For those of you unfamiliar with Theseus's Ship, it raises the questions: If part of a boat was taken away and replaced, is it still the same boat? What about two parts? What if every part was eventually taken away and replaced by another; is it still the same boat? If not when did the transition occur? What if every part of the boat is taken away and replaced, but we take the old parts and use them to make a new boat. Which is the original? Are they the same boat?
Anyway, this got me thinking.
If all of the cells in our bodies are constantly changing and dying and making new ones, why do we consider ourselves the same person as we were yesterday, or a week ago? We are made up of entirely different (albeit genetically identical) cells than we were (I believe) ten years ago, but why are we considered the same biological organism?
If a river is flowing, how can it stay the same? Every drop of water is somewhere else, taken away, replaced, added, or whatever, so the river is never the same at any given time. The river is constantly changing, and cannot be called the same, yet it is.
Maybe the river is just an illusion. I'm not saying that the river isn't there, but maybe it doesn't exist as we think it does. Rivers exist and are made up of change itself, and not the water that runs through it. The water will disappear, and maybe reappear later, but the constant flow of change is what keeps it the same.
This, of course, applies to Theseus's Ship and to us as humans.
We can't exist as one specific thing, as much as we might try to. Instead, we exist as a sum of our changing. If one part of a boat is replaced, it is still the same boat. As if every part. The new boat made from the old parts is also the same boat; both are just different sums of the same changes. We are the same as we were ten years ago because we are the vessel of change, and the change is constant and defining.
Thoughts?