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The Ship of Theseus

David Cowles

Jul 15, 2023

“There is only one I am, shared by YHWH and Jesus…and me…and you…and Rene Descartes (…ergo sum).”

It’s one of philosophy’s oldest riddles. Time and tide being what they are, the Ship of Theseus requires constant maintenance, and sometimes that maintenance requires us to replace rotten wooden planks with fresh lumber.  

At some point, presumably, none of the original wood will remain. Is the vessel then still the Ship of Theseus? Or is it now a brand-new vessel? If the latter, at what point in the gradual replacement process did the Ship of Theseus cease to be the Ship of Theseus? When the first board was replaced? When the last of the old boards was removed? Or at some arbitrary tipping point (e.g., when original material constituted less than 50% of the entirety)? 

Of course, the standard ‘solution’ is to say that the ‘Ship of Theseus’ is the vessel’s pattern (its Platonic form), not its materials. But this raises a new problem: we can build a dozen copies of the original Ship of Theseus, and the original and its copies will all share the same form.  

Must we then say that they are all the Ship of Theseus? If so, then we have converted a proper noun (‘Ship of Theseus’) into a common noun (‘ship of Theseus’); what would Sister Margaret have said about that? 

But this is not just a matter of grammar! By converting ‘Ship of Theseus’ to ‘ship of Theseus’ we have moved from a unique, discrete, material object to something immaterial and conceptual, i.e., to a ‘class of objects’ (whatever that may mean). In other words, ‘Ship of Theseus’ and ‘ship of Theseus’ are even less alike ontologically than they are grammatically. Not to put too fine a point on it, but they have nothing to do with one another!  

Perhaps a problem shrouded in the mists of mythological time isn’t compelling your interest. How about something closer to home then? How about your precious body, yup, that body - the one you build on weekdays at the gym and polish on weekends at the spa?  

That body is made up of more than 30 trillion living cells, virtually none of which you’re directly aware of. These cells have an average life expectancy of 7 years. Therefore, your body, like the Ship of Theseus, is undergoing perpetual replacement. So then, when are ‘you’ no longer you

Another problem. You were conceived at the fertilization of one ovum by one sperm cell. One particular ovum, one particular sperm. That’s you…sort of. But what if the same act of intercourse between the same two partners (your biological parents) resulted in the fertilization of a different ovum by the same sperm cell, or the same ovum by a different sperm cell, or a different ovum by a different sperm cell? Would ‘you’ still be you? Or would you be the sibling of the person you otherwise might have been? Dizzying! And we’re just getting started. 

Whoever you are, you have millions of virtual siblings (potential combinations of sex cells from the same two partners) and maybe a handful of actual siblings. However much you may share traits with these siblings, virtual and actual, the truth is that you’re not the slightest bit like any of them. You are you, and they are they; you’re not they and they’re not you. The ontological gap between you and your sibling, even your identical twin, is well, not to exaggerate but… it’s infinite. 

And don’t get me started on astrology? What if you’d been conceived a minute earlier…or a minute later? What if Mercury just went retrograde? Who and what would you be then

Obviously, this is an unsatisfactory situation. It results in a proliferation of entities that would make even Ptolemy uncomfortable, not to mention William of Ockham – you know William, lead vocalist for the heavy metal band, Occam’s Razor

The alternative is to accept the uncomfortable conclusion that each human individual is a unique, emergent phenomenon, ontologically unrelated to any other phenomena, actual or potential, no matter how apparently similar they may be. But this ‘solution’ has its own issues.  

I am looking out at the audience during a lecture I’m giving when I notice that about half a dozen of the folks are, like me, a bit on the ‘plump’ side. I am tempted to say that ‘plumpness’ is an attribute we share but that would be wrong. Each of us is plump in his or her own way. 

Plumpness in me is unrelated to plumpness in you. My doctor has just put me on a strict ‘heart healthy’ diet while you’re carbo-loading for a part you’re playing in an upcoming film. It is thanks to human rationality and ‘the language tool’ that a concept like ‘plumpness’ can be abstracted from a handful of unrelated phenomena to become the description of a certain imaginary class of objects. In fact, each of us is what we are, as we are, i.e., in our own ways.  

Phenomena (parts) derive their meaning from phenomenon (the whole). You and I both have a small dark spot on our left cheek. For one of us, it’s a cosmetic beauty mark added by a beautician during a recent spa visit; for the other, it’s melanoma.  

Something has meaning only in reference to something else. Therefore, any whole, considered in isolation, is meaningless. The parts of that whole, however, do have meaning, first with respect to the whole, then with respect to each of the other parts of that whole. An entity, any entity, is an information matrix. “It from bit.” (Wheeler)  

Wholes seem to be made up of interchangeable parts, but the meaning of each such part is entirely determined by the unique whole to which it contributes. Therefore, no two parts, no two wholes, are ever identical or interchangeable. 

Peeling away the layers of this onion is tough work for a sensitive guy. Tears are already streaming down my cheeks, and I have one more, crucial layer left to peel: If you and I have no parts in common, then there are no parameters according to which we can be compared. 

“Why can’t you be more like your sister?” is not a thing after all! You are you, and she is she; the two of you are neither alike nor unalike. Like implies comparability and you two are, believe me, ‘incomparable’.  

“I am what I am, and that’s all that I am.” (Popeye) Likewise, you are what you are, and that’s all that you are. You are not ‘like me’, nor are you ‘different from me’. We are ourselves alone. 

But the caterpillar, as always, must have the final word, “Who R U?” Because ‘what you are’ and ‘what I am’ have no axes of comparison, ‘who you are’ and ‘who I am’ must be the same thing. It’s just ‘who is’. In the Book of Exodus, YHWH says, “I am.” Who or what? “I am who am.” (Exodus 3:14) 

The Gospel of John echoes Exodus, but this time it is Jesus speaking, “I am.” Again, no predicate! John’s point, of course, is that the ‘am-ness’ of YHWH and the ‘am-ness’ of Jesus are one and the same. There is only one I am, shared by YHWH and Jesus…and me…and you…and René Descartes (…ergo sum).  

Because none of us has any ‘identity’ per se, we are all merely manifestations of a single process – the process that recognizes potential ‘parts’ and uses them to build novel ‘wholes’. We are children turned loose in a junkyard, looking for parts we can use to make a soap-box for an upcoming derby. 

No two wholes are the same, no matter how similar they may look; neither are any two parts. But the process by which parts become wholes is unitary…and universal. So ‘me being me’ and ‘you being you’ are one and the same thing; even though (actually, because) ‘what I am’ and ‘what you are’ have no axes of comparability.  

So questions like, ‘would you be the same person if…?’ have no meaning. Who you are is immutable…and coincident with Being itself; what you are is entirely contingent. You are who you are regardless of what you are. This is why you can never escape yourself, no matter what you may make of that self.   

But who you are is neant (Sartre). Who you are is not-being what you are. You are process, the perpetual process of not being what you are, of coming to be what you are not. Perpetual, of course, because you never reach your goal: you never become what you are or what you are not. In the words of the pre-Socratics, who you are is Aletheia (Parmenides), timeless and featureless. What you are is Panta Rei (Heraclitus), ‘everything flows’. 

“Life is difficult” (Scott Peck). You are not God. Being terrifies you; you are in free fall. Your arms flail as you reach for a handhold to break your fall; there is none. The underside of life is your perpetual effort to bury who you are in what you are: 

“I’m a big boy now, I’m in middle school, I’m a teenager, I’m in college, I have a career, I’m someone’s significant other, I’m a parent, I’m on the Board of Selectmen (sic), I’m a grandparent, I’m retired, I’m at rest (Rabbit)…I am dust.” 

What you are is always just exactly what you are, but it is never who you are! You are not like anyone else; you are everyone else.     


Image: A Fresco from Pompeii depicting Theseus and Ariadne escaping from Crete. According to Plutarch, the Athenians preserved the ship that Theseus used to escape, by replacing the parts one by one as they decayed.


David Cowles is the founder and editor-in-chief of Aletheia Today Magazine. He lives with his family in Massachusetts where he studies and writes about philosophy, science, theology, and scripture. He can be reached at


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