The Story Of The Ship Of Theseus: The Question Of Identity

We’ve all wondered: Who am I? Identity is a question we all have asked. Many thinkers throughout history have tried to solve this puzzle. Thomas Hobbes (1588) was a British-born philosopher. In an attempt to answer the question, he uses a Greek story. He asks, “what keeps something the SAME, even when it undergoes changes?”

Theseus sails and owns a large ship. Every month, he would sail into a new port to have an old plank replaced by a brand new plank. The ship of Theseus has not one original plank left after 10 years. Theseus does not know that the ship-repairman has saved every plank he takes out of Theseus’ ship. He builds a ship slowly and arranges the planks exactly the same as in Theseus’ original vessel.

Hobbes will then ask, “Which is the number one ship, and original ship of Theseus?” Is this the ship with new parts or a re-constructed version of that ship, with original parts?

Hobbes tries to answer this question by using two principles. The “gradual-replacement principle” states that if an object X consists of many different parts, but a single one is removed, resulting in object Y then X and the Y are identical. Object X & Y must share the exact, same parts, arranged precisely the same. This is the second principle. In light of these two principles, we can conclude that neither principle is true. This would be in violation of the “transitivity” of identity. In contrast, if B=A and A=B then only one ship would exist.

Hobbes stated that the biological changes that occur in a human being over time would result in a change of tissues. Hobbes says that if the person is changing gradually, it’s still them. As a human being cannot live with the same physical body.


  • ernestfarley

    Ernest is a 26-year-old education blogger and teacher who writes about a variety of topics related to teaching and learning. He has a passion for helping others learn and grow, and believes that education should be accessible to everyone. Ernest is a graduate of the University of Texas at Austin, and he has taught high school students in the United States, Mexico, and Chile.