Cycle and recycle

I heard a story once a long time ago that over time all the cells in our body die off, and are replaced by new cells. The entire process, it is said, takes seven years.

I googled this fact this morning and it turns out to be totally a myth, up there with “we only use 10% of our brains” for dubious quasi-biological “facts.” But that’s the dubious quasi-biological fact I’m hanging my theme on here and I’m going to stick with it. Bear with me.

Greek legend tells of the story of Theseus’ ship, which was preserved for hundreds of years in port after the founding of Athens. When individual boards in the ship broke or rotted away, they were replaced, until finally none of the original ship remained.

There’s a similar old story of Grandfather’s axe you may have heard: grandfather’s axe has been handed down from father to son for generations. The handle has been replaced four times, the axe head twice.

The paradox for philosophers, then, is whether Theseus’s ship or Grandfather’s axe actually still exists. Is it still the same object if every component of it has been replaced with some other component?

If we turn over all the cells in our body every seven years, are we still the same person?

This paradox also makes me think me of Doctor Who (OK, seriously, bear with me), in which the titular character dies and regenerates on a regular basis, with each incarnation having all the memories of the original but a different appearance, personality, and outlook. (It’s an awfully convenient plot device for a long-running character whose actor must be replaced once in a while).

If we turn over all the cells in our body every seven years, are we all just Theseus’ ship, grandfather’s axe, slow versions of the Doctor: at our essential root the same person, but continually changing into new versions of ourselves?

I bring this up because today is my birthday. My fiftieth birthday. Fifty is a big number, a round number, a half a century, a significant birthday by any measure. I could grimace and grumble and whine about that. Or I could point out as I turn 50 I have completed seven cycles of seven years. Like the Doctor I am just beginning my eighth regeneration.

In past cycles I have been a redhead, a drummer, a geek, a writer, a goth, a drunk, a recluse, and a lunatic.

I am super curious to see where this season’s plotline goes.

(Header photo from grixti on flickr (original; CC BY-NC-ND 2.0)