Is there an afterlife? Can a computer be conscious? In Part 1, I pointed out that the popular science answers to these questions depend on the assumption that the brain causes consciousness. In Part 2, I introduced two statements which, if taken together, imply that the brain does not cause consciousness. I then explained why Statement 1 is true. The two statements are:
1) A brain can be copied.
2) A person’s conscious state cannot be copied.
In today’s post, I’ll address Statement 2. This statement is definitely more difficult to prove, which is why it’s so revolutionary. The clearest explanation, I think, is this 23-minute video that I presented at the 2020 Science of Consciousness conference. (There is also a more thorough video explanation here.) The most detailed and precise explanation is in my paper. But since my goal in this blog post series is to explain things to a lay audience without all the fancy bullshit, this post will (I hope) convince you of Statement 2 with a simpler explanation.
To convince you of Statement 2, I’ll start by assuming the opposite, and then show how it leads to a problem or contradiction. So let’s assume that you’re in some conscious state that can be copied. Let’s call that conscious state C1. Since it can be copied, and we live in a physical world, there must be some underlying physical state that we can copy. Maybe that physical state is the positions of all the atoms in your brain. We don't have to know exactly what that physical state is -- the point is that there is some physical state that can be copied. Let’s call that physical state S1.
Let’s be clear. You are experiencing conscious state C1. And that conscious state is entirely created by physical state S1. So if we were to copy that state S1, and then recreate it somewhere else, then that copy of S1 would produce your conscious state C1. That’s the whole point of the assumption. If you are experiencing state C1, and we recreate state C1 on a distant planet in the Wazoo Galaxy (by copying the underlying physical state S1), then you would experience state C1 on that distant planet.
Now, let’s say we make a copy of physical state S1 (which produces your experience of conscious state C1). We then recreate it on Mars (preferably in a habitable station), and then simultaneously kill you on Earth. There’s no problem, right? You would just experience being on Earth in one moment and then on Mars in the next. It would just feel like you were teleported to Mars.
But what if we also recreate physical state S1 (which produces your experience of conscious state C1) on Venus? What would you experience if there were two versions of you, both experiencing conscious state C1 created by underlying physical state S1?
More specifically, what would you experience the moment after that? Being alive on Mars and Venus would be vastly different experiences. Let’s say that on Mars, your physical state S1 would change to S2M (which creates conscious state C2M), while on Venus, your physical state S1 would change to S2V (which creates conscious state C2V). State C2M might be the conscious experience of looking out at a vast orange desert, while state C2V might be the conscious experience of looking out at a dark, cloudy, lava-scorched land. I don’t know exactly what it would feel like, but certainly the two conscious states would differ.
Which conscious state would you experience, C2M or C2V? There are only three possibilities:
· One or the other
Before proceeding, I should mention something important about physics: locality. Generally speaking, you can only affect, or be affected by, things that are nearby (or “local”). If you’re at a baseball game and worried about getting hit in the head with a fly ball, sit far away from home plate. That way, you’ll have plenty of time to move if a fly ball is heading your way. Even though the idea is simple, it’s an extremely important and fundamental feature of the physical world. Einstein is famous for formalizing the concept of locality in his Special Theory of Relativity, which asserts that nothing, including information, can travel faster than the speed of light.
The speed of light is very fast (186,282 miles per second), but it is still finite. Nothing that happens in a distant galaxy can immediately affect you, because it takes time for information of that event to reach you. In fact, our own sun is about 8 light-minutes away, which means that if it exploded, it would not affect us for another eight minutes. The only known violation of locality is quantum entanglement, but even quantum entanglement does not allow information or matter to be transmitted faster than light.
Getting back to the above example, when we recreate physical states S1 on Mars and Venus, those states are not local to each other, which means they can’t affect each other. And Mars and Venus are far enough apart that subsequent physical states (S2M on Mars and S2V on Venus) also can’t affect each other.
We already know that when we create state S1 on Mars (and kill you on Earth), you would experience being on Earth in one moment and then on Mars in the next, as if you teleported to Mars. Your subsequent conscious states (C2M, C3M, C4M, and so forth) would change according to what you experienced on Mars.
And if we had instead created state S1 on Venus (but not on Mars), you would experience being on Earth in one moment and then on Venus in the next, as if you teleported to Venus. Your subsequent conscious states (C2V, C3V, C4V, and so forth) would change according to what you experienced on Venus.
So what would happen if we create state S1 (which produces conscious state C1) on Mars and on Venus? Which conscious state will you next experience, C2M or C2V? As I said before, there are only three possibilities, which I’ll analyze below:
· One or the other
Neither. Maybe it’s neither. Maybe the universe doesn’t like it when we create multiple copies of a conscious state, so when you create two or more copies, they both get blocked or eliminated or something. Here’s the problem. When you are created on Mars, your conscious state cannot be affected by what is happening on Venus because the two events are nonlocal. There is no way for your physical state S1 on Mars to “know” that state S1 was also created on Venus because it takes time for information to travel from Venus to Mars, even if that information is traveling at the speed of light. Your physical state S1 will change to S2M (which produces your conscious state C2M) long before a signal can be sent to stop it. Therefore, you will experience conscious state C2M, so the correct answer cannot be “neither.”
Both. Maybe you will experience both conscious states C2M and C2V. I certainly have no idea what it’s like to experience two different conscious states at (what I would perceive as) the same time. Nevertheless, maybe it’s possible. But here’s the problem. Your conscious experience of C2M is created by physical state S2M, which is affected by stuff on Mars, while your conscious experience of C2V is created by physical state S2V, which is affected by stuff on Venus. For example, if state C2M is your experience of looking out at a vast orange desert, it’s because light rays bouncing off Martian dunes interacted with your physical state S1 to produce S2M. But information about that interaction is inaccessible to whomever is experiencing state C2V on Venus, once again because information does not travel fast enough between the two planets. Therefore, whoever is experiencing state C2V on Venus cannot also be experiencing state C2M on Mars. Therefore, maybe you’re experiencing state C2M or C2V, but you can’t be experiencing both.
One or the other. The correct answer to the above question is not “neither” and it’s not “both.” The only remaining option is that you experience either C2M or C2V. But which one? How could nature choose? Maybe you experience the “first” one created. The problem here is, once again, nonlocality. Let’s say that, according to my clock on Earth, state S1 is created on Mars at 12:00:00pm, and state S1 is created on Venus at 12:00:01pm – in other words, one second later by my clock. The problem is that there is no way for state S1 on Venus to “know” about the creation of state S1 on Mars (and to then prevent your conscious experience of state C2V on Venus), because it takes much longer than one second for information to travel between the two planets. Therefore, the universe cannot “choose” between C2M or C2V based on time. And because state S1 on Mars is physically identical to state S1 on Venus, there is no other physical means by which the universe can choose one over the other. If S1 changes to S2M (which produces C2M) on Mars and S1 changes to S2V (which produces C2V) on Venus, there is no known physical means for the universe to somehow decide that you will experience only C2M or C2V (but not both). Therefore, you cannot experience just one or the other.
We have ruled out all three possibilities. What does this mean? It means that the original assumption – that a person’s conscious state can be copied – is wrong. Think about the logic this way:
i. If statement A is true, then either B or C or D must be true.
ii. But B, C, and D are all false.
iii. Therefore, statement A must be false.
In this case, statement A is “a person’s conscious state can be copied” and statements B, C, and D correspond to “neither,” “both,” and “one or the other,” like this:
i. If a person’s conscious state can be copied, then we can put copies on Mars and Venus. Either the person will experience neither copy, or will experience both copies, or will experience one or the other.
ii. I showed that none of these are possible (because they conflict with special relativity).
iii. Therefore, a person’s conscious state cannot be copied.
If you recall, this conclusion is the same as Statement 2 at the beginning of this post:
1) A brain can be copied.
2) A person’s conscious state cannot be copied.
If I have convinced you of Statement 2 in this post, and of Statement 1 in the previous post, then what do they imply? This is what they imply:
If a brain can be copied, but a conscious state cannot, then the brain cannot create consciousness.
Certainly the brain can affect consciousness. If someone sticks electrodes in my brain, I have no doubt that it will probably affect my conscious experience. But consciousness cannot be produced entirely by the brain. In other words, conscious experience must depend on stuff (events and states) beyond the skull.
This conclusion should be shocking, but taken seriously, by anyone who wants to understand and scientifically study consciousness. Its implications are significant. For example, getting back to the big-picture questions posed in Part 1, can a computer be conscious? A digital computer has a state that can be easily copied. If it didn’t, we wouldn’t be able to copy files, buy software, or even run software. But as I proved above, a person’s conscious state cannot be copied. Therefore, a person’s conscious state cannot be embedded or executed on a digital computer, because if it could, then the person’s conscious state could be easily copied. A digital computer cannot be conscious because conscious states cannot be copied. Also, mind uploading is impossible because if a computer can’t be conscious, then there’s no way to upload or simulate a conscious mind on a computer. Also, consciousness cannot be algorithmic. An algorithm is a set of instructions that can be executed on any general purpose computer. Once again, an algorithm can be easily copied but a person’s conscious state can’t, so consciousness cannot be algorithmic.
And what about the other question posed in Part 1: Is there an afterlife? Well, my arguments here certainly don’t prove that consciousness continues after brain death. However, the strongest (and perhaps only) scientific argument against an afterlife depends on the assumption that the brain causes consciousness. But I’ve shown that’s false. Further, I’ve shown that consciousness transcends the brain, at least to some degree. The fact that what we consciously perceive is produced by something beyond our brains is at least circumstantial evidence that the existence of consciousness does not necessarily depend on whether a brain is alive.
The brain does not cause consciousness. Much of what science tells us about consciousness, to the extent that it relies on an invalid assumption, is likely false.
 If physical state S1 wasn’t sufficient to produce a conscious state of YOU – in other words, if physical state S1 is inadequate to produce your conscious identity – then consciousness must be produced in part by something nonphysical. And that would be a real problem for scientists!
 If you weren’t also killed on Earth, this would be the “teleportation problem” that Nobel Prize winner Roger Penrose discusses in The Emperor’s New Mind.
 To use physics language, the creation of states S1 on Mars and Venus (and their subsequent evolutions to S2M and S2V, respectively) are spacelike separated events. The argument I’m making here applies equally to timelike separated events, which I discuss in my paper.
 In fact, there is no such thing as “simultaneous” events when we are talking about spacelike separated events. Even though my clock may say that S1 was created on Mars first, the clock of another observer may say that S1 was created on Venus first. There is no objective fact about which event occurs first if the events are spacelike separated.
 Maybe this argument doesn’t apply to quantum computers. However, as I’ve explained repeatedly, a quantum computer sufficiently large to create anything we might regard as intelligent is just as physically impossible as producing Schrodinger’s Cat or Wigner’s Friend.