If Every Neuron Is Replaced, Are You Still You?

Micro-reflection on a Slovakian cathedral and the Ship of Theseus

The following is a first for me — sharing a LinkedIn post as a Substack entry. I would love to expand it into a longer essay at some point. For now, consider this an abridged meditation on medieval architecture, neurons, and the essence of self.

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Visiting Slovakia (and the top of the cathedral where my ancestors worshipped!) really made me think about a paradox in neurotech…

If every brick in St. Elizabeth’s Cathedral were replaced, would it still be the same building? The original Gothic structure was destroyed by a fire in 1380, then reconstructed. And yet after numerous restorations, we still call it by the same name.

It’s a classic Ship of Theseus exercise… And it reminded me of a thought experiment that used to keep me up in college:

If each neuron in your brain were replaced with an artificial one, at what point would you stop being YOU? (Honestly, I just can’t seem to reach a conclusion yet… if you have ideas, I’m all ears).

Questions about essence and personhood feel more urgent now than ever. As Rebecca Lowe argues well, the Age of AI truly is the Age of Philosophy!

So perhaps our best path forward as we navigate neurotech is to:
(1) reflect with intention, and
(2) avail ourselves to some framework greater than ourselves/our own ambition

— just as my ancestors did when they stood in this space.

What do you think — where do we draw the line between where the human ends and the machine begins?