After a long and arduous evening of work, I collapsed at home on my bed. While I considered whether I should shower and possibly play a little Minecraft, or if I should pour myself a stiff nightcap and call it a day, I instead decided to open Twitter. One of my favorite people that I follow, Britni Pepper, commonly writes and tweets about philosophy, at least when she isn’t engaging other authors or pointing out the numerous flaws of the United States. Something, I cannot remember what, sparked a thought in my head. And as I made my decision to get a shower, I was able to grow that thought inside the world’s greatest, steamiest meditation chamber. Perhaps paradoxically, science and philosophy have always been key interests of mine. So if you would, please join me down an interesting rabbithole I conjured up while having some deep #showerthoughts.
The “Ship of Theseus” is an age old thought experiment in philosophy about the nature of identity. One side of the experiment goes something like this: after years of battle and heroic deeds, Theseus’ ship is to be decommissioned and kept as an artifact for a museum. However, ships of this age were made of wood, which will eventually succumb to the passing of time. It could be due to rot, insect activity, etc, but wood is not around forever. So in order to keep this important symbol and artifact on display for future generations, caretakers must replace beams, planks, sails, and rigging over time. After centuries, every individual part of the ship will have been replaced as part of its ongoing restoration. The question now arises, is this still Theseus’ ship on display? If so, by what definition is it, when all of its materials aren’t original? If not, why? When did it lose its identity; if it has been properly restored it should be indiscernible from the original, even to Theseus himself. This is the sort of thing many people thought about before we had the internet and television to distract us between meals and working hours. Contemporary philosophers in the current day still muse over this quandary.
But now let’s take this idea from the abstract to reality, and to a potentially uncomfortable place: YOU are the Ship of Theseus. Kinda. While this analogy isn’t perfect, inanimate objects are restored and maintained over the course of multiple centuries. Even with modern medicine and agricultural surpluses, much less than 1% of people in the US will live one century. However, many highly important parts of your body will be replaced and recycled over your lifetime. Your skin, blood, internal organs, even your bones aren’t made of the same sets of cells they were made of a week ago, or will be a week from now (barring an untimely death, I hope).
One key exception to this regenerative process: the brain. Brain cells are mostly formed prior to birth, however, that doesn’t mean you can’t create more. Throughout childhood and adolescence, you grow new brain cells. In adulthood, this growth slows, and gets worse with age. Eventually it is possible to reach a point where new ones are not being generated at a rate higher than they are lost.
The key Ship of Theseus question here is: what makes “you” you? You may not have asked to have your stomach replaced, but your body did that on its own about a week ago. If almost all of the cells that keep you living have been swapped out multiple times over you lifetime, how can you claim those body parts to be yours? It would seem as if our brains are Theseus’ masthead, only made of stainless steel as opposed to the other wooden parts. It may tarnish over time, but not to the point of needing replacement.
So that’s it, the fact that we do not replace all of our brain cells over our lifetimes sinks (eyyy) this comparison to the Ship of Theseus, right? I’m not entirely sure of that. Because while the actual physical building blocks remain largely the same, people still change mentally over time. Science has shown how memories, even intimate ones, can erode and change over time. Sometimes we implant false memories, without even knowing it. This is something that makes the justice system a bit dicey, since most witness testimony is based on memory. Furthermore, your experiences, values, tastes, and personality continue to change over time. These seem more important to trying to define “you” than the ever-changing number of atoms that make up your body. If 5 year old me loved raisins (I ate them almost exclusively) but 25 year old me hates them (rightfully), does that mean past me isn’t “me”? I would argue that just as the cells in your body change over time, so to does your identity. You constantly have a very tenuous grasp on what gives you that sense of yourself both biologically and psychologically. It seems to me that your entire life is one free-flowing transition from one identity to another, the sum total being the story of you. And I’m not even going to touch the idea of “souls” because that is another can of worms that I do not want to open.
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HMS Victory is in Portsmouth. She was 47 years old at Trafalgar, and had already been through several major battles, quite apart from the daily toll of simply being at sea. After 1824 her sailing days were over, but she was afloat and in use for another century. Since 1922, she has been in drydock and constantly being maintained and repaired.
How much of her was at Trafalgar, let alone launched in 1858?
Zero, is my guess. There may be a few metal artifacts that are original, and maybe a few pieces of her keel, though I think she is largely concrete down there.
I was aboard her many years ago, and saw the place where Nelson fell. Legend has it that he tripped over the plaque at that spot.
I would say that the notion of HMS Victory is similar to the notion we have of ourselves. And of others.
How do you recognise someone else? You wake up one day and see another person. Your spouse, your busdriver, your boss, your dog. How do you identify them and assign the role and qualities afresh?
Yes, there are physical signals, but you are not comparing their physical resemblance to a photograph or a marble bust to say “G’day, Jay! Owyergoinmate, alright?”
You have a copy stored in your memory, and you compare the person against the copy. It might not even contain any visual elements. We recognise people on the other end of the phone, or maybe just the individual texture of mind that is reflected in their choice of words.
I remember meeting for the first a person I’d spoken to many times on the phone. He had the broadest of Australian accents but in person, he was entirely ethnic Chinese. He laughed at the expression on my face as I mentally readjusted my internal image; he had seen the same expression a thousand times before on a thousand different faces.
But I knew it was him. I recognised the texture of his mind.
Which raises the question of how I could do this without having a copy of his mind – or at least its texture – inside mine to compare it against.
So. Where does the truth lie?