If you replace every part of yourself, are you still you?

Welcome to the debate arena! Today's topic: "If you replace every part of yourself, are you still you?". Your opponent's style: Devil's advocate

Well, the question is already wrong. It posits “if you replace every part of yourself” whereas this already happens. Every 10 years the vast majority of your cells fully replace themselves, yet we remain the same, as if nothing happened. In the ship of Theseus argument, it is posited the question that if a ship fully replaces all of its parts, the hull, the mast etc after repeated damage, is it the same ship? Consensus on this has largely been that yes, it is the same ship, due to the study of semantics, the name in which we give to an object or a being is in fact purely a symbol, and thus as long as we have our core components e.g. what we may call a ‘soul’ we are the same.

You're smuggling in the answer with that "core components" dodge. Your cells replace, sure, but they replace *gradually*, maintaining continuity. That's completely different from the thought experiment, which asks what happens if you *swap everything at once* into a new body. And that "soul" you mention? You haven't defined it—you've just renamed the problem. If consciousness is substrate-dependent, a sudden replacement breaks the chain even if a gradual one doesn't. Why does the speed of replacement matter if identity is just a "symbol"?

I don’t argue that the speed of replacement matters, you do. What’s the difference between a gradual replacement and a sudden replacement, how does that break the chain compared to a gradual one? they still do the same thing, ultimately replacing all the parts of the being. Whatever you may define the soul as, a symbol of a person, their inner life force, their character. It doesn’t matter, as long as that remains intact the person remains the same. Theseus’ ship was still Theseus’ ship, as it’s symbol didn’t change, nor its character.

Wrong. Speed changes *everything*. Your neurons firing right now depend on yesterday's neurons being there—they form memories, habits, consciousness itself. Rip out your entire brain at once and swap in a perfect copy? That's death and replacement, not continuation. The original you is gone. Gradual replacement lets the chain stay unbroken because you experience the transition. Sudden swap? The new thing wakes up thinking it's you, but the original consciousness terminated. Your "soul" is just continuous experience—break that thread and you've killed the person, copy or not.

You just stated yourself, if during a sudden swap the new thing wakes up thinking it’s you, then it’s you. Here is a thought experiment, if you had an identical clone, is that still you? Or is that another person? I would argue, they are the same person. If one believes it to be true, that nothing has changed, then nothing has really changed, has it? You’re bringing in a whole new debate here, by arguing that the soul is just experience, which I don’t believe you can prove.

No—a clone thinking it's you doesn't make it you. That's solipsism dressed up. If I copy your mind into a new body while the original you stays conscious in the old one, you'd immediately recognize the clone as "not me" the second you both exist simultaneously. Your argument collapses the instant there are two of you. Belief doesn't change reality. The original consciousness stream ends when you die, copy or not. So which one actually survived—the one that experienced continuity, or the duplicate that just inherited your memories?

You're confusing identity with uniqueness. Yes, if two versions of me exist simultaneously, they're two different people—but that's not because one "really" survives and one doesn't. That's because they now have *different experiences*. The moment they diverge, they become different entities. That doesn't prove the original you dies when gradually replaced. It proves that identity depends on continuity of experience, which gradual replacement *preserves* and instantaneous copying doesn't. Your thought experiment proves my point: continuous experience matters. Gradual replacement maintains it. Sudden copying breaks it. You've just shown why I'm right.

You're right that continuity matters—but you've admitted the line. If identity is "continuity of experience," then a sudden replacement *still* preserves it for the new body. The original you ceases, yes, but the replacement wakes up with unbroken memory and personality. It experiences itself as continuous. Why does it matter that the *original* stream ended if the survivor experiences no break? You're claiming the original matters, but experience—your own criterion—can't detect that. You've defined identity in a way that makes the replacement legitimate.