"Your body completely replaces itself every 7-10 years, so you're literally not who you were"

Your body is constantly regenerating. Different cells have different lifespans, but most are completely replaced within a decade:

Fast Regeneration:

• Stomach lining: 3-5 days
• Skin cells: 2-4 weeks
• Red blood cells: 4 months
• Liver cells: 6 months

Slow Regeneration:

• Fat cells: 8 years
• Bones: 10 years
• Heart muscle: 20 years (partially)

From a purely physical standpoint, the atoms that make up your body today are almost completely different from the atoms that made up your body 10 years ago.

You've literally been rebuilt, atom by atom, like a biological Ship of Theseus.

Not everything regenerates:

• Brain neurons: Most last your entire life (though connections change)
• Eye lens cells: Never replaced
• Heart muscle: Very slowly replaced, if at all

Ironically, the parts that define "you" (your brain) and how you see the world (your eyes) are some of the few parts that DON'T get replaced.

If your body has completely different atoms, are you the same person?

Biologically: No. You're literally made of different stuff.

Legally: Yes. Your identity persists.

Psychologically: Debatable. Memories and personality evolve.

Philosophically: Welcome to the existential crisis zone.

Your body maintains the illusion of continuity through:

• Pattern preservation: Cells replace themselves in the same arrangement
• Memory: Your brain stores experiences (even though the medium changes)
• DNA: Your genetic code remains consistent (mostly)

You're not a static thing—you're a process. A pattern that persists through constant material change.

Good news:

• Got a scar? It'll eventually be made of new cells
• Ate something bad? Those stomach cells will be replaced soon
• Made unhealthy choices? Your body is rebuilding right now

Bad news:

• Tattoos persist because ink lives deeper than cell turnover
• Some damage (like brain injuries) might be permanent
• Radiation exposure affects cells that haven't been born yet

In a very real sense, you ARE a time machine. The "you" from 10 years ago is gone, replaced by current-you. Your past self has died and been reborn multiple times.

Every decade, you're piloting a completely new biological vehicle with the same license plate.

If your body is constantly dying and being reborn, when do "you" actually die?

Are you dying right now, one cell at a time?

Are you being constantly reborn, one cell at a time?

Is death just the moment when the regeneration stops?

You are not your body. You're a pattern, a process, an ongoing story written in constantly changing ink.

The "you" that started reading this is already partially dead. The "you" that finishes reading this will be partially reborn.

You are simultaneously dying and being created, every moment of every day.

Welcome to biology. It's weirder than you thought.