The Ship of Thesus
The Ship of Thesus– -Writing Reflection-1 Heraclitus of Ephesus wanted to identify a single principle that could unify the investigation of all subject matter. He said, “It is not possible to not step into the same river twice.” And claimed that change is the only constant. With that in mind, one might suspect anything and everything that might not change over time. Most of us will agree that physical aspects of plants, animals, food, babies, human beings and our identities change over time. But what about objects? Does a car change over time? How about jewelry, clothes, shoes, trains or a ship? Even though we might think they do not but The Ship of Thesus is a philosophical puzzle that touches upon two major identity theories; namely, the Mereological theory of Identity and the Spatio-temporal theory of Identity that demonstrate how an object might change over time.
The puzzle revolves around Thesus, a hero of Athens who killed the Labyrinth and returned from Crete, ending the sacrifice of Athenian people. As a celebration, every year the same ship took the same route to Crete and back to Athens. However, since the ship got old over the years, it needed repairing; its parts were replaced with new ones, one at a time. So, the question arises, is it really the same ship that Thesus made history on? To analyze on a deeper level, let’s take Thesus to be on the old Ship ‘A’ in Crete and as he travels to Athens he repairs and discards the old parts along the way. However, he has repaired and replaced every single part of the ship while discarding the old parts in the sea and ends up in Ship ‘B’ by the time he reaches Athens. According to the Mereological theory of identity, for an object to be the same it must have all the exact same material at the core of its atom; the identical appearance is not enough for an object to be the same. Hence, even though ship B looks identical to ship A, even though Thesus never got off the ship and maybe did not replace all the parts of the ship, yet they are not the same ship as each repair made to the ship means that it’s a different or a new ship.
Furthermore, according to the spatio-temporal theory of identity, an object must exist from moment to moment and trace a continuous path, that is, there must not be a broken path (one cannot dismantle an object at point A and reassemble the parts at point B), or you cannot teleport an object from one place to another. Hence, even though Thesus replaced and discarded the parts of the ship in the ocean, he travelled through the distance and continued to exist from moment to moment (he did not teleport or stop existing), one can track the ship’s path and so Thesus’s ship A is the same as Ship B.
A more complex version of analyzing the puzzle is: As Thesus traveled from Crete to Athens while discarding the old parts of the ship in the sea, he is trailed by a small boat carrying Al Gore- a politician and an advocate of climate change, who gets frustrated by Thesus’s actions of littering the ocean. He collects the discarded parts and starts rebuilding the ship in the exact same manner as it originally was.
Hence, by the time Thesus reaches Athens, Al Gore is travelling in a ship that is not only made up of the original parts of the ship A, looks similar to that of Thesus’s new repaired ship but it is also the original Ship A that Thesus started his journey on, according to the Mereological theory. However, if we analyze the scene according to the spatio-temporal theory, Al Gore never got the same ship as he never travelled a continuous path from moment to moment but rather reassembled one part at a time and came with a ship by the time he reached Athens. According to me, Al Gore got the ship. Identity for objects cannot be the same as that of human beings as objects are non-living things they can exist for eternity without interference, but human beings must die after a certain time with or without interference. Yet their identities can be similar to some extent. For instance, S is a girl. Human beings are said to be completely new people after 7 years as we replace each part of our body, according to mereological theory but that still makes S the same girl. S cannot be dismantled and reassembled completely (can be partially: if we use a prosthetic in place of a leg that still makes S the same human being) but objects can. Yet S will always be the same girl who is born on the same day and year, she is still the same age. Similarly, even though the parts of the ship were dismantled and reassembled to a ship, the ship will always remain x years old. According to this approach, Al Gore gets ship A!
According to me, for an object to continue to exist as the same object over time its age must be taken into consideration. I look at it in comparison to human beings. I have undergone many changes since childhood; however, I continue to exist as the same person that was born 21 years ago irrespective of the body or identity changes. Similarly, in the case of objects- if I buy a table in its dismantled form, it has continued to exist from the moment its parts were made. Spatio-temporal theory seems to be more closely related to my view on identity as the parts of an object matter less than the existence of an object.
In conclusion, the puzzle of the ship of Theseus is still a puzzle especially in its complex form as it is not possible to comprehend each aspect of the puzzle without compromising something of the other. My own answers are questionable; however, to arrive at a conclusion, one must incline to one side of the puzzle. Lastly, as convinced as I was with Heraclitus’s claim that the only constant is change, it brings about some serious metaphysical questions and identity of objects.
The Ship of Thesus – Scenario 2
Srishti Saini
PHIL-1A -The Ship of Thesus-Writing Reflection-1
June 26, 2024 https://globalbuzznetwork.com/the-apology-written-reflection-2/
The Ship of Thesus – https://www.philosophy-foundation.org/enquiries/view/the-ship-of-theseus