The ship of Theseus

The answer to this philosophical question holds profound implications for a number of scenarios. It aims to answer the question: when does something stop becoming itself? It was first introduced as a philosophical question by Plutarch.

I will try to highlight the main point of the question here. There was a ship created by Theseus that went on a legendary journey in Greek mythology. Upon completion of its journey, it was returned to Athens and used for several years thereafter. Over the years, due to normal wear and tear, different parts of the ship were replaced as needed. At some point, there was not a single piece of wood from the original ship remaining. Would it still be fair to call the ship “the ship of Theseus”?

Why is this important?

It might be difficult to understand how this question relates to modern life. I will try to provide a very high-level and imperfect comparison. If the mind has been uploaded to a computer, would it still be you? Similarly, at what point does a fetus become a person? How much change needs to happen in order to cross the threshold where a new term has to be applied? At what point is the child his own person? There are obviously other, much less severe comparisons that could be made, but I hope I have convinced you of the importance of why this question needs to be answered.

The key point is to identify how much change is needed before something can be called by a different name. In nature, a caterpillar can be called a butterfly after it emerges from its pupa. In life, things are not as clear-cut, and therefore we need a metric against which we can evaluate things and make decisions.

A nuanced approach to understanding this question is to ask the following two follow-up questions:

• Is something a thing because of its own attributes?
• Or is something a thing because I say it’s a thing?

This is at the core of abortion laws, trying juveniles as adults, and many other social/ethical quandaries we face.

The Objective Argument

In order to answer this question, I have taken a slightly different approach. The stakes are less severe when you consider this an ethical dilemma related to a ship. To come to a clearer answer, I have decided to replace the ship with a person. This would be unthinkable in Plutarch’s time, but in today’s world, medicine has evolved to the extent where a number of human organs can be replaced. So, I would like to answer this question in the following terms.
Would you still be the same person if your heart was replaced? I think the obvious answer is yes since we already have living proof of many examples where the heart has been replaced. Similarly, we can also replace the kidney, eyes, and any other important organ except the brain.
I think we can all agree that what makes us “us” is what happens in our brains—our memories, our ideas, our personality are all tied to our brain. A logical extension of this approach would be to ask what makes a ship a ship. I would argue that you can take the sail of a ship away, and it would still be a ship. You could take away the oars, and it would still be a ship. But if you take away the hull, then I doubt most people will be able to call it a ship wholeheartedly. So, it would seem the answer is to identify the attribute that makes the object what it is, and as long as that attribute(s) has not changed, it retains its originality
At this point, I should introduce some caveats. A brain inside a dead person no longer has its memories or personality, and therefore that person is no longer the original. At least not physically. Human sentimentality attributes a lot of the emotional association to the physical body long after it is dead. But for all intents and purposes, the person no longer exists, so a dead Jayanth is not “Jayanth”. Understanding this approach will open the doors for organ donation and other cases where progress is stalled by sentimentality.
It will be interesting to consider another aspect of this discussion. It can be established that someone else’s brain with your memories is you and vice versa. How do we tackle this scenario where your brain has been uploaded to a computer? Since the computer holds your memories, by the strictest interpretation of the paragraph above, it is you. This deviates significantly from our humanity by forcing us to attribute emotions to a machine, but it does not violate the above principle. By transferring your brain onto a computer, you have now reached a point where the computer makes decisions and has utility; therefore, it is an extension of you and is therefore you.

To extend this argument further, let us assume it is possible to copy your brain such that both your physical body as well as the computer are replicas of the same brain. In this case, it is possible to universally agree that the original physical human being is the source, and the computer is the target, and therefore by nature of causality, the human being is the original and the computer is the replica. As long as both have utility, the original human being would continue to be the universal manifestation of “you”. Once the original ceases to exist, the replica becomes the new original. You can easily extend this argument to parent-child relationships as well, but that is a convoluted argument. Take cases where there are multiple children, for example. They can all stake a claim to being the original unless some temporal hierarchy is established or the parent has deemed a child to be his true representative (religion and politics are filled with such minefields). Even if temporal hierarchies are established, this argument fails in the event the children are twins or birthed by artificial insemination.

We can extend this argument further to establish that a person who has had amnesia is no longer the person they were before the incident happened. Simply because by definition, what makes us “us” is our memories, personality, and all the other trappings of our brain. And as such, if the brain is no longer what it used to be, it is no longer that same person. Essentially, this would be the argument for Theseus’s ship: if the wood of the hull is the same, then it is still Theseus’s ship, but if the hull itself has been completely replaced with new wood, then it is no longer Theseus’s ship.

The Subjective Argument

So far, I have laid emphasis on only the object ship and have based my arguments purely on what makes a ship a ship. It would be unfair to close the argument here because this is no ordinary ship; it is “Theseus’s ship”. While the ship’s hull remains the same, if it has been written off to somebody else, it no longer remains Theseus’s Ship.

We already know what makes it a ship: its hull. But what makes it Theseus’s is the fact that “he” made it. As long as we attribute Theseus as the creator of the ship, it is “Theseus’s ship”. Even if the ship has been sold to another person, as long as it is referred to as “Theseus’s ship,” it remains the original. Now we replace the memory of a person (from the previous argument) with the history of the ship. Simply put, the preservation of the memory of the ship and its adventures is why it is Theseus’s Ship, not the hull, the oars, or any physical attribute of the ship itself. This definition has ramifications for trademark law, especially when brands have been purchased. You are buying the brand, and it has utility/value because it is the original as per everyone’s understanding. There is an inherent risk associated with the subjective value argument. With cancel culture and politicians changing narratives for personal gains, something can lose its value instantly and arbitrarily.

Basically, something is what it is because we say so. The root of the question then becomes: is it that which is tangible that matters more than that which is intangible? Is love demonstrated by the tangible gifts that are provided or by the intangible emotions that it elicits in the other person? Are you a good parent because you provide for your family or because you spend time with them? I know the correct answer is that it’s both, but reality and utopia are two different things. Some people do not have the luxury of being able to do both, either due to poverty or the lack of it. It is an unfair choice to make but one which is necessitated in the society we live in today.