with teleportation, in particular the concern that when a transporter dismantles the atoms

in your body and reassembles an identical arrangement of atoms somewhere else, perhaps

the disassembled you actually dies and the reassembled you is actually a new being that

just thinks it's you.

And if they simply hadn't dismantled the original you, then there'd now be two “you's”

in the universe, and which is really you?

You, or the teleported you?

Grey's video covers these questions really well so if you want more background you should

go watch that, but I do have one additional piece of information I'd like to point out,

something the original creators of Star Trek were definitely unaware of because it was

discovered in the 90s.

And that, is quantum teleportation.

Quantum teleportation is the only kind of real teleportation technology we currently

have access to, and while I won't go into the details here the point is you can take

some particles in a particular arrangement, and transfer their exact quantum condition

onto other particles arbitrarily far away.

You might think of it as “sad teleportation” because the particles don't move, just their

state – but isn't that essentially what a Star-Trek teleporter does, albeit on a larger

scale?

Sending enough information and energy over to the new location to create the exact arrangement,

or state, of particles that corresponds to “you”?

And quantum teleportation has one pivotal property: it is impossible to create an identical

copy of a quantum state without destroying the original – in fact, you HAVE to destroy

the original arrangement in order to extract all the necessary information from it to construct

the new, teleported, state.

In fact, the relevant theorem in quantum mechanics is called the “no cloning” theorem.

Now, we don't yet know exactly how brains work to create consciousness, but if the quantum

states of some electrons somewhere in the brain are critical to perfectly determining

(and thus copying) “you”, then a teleporter would necessarily have to obey the rules of

quantum teleportation when sending the information about the arrangement of particles that are

“you” to the new location, and whatever was left behind would definitively *not* be

you.