What Are You?
The Theseus Paradox explained.
Stuart stepped onto the platform of the teleportation device and disappeared. Nobody batted an eye.
An instant later, he appeared halfway across the world, stepped off of the device’s platform, and went about his business.
Is Stuart still Stuart? I mean, if that was all the information I was given, yeah. I would say so.
What if I told you, though, that when he first stepped onto the platform and disappeared, the teleportation device ripped apart his body, atom by atom. The atoms that made up Stuart simply dispersed into the air. He disappeared and on the other side of the world, he was assembled, atom by atom. Atoms were pulled from the environment on the other side of the world and the exact location of every electron in every atom was identified. In fact, the science was so exact, Stuart’s neurons were arranged and categorized so that the human stepping off of that platform had every memory of Stuart’s, up until the very moment he disappeared.
The Stuart that emerged on the other side of the world still loved his wife. He still liked to eat a bowl of cereal every night before bed. He was still in the middle of mourning his recently deceased father.
But is this Stuart still our Stuart? Or is this human just an imposter with Stuart’s memories? What a conundrum.
This quandary is described by the Theseus paradox. A hero of Greek mythology, Theseus supposedly founded the city of Athens. To memorialize him, the people of Athens preserved his ship. Throughout the hundreds of years, though, the wood itself started to rot. The people decided to replace one rotting plank with a new plank made of the exact same material, then another, and another. This brought about the question of whether this ship was still the ship of Theseus. How many planks needed to be replaced before this ship was no longer the ship of Theseus? At what point did the ship, as a whole, change?
The Theseus paradox fundamentally calls into question the problem of identity. What even is the ship, really? Is the ship a collection of planks? But how can that be if the ship is no longer Theseus’ ship when enough planks have been changed?
It may be easy to write off this problem by claiming that this ship is no longer the ship of Theseus once 50% (or some arbitrary percentage that makes sense to you) of the planks have been replaced. I challenge you, then, to consider this same example within the context of a human body.
If you have a kidney transplant, are you still you?
If you have a kidney transplant and a heart transplant, are you still you?
What if you have a kidney transplant, a heart transplant, and two dozen more transplants? Are you still you if your entire body is a collection of strangers’ organs?
Let me present a final nail to this coffin.
It is a fact that almost every cell replaces itself in approximately seven years. Forget about this absurd hypothetical situation in which your entire body is made up of different cells. You already are, essentially, a different person every decade. What defines you, then, if even the cells that make up your body are replaced just like Theseus’ ship?
Ultimately, like many other philosophical questions, paradoxes like these do not really plague us. We go about our lives after some consideration of what makes up something if everything can be replaced. The Theseus paradox deserves some extra consideration, though.
For example, the Theseus paradox proves the fault of a “bring the old days back” sentiment. The existence of this paradox proves that there is an inherent contradiction in building an old ship with new planks. It shows that no matter how hard we try, we can never go back.
In a similar vein, the Theseus paradox encourages people to take a closer look at developing technologies. For instance, Humai is a technology company with plans to transfer human consciousness into bionic bodies. Though this technology is still years ahead of our time, it's coming. And the Theseus paradox brings about an absolutely crucial question: are you still you in a bionic body?
Stuart’s identity might also be in jeopardy. The teleportation of humans is still far off, yes. But in 2017, Chinese scientists were able to “teleport” photons to a satellite 300 miles away, using a phenomenon called “quantum entanglement.” Dematerialization and rematerialization may certainly become possible one day.
When that time comes for Stuart, I hope we were able to find out how to preserve what makes Stuart, Stuart. I hope that this teleportation box is indeed a teleportation box, rather than a suicide box that rematerializes a carbon copy of Stuart. I hope the real Stuart is the one who walks out of the teleportation device. And for that to happen, I hope we find the answer to the most fundamental question of them all.
What are you?
Because we can’t preserve you if we don’t even know what it is that makes you, you.
