Introduction

A ship leaves on a long journey, spanning years and continents. Over the course of this journey, every part of the ship, including the crew, is replaced. When the ship finally returns to the first port it left, is it the same ship?

The philosophically savvy will recognize this question as the ship of Theseus, first proposed as a thought experiment thousands of years ago. You can substitute the ship for basically any object, even yourself, and ask: is it still the same?

Dynamic identity

You can rack your brain for ways to justify how the ship is still the same, perhaps play some 4D chess with your philosophical peers. Coincidentally, one proposed solution states objects extend across four dimensions, so persist over time. However, one of the easiest, most comprehensible responses to the question is “no, the ship is not the same.”

To use the ship as a conceptual anchor, as the ship gets replaced, its identity gradually changes. Similarly, as parts of you (you could say your cells) get replaced, you gradually change.

Conclusion

Accepting this perspective has some interesting consequences. Even if you were this way in the past, you are not necessarily that way now. To extend morally, if you were good¹ in the past, you are not necessarily good now. If you were bad in the past, you can be good now.