98% of your atoms are replaced
every year.
Your body makes 330 billion new cells a day. By the end of ten years, most of your body has been replaced — entirely new matter, running the same pattern. The chemistry changed. You didn't.
"More fundamentally you are not matter. You are information that makes matter."
— Jed Anderson
If you are a pattern, not a substrate — then the question of what makes you you is not a chemistry question. It is a deeper question entirely.
"What lies at the heart of every living thing is not a fire, not warm breath, not a spark of life — it is information." — Richard Dawkins