Personal identity – a quick and dirty look through the lens of philosophy

Our personal identity is something we are bound to question throughout our lives. But beyond simply who we think we are, and what kind of person we want to be, how do we even know what makes us, us? What changes can we go through before we cease to exist anymore?

What is identity?

BODY

You might say, I am my body. I am whatever form I exist in – whatever sustains my life. Sure, my bag of flesh changes throughout time bit by bit, but it is always mine. Without my body, I would cease to exist.

We almost certainly need our bodies to exist in this world, but is that all we consist of? All we are? Can it change without changing who we are?

There was once an ancient Greek ship, called the Ship of Theseus. Theseus and his crew returned from Crete, the historian Plutarch tells us, and the Athenians preserved it as best they could. So, piece by piece, sails and all, every part of the original ship was replaced as it became damaged. No original piece was left.

Is it still the Ship of Theseus, asks Plutarch? Or did it change at some point along the way?

If you feel it is the original parts that make the ship what it is, then you would say it is no longer the Ship of Theseus. However, if you feel it is the idea or function or the soul of the ship that is more important, you might say it lives on in its new parts.

What if, philosopher Thomas Hobbes many centuries later asks, out of all those original pieces as they were replaced by new ones, we crafted another ship? So, there are now two ‘new’ ships; one rebuilt out of the original planks, and the other in which the original planks were replaced with new ones.

Which ship is the Ship of Theseus? The one rebuilt from the ground using the original parts, or the one that was slowly changed into new parts? Or are both ships the Ship of Theseus?

I am going to digress quickly to explain an important idea; numerical identity.

A stranger walking past my car would refer to it as a Subaru Liberty, but I would call it the subuwu. A stabbing pain in my leg, and the biophysical and chemical processes that occur, are one and the same. Many authors also go by pen names, or people have nicknames. But they are one and the same thing. There is a numerical identity, not merely a similarity between two things.

Coming back to our ship now, where we have two physical ships from the one original, can you now see the potential problem? It’s not quite easy to say which one is correct, if any at all. I mean, we would surely not say both ships are the Ship of Theseus – how can we have two ships identical with the Ship of Theseus, when by a matter of logic, we can only have one? Perhaps the Ship of Theseus died altogether as it was pulled apart, and both ships are something else entirely. Remember this concept, I’m going to come back to it.

Bah humbug, you say. Those are about ships; they are inanimate objects and can’t be used as a comparative to identity in humans, you might say to me. It is the idea of you, or your functions, or personality, or your soul that is important, you might say.

Agency seems important. So, if we are not our bodies, are we our minds?

MIND

First posited by a philosopher in the 17th century called John Locke, what keeps you the same person is what he called psychologically continuity.

For you to continue to exist over time, you must have psychologically evolved from your previous self. For example, I remember going grocery shopping last week and buying food to make a Mexican-style bean and rice dish (which was very popular with the housemates when I cooked it for dinner two nights later). I would be said to be psychologically continuous with that person. I can change over time, so long as I can trace that change within my mind, unlike perhaps the Ship of Theseus.

It seems that perhaps memory is essential then; we are our memories.

But there could be some issues.

I have a range of hazy memories from my childhood. But sitting here and thinking about it, I cannot clearly piece together in my head, my psychological evolution through time.

I just can’t fully remember who I was.

But I feel pretty certain 5-year-old me is or was me. I am, at best, connected to that person, but there is no continuity. I mean, who has my mum been raising then?

What about people with memory loss, like severe amnesia? Are they no longer the same people because they can’t remember their past selves? Their persistence over time has likely been broken and have potentially become qualitatively new people. But this still doesn’t quite sit right – perhaps we would still want to say they are the same people, in some way.

Let’s take it in another direction.

Let’s travel an indiscernible amount of time into the future. The human mind is understood in all its complexity. Computing storage and power has come a long way and we have the ability to seamlessly and perfectly upload a person’s mind to a computer.

We hook you up to the computer and duplicate your mind. A digital and complete copy of you now exists on this computer, talking through speakers and saying the things you would. It knows every part of you, every terrible and elating memory. Every intrusive thought and epiphany.

This means it would necessarily also have psychological continuity with you.

So now there are two of you…is that possible? Or is one of you, more you? Does one cease to be the true you at the time of the upload? Are we comfortable for one person to become two?

Maybe you might say that a computer could never capture a human soul. Maybe you might say that there is more to us than our memories and beliefs and dispositions – so you reject psychological continuity. It seems quite difficult to qualify what is important for our identity to stay intact through time. You might even start to reject this silly notion of identity altogether; you would not be the only one.

So instead, I propose the fun thought experiment of fission to keep you distracted. We spoke earlier of the paradox of the Ship of Theseus – so let’s apply that to you.

FISSION

What if, with our amazing advances in technology (think of Black Mirror type whizzbang stuff), we transported you – taking you apart atom by atom, by quarks and leptons, and rebuilt two of you, on different planets in the universe.

As in, from the original you, you were ripped apart, copied, and now two of you rematerialized on different planets. They are both identical with the original you before the transportation, they are the exact same. Both of you, feel like you. You both exit the transporter, put on a spacesuit and begin your day on your respective planet.

But here, the original problem raised with the Ship of Theseus applies here too. It is a paradox. If both copies are identical with you, by a matter of logic, they cannot then be identical with each other. How can something be one and the same, with two things? The reason why both copies are not truly identical with each other despite it seeming so, is because they occupy a different space. You are on two different planets.

Okay, so perhaps the transported “you’s” may not have this strict sense of numerical identity. But they are still perfect copies of you. They are you, without qualitative distinction I argue.

So I have to ask then, if you feel one of you is not the true you, if I killed one of these two “you’s”…have you died?

Or was your original identity ‘killed’ when you were completely destroyed – thereby ceasing to exist for a time – and remade by the transporter?

I shall leave you two here with that thought lest we fall any further into the rabbit hole that is the philosophy of mind.

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Much of this content and more I learned about in greater detail in PHI3VRP – Virtual Reality as Philosophy.

If you are interested in this kind of stuff; how virtual reality, empathy machines, simulations, and the idea of uploading our minds to a computer impact our perceptions of not only our identity, but our reality and how we relate to others, then I highly suggest you enrol in this class run by Yuri Cath. Perhaps you might find an answer to my final questions.

I also highly suggest PHI3MBM – Minds, Brains and Machines, which deals with issues such as the hard problem of consciousness.