“Schrödinger’s Cat” is a well known thought experiment. It describes a scenario in which a cat in a sealed box is simultaneously both dead and alive, until the box is opened, and the cat observed. Such a situation, where a hypothesis is tested through contemplation, and a solution is arrived at, is called a thought experiment. The replacement argument is one such experiment, which asks if a being retains its own identity if all its constituents are replaced. It is more commonly known as The Ship of Theseus paradox, after Theseus, the founder of Athens. According to legend, a memorial was dedicated in his honor by preserving his ship in port. Gradually, the wooden planks on the ship rotted away and were replaced with new ones of the same material. The question thus arose – if one by one, all of the planks were replaced, was the ship still the same Ship of Theseus?

This could lead to several other questions. What if the wooden planks were replaced by modern metallic ones and the ship came to be of a different material altogether? What if so many changes were made that the ship could no longer perform its original function? Does it remain the Ship of Theseus if it could no longer sail? A more relatable example – every seven years or so, all cells in our bodies die and are replaced. We are, strictly speaking, not the same individuals we were seven years ago. While it might be said that we retain our identities (since our non-material aspects, such as ideas and beliefs, don’t get replaced), could this argument also serve to avoid being accountable for one’s past actions – as if they were committed by a different person altogether?