From Theseus to 66: What the Ship of Theseus Problem Can Teach Us About Highway Identity

The Ship of Theseus is a classic philosophical thought experiment that asks whether an object that has had all of its parts replaced over time is still fundamentally the same object. 

The problem takes its name from the ship that Theseus, a legendary Greek hero, used to sail to Crete to slay the Minotaur.

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The story goes that after returning to Athens, Theseus' ship was preserved by the Athenians, who gradually replaced all of its parts as they decayed over time. The question then arises: if all of the parts of the ship have been replaced, is it still the same ship? Or is it a new ship altogether?

The Ship of Theseus problem has puzzled philosophers for centuries and raises fundamental questions about the nature of identity and change. Is identity based on the object's material composition or on its function? If all of an object's parts are replaced, does it lose its identity and become a new object?

These questions have real-world implications beyond philosophical speculation. For example, they can arise in the context of restoring historic buildings, replacing parts of machines or vehicles, or even in the field of organ transplantation.

But the thought doesn't end there, in fact it gets far more complicated. What if all of the original parts that were removed from the ship over time were collected, restored, and reassembled, would that be considered the Ship of Theseus?

Some philosophers argue that the restored ship would indeed be the original Ship of Theseus because it would contain all of the original parts that were once part of the ship. Others argue that this restored ship would be a new object altogether because it would have a different temporal history from the ship that was gradually replaced over time.

This raises further questions about the nature of identity and continuity over time. Does an object's identity depend on the particular temporal sequence of its parts, or is it based on the collection of parts themselves, regardless of their sequence? If a collection of parts is reassembled in a different sequence, does that create a new object, or is it still fundamentally the same object?

The Ship of Theseus problem remains a fascinating and unresolved issue in philosophy, with different schools of thought proposing various solutions, which is what I intend to do in today's blog.

I'm no philosophizer, but I've always connected the idea in my head that the Ship of Theseus is connected to the identity we place on highways. Anyone who's tried to find the original alignments of Route 66 know that there a lot of parts no longer drivable, but there are also many others still that exist today as frontage roads, local roads, or even other routes. The entirety of the road was replaced by the Interstate Highway System, and in many cases 66 was signed on these freeways before decommissioning, so surely that counts too, right?

While this could apply to indeed any highway, I'm going to focus on the Mother Road in trying to solve this dilemma.

Braidwood, IL has a bypass that was once the final alignment of Route 66 (Today it's I-55), but also IL-53 (shown as ALT-US-66 in this topo map) and IL-129, immediately north of 53 were all once alignments of 66.

So which is the "real" Route 66, the original alignment, or the alignment it had at decommissioning?

One proposed solution to the Ship of Theseus problem is the idea of "temporal parts". According to this view, objects can be thought of as being composed of different parts that exist at different times. Each part has its own identity, and the whole object is a temporal fusion of these parts. Thus, they all are Route 66. I'm not here to say that my opinion on the matter is open and shut or that others might not disagree with me, but I believe there is a another dimension at play here. In effect, these old alignments, are grouped into a bucket of sorts, call it the 66 bucket, and as such, coexist simultaneously with each other. Assuming you could re-create the old parts of 66 into a completely different alignment (you can't, not entirely), you would have two completely non-identical 66's. 

Applying this solution to the problem of the Ship of Theseus, we can say that the ship is a temporal fusion of its parts over time. Each individual part has its own identity, and the ship as a whole is a composition of these parts at a particular point in time.

But of course, Route 66 has been immortalized by road enthusiasts and popular culture. There are quite a few routes that, for one reason or another, don't hold the claim to fame that 66 does, some are even infamous, like the Embarcadero Freeway, as one example. So I think there's a bit more than just temporal parts at play here, and I apply this same logic to the Ship of Theseus. 

Give any random ship random parts, and re-assemble those parts in other ships, and they're part of a different bucket. The only reason the parts of a Ship of Theseus are worth more than their sum of their parts, and indeed would even continue to be after being part of the Ship are because it is named, because there is some history behind it that humanity has bestowed upon it. It's why people have bricks of the old Chicago Stadium and bleachers from old baseball parks in their garage, but most likely don't have the old bleachers from the local little league park. 

Old Wrigley Field Seats

The Ship of Theseus parts are more than their sum and could be reassembled into another Ship of Theseus because we as humans perceive them to be, just like the idea of Route 66 is far more than its individual parts.

I hope I didn't bore you all too much with my foray into philosophy, but it's been a concept rattling around in my head for far too long to not write about!

The Route of Theseus is a related concept that can help to further illustrate this idea. Just as the Ship of Theseus is composed of different parts over time, a road or route can also be thought of as being composed of different sections that exist at different times. For example, a road may be widened, repaved, or rerouted over time, with new sections replacing old ones.

However, even though the old sections may no longer exist as part of the current route, they still exist in some sense. They may be repurposed as local roads or given historic status, for example. Thus, we can say that the old sections are temporal parts of the current route, just as the old parts of the ship are temporal parts of the current ship.

This view helps to solve the problem of the Ship of Theseus by acknowledging that objects are not static, but rather are composed of different parts that exist at different times, and given meaning by humans based on historical status or popular culture. By recognizing that the identity of an object is a temporal fusion of its parts, we can see that it is possible for an object to change over time without losing its identity.

NOTE: This blog was written in conjunction with Medium, which I am testing the waters for to see if I'd rather move to that platform. Let me know what you think!

Thanks as always for reading!