you draw the line?
One of the issues I found interesting to
when I was a
teenager is where do you draw the line in replacing human body parts
with artificial parts?
1) Which piece of you is “you”?
that scientists discover a way of using stem cells to re-create any
portion of our body that is damaged. For example,
if one of
your teeth was damaged, it could be
pulled out, and stem cells could be used to grow a new tooth exactly
like what you already had, using your own DNA.
If your foot was destroyed in an automobile accident, stem
cells could be used to
regrow the foot exactly as it was, using your own DNA. You would not be
able to tell the difference between the original and the replacement,
except that the replacement would not have any scars or other
Assume this technology existed right now. Would you use it
damaged parts on your body?
that you get into a car accident and you need to replace your right
foot. Would you be willing to use stem cells to
replace that foot? I think everybody would do it.
Then imagine an earthquake occurs in
your area, and you lose your left leg. Would you go without that leg?
Or would you use stem cells to replace the missing
imagine that you develop cancer in your stomach. Would you authorize
the doctors to use stem cells to grow a new digestive system for you?
Or would you rather die?
Next imagine that your heart fails. Would you use stem cells to grow a
replacing your parts with new parts, you end up living longer, but as
you live longer, you experience more cancer, and more accidents. The
longer you live, the more of your parts you have to replace.
that you splatter something flammable in your face, and burn your face,
including your eyes. Would you use stem cells to
regrow your eyes and
face? You probably would.
If your pituitary gland was destroyed from cancer, would you use stem
cells to regrow it? You probably would.
this continues for decades. Imagine that
after 150 years
you have replaced every component on your body except for your brain.
This brings me to three issues that I liked to think about when I was
Imagine that your brain
suffered some tremendous damage from cancer or an accident. Would you
use stem cells to regrow your brain? If you did, it would be the same
brain, but it would not have any of your memories. You would become a
adult that didn't know anything. You would have to relearn your
language, how to walk, and even how to see with your eyes. Would you do
it? Or would that be idiotic? Would that be creating a new and
different person? Which component in your body
can be replaced without altering you, and which
component, when it
dies, is the death of you?
2) Would you replace all parts at the same time?
Most of us would choose our brain as being the
component of our body that we regard as "ourself". We would
regard our body as replaceable. Therefore, why not use stem cells to
entire body rather than replace component by component?
3) Would you want a robotic body?
In other words, why not behave like airline mechanics who
replace parts after a certain amount of time wait for them to
fail? Instead of letting your digestive system, muscles, and heart
slowly deteriorate through age, why not follow
a maintenance schedule in which every 20 or so years you use stem cells
to regrow a new, healthy adult body?
Visualize this happening.
Visualize the doctors pulling your brain out of your old body, and
putting it into a new, brainless, 20-year-old body that has just been
stem cells and your own DNA. Would you do that?
If you would replace your components one by one, and if you
are willing to
replace virtually everything in your body, what is the difference
between replacing your body bit by bit, and replacing all of it at one
of today, our ability to produce mechanical arms and legs is crude, but
the people a million years in the future might be able to develop
robotic arms and legs that work better than our
arms or legs. Furthermore, they could design
them for different purposes, such as designing some arms and legs for
strength, others to be lightweight, and others to handle high or low
temperatures. This would allow people to switch their artificial arms
and legs depending on what they wanted to do.
If you are willing
to replace your entire body at one time, why replace it with a living
body? Why not put it into a jar so that it can be protected, and then
connect it through a wireless system to a robotic body? By doing that,
you would be able to choose which robotic body you wanted to control.
For example, if you wanted to fly, you would connect to a drone or
airplane. If you wanted to go into the ocean around Antarctica, you
would switch to a body that can swim in ice water, and which has lights
built into the shoulders so that you don't have to carry lights. If you
wanted to explore Mars, you would switch to a robotic body that can
wander around on Mars without any concern about radiation or
temperature. You could even walk into a volcano to get a closer look,
and it wouldn't matter to you that the robotic body eventually melts.