Every
ten years each of us becomes Theseus' ship, or a ship of sorts. Allow
me to clarify what I mean by this. Legend has it that the famous ship
sailed by the hero Theseus was kept in a dry dock, prefiguring what
we do with some museum pieces, for all to behold the vessel that had
enabled so many feats of prowess. Plutarch wrote in this piece
(nicely translated by John Dryden) that as some of the ship's planks
started to rot they were replaced, and that year after year all of
the original planks had been replaced so that it was logical for some
to contend the very existence of Theseus' ship. If no original piece
remains, it can't be the same ship, can it?
To
cut a very long story short, the issue has been debated up until now,
and is likely to remain so for a long time. It didn't help that
Thomas Hobbes introduced a spin-off to the story (in De
Corpore,
1655): the Athenians who replaced
the rotten planks didn't have the heart to throw them away, but kept
them in a dry place for future generations to manage. Imagine now
that these future generations repaired the rotten planks and
reassembled the ship to its original form. Which one would be the
“real” ship of Theseus?
You
might have seen me coming by now: it's sort of the same thing with
us. It is now common knowledge that many, many cells in our body have
a life span, that they die and are replaced in a continuous cycle. In
just a few days our intestines will have renewed themselves
completely. Taste buds in ten to fifteen days. It takes two weeks to
a month for our body to renew its skin cells entirely. Same for our
lungs. Liver cells renew in a few months (four or so). Every three to
six years not a single hair on our head is the same. Bones take a
decade to regenerate, while studies show that the stem cells in the
heart are replaced over the course of twenty years or so.
So...are
we still the same? If our entire body is completely renewed in the
course of ten years, we can't really be the same “us”, can we? A
person aged eighty will have shed its body eight times over, like a
spider shedding its casing so it can grow. Those who are keen to
question the ontological paradox cannot ignore that this comes with
some caveats: only the cornea in your eyes renews its cells, the rest
of the eye is the “same” age as you are. The brain doesn't renew
anything during its lifespan – which therefore corresponds to your
lifetime. So it must be something else.
Heraclitus proposes to answer this by taking the analogy of the
river: if you step in a river one day, and you step in the same river
many years later, neither the river nor yourself will be the same.
The drops of water will have been long gone into the sea, and you
will have experienced events which will have changed you. The key
here is experience: life events change our frame of mind, our
perspective and outlook on life, death and other matters. In a way,
we're never ourselves entirely and fully as we
constantly change.
So...no
self, ever? As per usual, it's a tad more complex: our identities may
change and shift over time, our bodies may not entirely be the same
as our cells renew themselves, as we acquire scars. Epigenesis
postulates that even though the DNA sequence is the same in every
cell, our genome changes over time, epigenetic markers bearing
witness to the thrives and throes of any individual's life. (Long
aside here: epigenesis is a fascinating subject, I can't recommend
enough that you research it for yourself...and initially I didn't
want to give any pointer as I didn't want to influence anyone on this
particularly hot topic, but as it's a vast and complex issue I could
recommend reading this article,
perhaps this one too
which is less technical, and researching Lamarck, Weissmann, and
Lyssenko.) In a nutshell, all the environmental changes around you
which influence in one way or another your way of living, or your
diet, or the need to be warm or look for colder climes etc. will
leave a chemical mark in your genome, to be passed on – or not –
to future generations.
Hang
on, so now you're telling us that every ten years we're different all
over? Well, no. Schrödinger and
Heisenberg would probably frown at this, and each for different
reasons, but it is theoretically possible for an object to be in two
states, or for this object's state to be indeterminable, at
the same time. The ship could be in two
locations at the same time because if A = B and B = C then A= C, or
nowhere at the same time because the ship doesn't matter, as A ≠ B and B ≠
C then A ≠ C (ergo,
there is no ship). The key question here is: is reality dependent on
the observer, or is it true at any time and place, regardless of
whether or not people measure and attribute meaning to the thing
observed? If you change every single member of your favourite
football team, is it still the same team you're supporting year in
and year out? That's because we attribute more internal “meaning”
than what science tells us there initially is (actually science tells
us that there can be no internal meaning as there might be no
external meaning).
Chomsky
would probably agree that our definition of “the same” is screwed
because our outlook is skewed. The two ships, our bodies (rather, the
different aspects of our body over time), are qualitatively
identical, not numerically so. He would also gloss that we, poor
human beings with limited senses and perception, externalise some of
what we believe to be ontologically true onto the physical world. Our
gut feeling (aka intuition) tells us this or that ought to be true
but cognitively speaking we're mistaken. Same goes with Theseus' ship
exemplifying our double standards. Imagine the ship in a museum: the
whole ship is labelled “Original Ship of Theseus”, parts are
labelled “Original bed”, “Original linen”, “Original
rudder”. Some planks have been replaced: still the same ship. Most
planks have been replaced: same ship. All of them: same ship. Rudder
need be replaced: well, not original rudder any more...fake news!
Changed linen: change the label! Do parts compose the whole? Is the
whole whole even if it's no longer whole?
Perhaps the conundrum should be put differently, within a tighter set of boundaries. Being or remaining the same or different remains a valid line of questioning if we pluralise our approaches and don't consider one set of variables to be the only one worth examining. For our
brains will tell us different things at different times. It might
tell us that the original ship is waiting to be reassembled, and we
will have to use the same elements, down to the same nails. But even
if we use the same techniques as back then, would your brain tell you
it's (finally!) the real
ship of Theseus? How could we know? What if Theseus' crew had to
change parts of the “original” ship while on board? Do we have to
redefine 'original' even after every repair? Do we have to question
and redefine our selves every ten years? Every other month? Is
identity an ever-shifting concept, never to be grasped? What is
right: our senses, our intuition, natural sciences, philosophy,
quantum theory?
I'll
leave you with one such theory: would it be utterly nonsensical to
figure ourselves one object at a particular point of space and time,
and then agree that this is “me” or “Theseus' ship”, and then
agree further that this “me” is also “me” at a different
point in space and time, and that these “mes” are just multiple
covariants of “me”? Part and parcel of the same equation? A set
of coordinates doesn't mean
anything per se,
and differentials can only acquire meaning if the frame of reference
remains within the bounds of what we designate as 'reality'.
The
answer, if there needs to be any, follows the same differential path:
it shifts according to the tools with which its components are
examined, and possibly lies in more than one frame of reference.
