about what ship really is the argo you

Channel: Daniel Bonevac

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Length: 25min 1sec (1501 seconds)

Published: Thu Feb 18 2021