I'm taking philosophy as a senior subject in high school, so my depth of understanding of pretty much any philosophical theory is very limited. I think I side more with a physicalist account of the mind, believing AI can one day be persons, and a few other things that point me that way, but reading about Derek Parfit's account of the 'teletransportion paradox', pasted from his Wikipedia article below, I'm doubting this a bit.

In Divided Minds and the Nature of Persons (1987), Parfit asks the reader to imagine entering a "teletransporter", a machine that puts you to sleep, records your molecular composition, breaking you down into atoms, and relaying it to Mars at the speed of light. On Mars, another machine re-creates you (from local stores of carbon, hydrogen, and so on), each atom in exactly the same relative position. Parfit poses the question of whether or not the teletransporter is a method of travel—is the person on Mars the same person as the person who entered the teletransporter on Earth? Certainly, when waking up on Mars, you would feel like being you, you would remember entering the teletransporter in order to travel to Mars, you would even feel the cut on your upper lip from shaving this morning.

When reading this, I'm sure that there is more to consciousness that can be copied over by the teleporter. From what I understand, this should imply I lean towards dualism (does thinking there's something more here mean I believe in a soul?), but when searching about the relationship between this experiment and the Mind-body problem, I find very little, leading me to believe I have misunderstood this conclusion.

  • I asked a similar question philosophy.stackexchange.com/questions/82255/…. and Parfit came up in the replies, might be helpful to you. I was assuming a physicalist view too. Hopefully there are more answers because I too am curious.
    – J Kusin
    Aug 1 at 15:41
  • Just ran across this today, you might find it of interest. "Why Artificial Intelligence Isn't Intelligent." wsj.com/articles/…
    – user4894
    Aug 1 at 21:20
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    My 2¢: If you're going at the speed of light, then all observers in all reference frames agree that there is a nonzero period of time for which you "don't exist" (because dematerialization happens before materialization). So the paradox is reduced to "is death in principle reversible?", which may still be interesting, but is an entirely different question altogether, and doesn't pose nearly the same set of problems for physicalists IMHO. If you try to "fix" this by positing that materialization and dematerialization are simultaneous, then you run into issues with relativity and causality.
    – Kevin
    Aug 2 at 23:26

"Can you think a teleporter kills the 'real' you, and also be a physicalist?"

If the description you provided of Parfit's thought experiment is accurate, then the answer is, 'Yes'.

You said, "On Mars, another machine re-creates you (from local stores of carbon, hydrogen, and so on), each atom in exactly the same relative position".

This version of the experiment explicitly states that it the new 'you' is composed not of the original atoms, but of new atoms obtained from local stores.

It is quite possible that atoms have unique physical traits that remain undiscovered and that the new, locally-sourced atoms would therefore give rise to a new - physicalism-compatible - consciousness, even when assembled in an identical way to your original form.

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    You can think that the atoms have unique physical traits that remain undiscovered and give rise to a unique consciousness... but there's no scientific reason to think that. You aren't really a "physicalist" if your philosophy depends on stuff that physics has not found evidence for. You might as well just believe in ghosts and souls - physics hasn't found evidence for those either. Plus, we gain and lose atoms all the time. Over a few years most of the atoms in your body get replaced.
    – causative
    Aug 21 at 23:16
  • Good point. Maybe the OP can deselect this answer. Aug 22 at 4:03
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    @causative But we also know the local physical facts do not tell you the whole facts determinable, see quantum entanglement/nonlocality. And there are unique physical facts in several senses: 1) No two events in spacetime are ever the same 2) A fundamental particle may be unique in how it is entangled, from all other "identical" particles of its type. And we can't even tell by doing purely local experiments. I feel you've unjustly compared Futilitarian's opinion to ghosts.
    – J Kusin
    Aug 22 at 16:32

If your intuition in this thought experiment is that the person that comes out on Mars is not the same person as the one who entered the teletransporter on Earth, then you have non-physicalist intuitions. Many self-proclaimed physicalists still have many residual non-physicalist intuitions, because the legacy of Cartesian dualism runs deep. Dan Dennett explores and deconstructs these residual non-physicalist intuitions in detail in Consciousness Explained. I know you probably don't have time to read that since you already have your assigned readings to keep up with, but if you do find time some day and have interest in that, I highly recommend that book for coming to grips with a full-fledged physicalist view of consciousness.


I would like to raise a couple of points that have only come up tangentially so far.

The first is that if teleportation as described here is actually achieved, with a conscious entity being created by assembling atoms according to a set of instructions, then a certain, common notion of materialism - that, in the natural world, physical processes are sufficient to create conscious minds - would be confirmed, regardless of whether you regard this person to be a continuing instantiation of the original, or a copy.

Secondly, there is a Ship of Theseus issue here: a person is constantly changing the atoms which compose her body, to the point where, after a few months or years, almost nothing of her previous makeup remains, yet this is no impediment to us regarding her as one specific entity throughout her life. The teleportation case goes a step beyond, as there is an intermediate state in which the person is in the form of information encoded in electromagnetic waves rather than atoms (or if stored on a disk, as patterns of magnetization, for example.) Is a replica of Theseus's ship built from plans the same thing as the original? In a comment, @Armand makes the cogent point that if the original still existed, we would have no problem regarding the second instantiation as being a copy.

This also raises the question of whether this information, when realized in these forms, is itself conscious. I would say it is clearly not, as it cannot undergo any sort of activity, including conscious activity, while in that form, any more than can the plan of a ship transport you across the sea - though a panpsychist might disagree (over the consciousness issue, not the analogy to ship-plans-as-vehicles!)

One further thing to consider is the no-cloning theorem, which shows that perfect copies of physical state cannot be made. What is required here, however, is slightly different: the goal is to construct something that will live and think as if it were the original person transported to Mars. If, as seems plausible (at least to some physicalists, though not Penrose), the classical approximation to quantum mechanics is sufficient to realize conscious minds, the no-cloning theorem would not be an obstacle to this sort of teleportation, but I suppose it might be used to argue that the person on Mars is neither a copy nor the original person!

Any talk of teleportation is currently in the realm of thought experiments. As Scott Aaronson has pointed out in several places, these thought experiments are useful in testing our ideas of identity and ethics, much more so than as the basis for another round of the tired old argument over physicalism, which is not going to be settled without more facts.

After all that, my answer to the question comes back to my first point: given the premise of the question, that this form of teleportation is possible, it would be irrational not to be a physicalist in the sense given there. This would not resolve the question of whether the original person has been killed, showing that to be an orthogonal issue, and quite possibly a subjective one.


Consciousness is emerging from neural firings. What makes every consciousness individual and specific is the sequence of neural firings which makes information processing unique for that specific brain.

While consciousness feels like continuum, it exists only in these individual neural firings, and not in between firings or outside the firings. There are millions of neural firings each second, so we don't perceive consciousness as an emergent entity, composed of many individual conscious moments (sequence of brain activity firings).

Therefore, teleported person has nothing in common with original person, except memory. Sequence of neural firings is certainly completely different on Martian copy then on original person's brain, these are now two different consciousnesses.

More interesting question would be, if the brain is reconstructed on the identical planet, and continues to have exactly same neural firings, as original brain. In that case, I argue, both brains will share same consciousnesses, as long as neural firings are exactly identical.

  • Maybe I misunderstood, but are you saying that identity is tied to our instantaneous state of our 'neural firings'? So even without the teleporter, me in one second has completely different neural firings as me in another, so I'm not the same person as I was one second ago? And furthermore, for your final paragraph, wouldn't our mind have to be completely independent of physical input for neural firings to be identical between planets? I honestly don't understand your points very much, sorry.
    – Matt
    Aug 22 at 4:35
  • Yes, you understood it correctly, our perceived continuous consciousness is emergent phenomenon, emerging from sequence of neural firings. As for last paragraph, Since our brain activity is computation, therefore mathematical object, same consciousness emerge from multiple identical brains (identical neural activity). If we assume opposite is true, and two independent consciousness emerge from identical neural activity, then we get to logical paradoxes, like, if we gradually interchange atoms of both brains, at some "magical" moment, both consciousnesses would swap. Aug 22 at 10:43

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