The Sword and Laser discussion

I don't know if Tom and Veronica will see this before the next episode is recorded, but they didn't mention the one place in the real world where the ship of Theseus is relevant - classic cars. There are rules about how many parts can be replaced before it is no longer the same car.

I’m not sure that’s an exact analogy. I grew up in Dayton, Ohio, which Hot Rod Magazine called the Hot Rod capital of the world (there were probably several cruise-ins tonight), and different car clubs have different rules, some of which align with legal definitions and some which don’t.

In some states all you need is an original VIN plate for the car to be considered the same vehicle. Unless the law has changed in Ohio, you also had to leave the windshield and doors unaltered for the car to legally remain the same. If you change those, you either have to crash-test the car, which kind of defeats the purpose, or call it a kit car, which kills the resale value. That’s why you see those weird-looking 1950s/60s Corvettes that have the proportions of a modern Vette - they didn’t change the passenger compartment, doors or windshield.

These are all restomods using modern C6 or C7 models as the base. The bottom one is a serious ship of Theseus, with only the VIN plate and engine block remaining.



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Sheeoot, I remember being the distance-running striver of my high school years. That's long gone. About the only thing that's expressed the same is interest in SF. Still feels like me all the way through.

John (Taloni) wrote: "Sheeoot, I remember being the distance-running striver of my high school years. That's long gone. About the only thing that's expressed the same is interest in SF. Still feels like me all the way t..."

The illusion of continuation of consciousness.

Trike, I'm definitely more on your ground than mine, so I'm yielding ot your expertise. I think I'm going based on the rules of a car club that was near me which was much more strict on how much could be retrofitted vs what the law says you can do. That said, it was many years ago and it's possible either I misremembered or the person explained it backwards to me.

Eric wrote: "Trike, I'm definitely more on your ground than mine, so I'm yielding ot your expertise. I think I'm going based on the rules of a car club that was near me which was much more strict on how much co..."

It does bring up an interesting question that I never considered before, namely that some parts of vehicles *have* to be replaced. Whether it’s a ship or car, we still swap things out constantly. Tires, sails, brakes, anchors, belts, ropes… back in the day there was more, like plugs, points, carburetor parts, even seatbelts. I can’t even recall the last time I had to replace a spark plug or seatbelt.

Do we count those bits, or are they in a separate category?

Related: here’s a video of a cruise-in in Dayton uploaded just a few minutes ago.

https://youtu.be/nraCbkIU4WE

The ‘69 Mustang at the start is a case in point: highly modified by the guy who’s owned it since new, but he still has all the original parts so he can restore it back to its factory state.

Ship of Theseus reversion? Or is it Schrodinger’s whip, existing in both hot rod and stock form?


(When we lived in Cincinnati I once said to my father-in-law, “I saw there’s a cruise-in at the Roy Rogers.” He, not originally from the area, replied, “I don’t know what those words mean.” 😆)

Well, that Mustang example does make me think of a corollary of the Ship of Theseus paradox that I remember learning one of my undergrad classes.

IF you accept that the ship of Theseus is still the same ship if you repair it one piece at a time, what if you don't wait until it's falling apart? What if you save each piece and at the end build a second ship with all those parts? Do you now have 2 ships that have a valid claim to be The Ship of Theseus? Why or why not? And if not, what does that say about the original paradox.

Also, if anyone else joins our thread here - see the related Heap Paradox because it's somewhat key to the corollary. (Other versions include the balding man paradox and the rich person paradox) They all result in saying that neither end of the spectrum can be true. For example, if you take a rich person and subtract one penny - are they still rich? Of course! And you know, OBVIOUSLY, that someone with no money is poor. But at what point along the spectrum can you say that someone isn't rich without it sounding ridiculous that one penny makes a difference.

The way this relates to the Ship of Theseus (and ending up with 2 of them) is that it would be ridiculous to say that replacing one plank makes it no longer the same ship. But what after what plank is it no longer the same ship? Can you say with a straight face that merely swapping this plank changes things? And you can also argue it down to the nails or something smaller ot make the point.

In the real world where it matters they usually set a percentage. Not to bring politics into it - but just how much % of something has to be made in the USA to be a USA product is usually a number smaller than 100%. Or in the case of the car example t hat Trike mentioned - they just say you have the VIN plate and that's it.

Eric wrote: "it would be ridiculous to say that replacing one plank makes it no longer the same ship"

Or is there one plank that is the essence of the ship? As in Friends when Joey took the cushions from the chair and Chandler complained, “The cushions are the essence of the chair!”
https://youtube.com/shorts/DOKyeyOHjO...

In the old Atari game Warlords there was a spot we called “the key brick”. If you hit that, you destroyed the opponent’s castle immediately. You can see it happen here with Green at the 15-second mark. https://youtu.be/Zu3DYHm7qlw That was the essence of the castle!

Trike wrote: "Eric wrote: "it would be ridiculous to say that replacing one plank makes it no longer the same ship"

Or is there one plank that is the essence of the ship? As in Friends when Joey took the cushio..."

Great points! Especially if you're reading books in the sword part of Sword and Laser. Although maybe you could say that the exhaust port was the essence of the Death Star?

Eric wrote: "the exhaust port was the essence of the Death Star"

😮 🤯

Have we missed a trick by not implementing a twins study...

Iain wrote: "Have we missed a trick by not implementing a twins study..."

I don’t think transplanting organs into a healthy person is ethical, Iain.

Trike wrote: "Eric wrote: "it would be ridiculous to say that replacing one plank makes it no longer the same ship"

Or is there one plank that is the essence of the ship? "

An engineer might think of it like this.
If a model or equation is complex you can perform a sensitivity analysis where individual inputs are changed by a small amount (delta lowercase) and the magnitude of the change in output compared to the baseline.
Consider all the components of the ship as inputs in a complex model. Assume swapped components are not actually identical so there is a small change to the input and therefore the ship performance.
Maybe some components have only trivial effect on ship performance but some have a larger effect. Like the essence plank.
If changing a component passes a defined threshold on ship performance difference then the ship performs 'differently' and is now a 'different' ship. I've had to define 'different' here, neatly making sure that anyone with an alternative notion of what 'different' should mean is now 'wrong'.

Of course components change with age too. So from second to second the ship is not the same ship 'physically' because it has changed.
This is also true of Mickey.

Philosophically there is no answer. It's just something to debate endlessly while getting sozzled at a symposium.
This is probably why philosophers are more likely to get invited to dinner parties than engineers.

Pumpkinstew wrote: "Of course components change with age too. So from second to second the ship is not the same ship 'physically' because it has changed."

Entropy causes things to no longer be the same? So is there a point where a thing is no longer itself?

With living beings, I suppose it’s when one dies, or perhaps has enough limbs and organs replaced a la Bionic Man/Cyborg the DC superhero. For a house fallen into disrepair, when it no longer provides shelter for humans, even though it might still function as shelter for mice. Which brings us back to Eric’s point:

Eric wrote: "In the real world where it matters they usually set a percentage."

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