Is Time Travel Possible? Part 1

Traveling into the Future

We can certainly travel into the future, which is what we are doing right now at the rate of 1 minute per minute.  We can even change that rate.  With drugs or alcohol, we can change the perceived rate in which we travel into the future.  But we can also change the actual rate, relative to others, thanks to Einstein’s relativity.  This is called relativistic time dilation and it is caused by two physical phenomena. 

The first is relative motion (characterized by Einstein’s “special” relativity).  Imagine you and a friend are wearing really accurate and precise watches.  If your friend is moving toward you or away from you at some speed, her watch will tick slower than yours.  However, the effect in our normal everyday world is very, very tiny.  Take the person’s speed, divide it by the speed of light, then square that result, and that’s the approximate effect.

For example, let’s say your friend is jogging toward you at 3 meters per second (which is almost 7 miles per hour).  Divide that by the speed of light (about 300,000,000 meters per second), and then square that result, and you get 10^-16, or 0.0000000000000001.  So for every second your watch ticks, your friend’s watch will tick 100 billionths of a billionth of a second slower.  Imperceptible.  However, if your friend could approach the speed of light relative to you, then her watch would slow down significantly relative to yours.  In fact, if she zoomed away at near the speed of light for long enough, then turned around and returned to Earth, she might have aged only a few months while you aged a few years or longer.

The second phenomenon is gravity (characterized by Einstein’s “general” relativity).  Time slows inside a gravitational potential well.  For example, time ticks slightly slower on the surface of the earth than in outer space, which is why GPS satellites must account for this tiny effect to stay accurate.  The stronger the gravity field, the stronger the time dilation.  A great example was in the movie Interstellar in which the crew lands on a planet closely orbiting a supermassive black hole, leaving one crew member in the mother ship much further from the black hole.  The crew on the planet felt time passing normally, but when they returned to the mother ship, they realized that their hour on the planet had corresponded to many years passing for the crew member on the mother ship.

These things are certainly interesting to think about, but the technology does not exist – and may not ever exist – that will allow humans to experience significant time dilation.  Yes, time dilation is real and we have to account for it in GPS satellites, nuclear reactors, and particle accelerators, but will we ever have the technology to accelerate a human to near the speed of light (relative to another human)?  Probably not.  So while possible in principle, time travel into the future through use of relativistic effects will probably remain science fiction.

Traveling into the Past

The far more interesting question, and the one that most people wonder regarding time travel, is whether it’s possible to travel into the past.  We all want to be Marty McFly (or Doc Brown, depending on your personality), with the freedom to see the past, experience the past, and even change the past.

Lots of reputable physicists, like Nobel Prize winner Kip Thorne (author of Black Holes & Time Warps), claim that the laws of physics allow for time travel into the past, and even suggest fascinating ways of doing so, like stretching open and passing through wormholes.  (Note: wormholes are theoretical predictions and there is exactly zero empirical evidence that they exist.  Even if they could exist, there is no good reason to believe that we could ever create them at will, engineer them to specifications, choose their endpoints in spacetime, stretch them open, or pass matter through them.  They are, purely and simply, science fiction.)

The obvious problem with time travel into the past is the risk of a temporal paradox.  For example, what would happen if you killed your ancestors?  If you did, then you couldn’t be born, which means you couldn’t go back in time to kill your ancestors.  Doesn’t that problem by itself rule out time travel into the past? 

Some say that there’s no problem as long as there’s no possibility of actually changing the past, a concept called the self-consistency principle.  For example, maybe you can travel to the past, but as soon as you try to kill one of your ancestors, some mystical force prevents you from following through.  This statement, which comes from the Stanford Encyclopedia of Philosophy, highlights the point: “We should note the crucial distinction between changing the past and participating in (aka affecting or influencing) the past.” 

So what do you think?  Is it possible to affect, influence, or participate in the past without changing the past?

If time travel into the past was possible, what kinds of things could you do without causing a temporal paradox?

In the next post, I’ll dig into this a little more. 

Shameless Self-Promotion: Who is Andrew Knight?

Yesterday a neighbor asked me, “Oh, you’re a physicist?  So what do you do?”

I hemmed and hawed and gave her a really half-assed answer that didn’t reflect the meaning or magnitude of what I’m doing.  So despite the risk of being a shameless self-promoter, let me clearly and confidently answer a few questions.

Who am I?

·       A philosopher of physics and mind.  This is my most recent identity, starting in 2018 when I began pursuing, full-time, answers to the hardest unsolved problems in physics and philosophy.

·       A rocket scientist.  I invented the Rotating Spindle Pump™, a rocket engine liquid propellant pump that is lighter and less expensive than traditional turbopumps.  It was recognized as a Modern Marvel of The History Channel Invent Now^TM Challenge.  I am the sole inventor on ten U.S. patents covering RSP and other rocket engines and pumps.

·       An inventor.  I am the sole inventor on an additional seven U.S. patents on a variety of technologies including software, information compression, and consumer products.

·       A teacher.  I taught high school physics (including AP physics) as well as mathematics at several colleges, including the University of Georgia.

·       An eternal student.  I am currently taking graduate physics courses at East Carolina University, the 10^th university I’ve attended.  Others include UF (B.S.), MIT (S.M.), Georgetown (J.D.), Princeton, NYU, Shenandoah U, Universidad de Guadalajara, USF, and UAH.

·       A nuclear engineer.  I received my undergraduate and master’s degrees in nuclear engineering.

·       An entrepreneur.  I started two small hospitality businesses in Maine: the Inn at the Agora and the Agora Grand Event Center, which I sold in 2018.

·       A world traveler.  When my wife and I returned from our travels this past summer, I had traveled to my 101^st country.

What am I currently doing?

·       Pondering and solving hard problems about consciousness and the physical universe

·       Documenting, publishing, and explaining this progress via this blog, my channel on YouTube, and papers (especially this, this, this, and this).

What problems have I solved?

·       Is quantum computing possible or scalable?

·       Is Schrodinger’s Cat (or Wigner’s Friend or macroscopic quantum superpositions in general) possible?

·       Does the brain cause consciousness?

·       If the brain produces conscious identity, can the brain be copied?

·       Can conscious states be copied?

·       Is mind uploading possible?

·       Will artificial intelligence (AI) ever be conscious?

·       Is consciousness algorithmic?

·       Is the physical world reversible?  Is it deterministic?

·       Does consciousness cause collapse of the quantum wave function?

·       Do quantum waves always evolve linearly (i.e., unitarily and reversibly)? 

·       Is the above assumption (“U” or “universality”) a valid inference?

·       What are quantum superpositions?  Are they relative?

·       What does conscious identity imply about the Many Worlds Interpretation (MWI) of quantum mechanics?

·       The measurement problem

·       The black hole information paradox

·       Did the Afshar experiment demonstrate a paradox in wave-particle duality?

·       What is the role of gravity in decohering quantum superpositions?

·       Is time travel possible?

·       What scientific evidence is there for the existence of God?

·       Does infinity exist?

What problems am I working on?

·       Is there an afterlife?

·       Are conscious states history dependent?

·       Are there more possible conscious states than can be produced by the brain?

·       Do we have free will?

·       Information creation: Is Planck’s constant (ℏ) actually decreasing?  If quantum uncertainty is decreasing with time, what does that tell us about the past?  Can we extrapolate backward in time to the Big Bang?

·       Are thoughts private?

·       Why is it always now?

·       What causes the arrow of time?

What I have already accomplished is significant and important, whether or not anyone else recognizes or validates the results.  I am excited to have the time, energy, and mental capacity to continue working on these fascinating, difficult, and very meaningful problems.

FYI: Here is a selected portion of my current CV (curriculum vitae).

All Contradictions Are False

Today I received a great question from a reader that was worth posting here.  First, he references my paper on the impossibility of scalable quantum computing and says:

There seems to be nowhere for anyone to discuss it. Academia is sealed off to the public nowadays. 

Agreed.  That’s because, as I discussed in this post, there is an unholy marriage between the prophets of quantum computing and the Cult of U (i.e., the fanatical belief that quantum wave states always evolve linearly).  After attempting to submit several papers to the arXiv that questioned the assumption of U, I had assumed I was blacklisted until the unexpected happened.

Then, he asks a key question:

We hear (ad nauseum) that the spin on an electron can be both 'up' and 'down' simultaneously, but what does that actually mean?  It may be true in ket space, but it cannot be true in actual space.

First, let me point out that this should be a really stupid question.  No intelligent person should ever have to ask, “What does it mean if X is true AND X is false?”  Logically, that looks like X ∩ ¬X, which any logician will say is a contradiction and therefore a false statement.

But here’s the thing… the reader’s question is a perfectly reasonable and rational question in the physics world, because we are constantly bombarded by characterizations of quantum superpositions that are completely nonsensical.  For example, Schrodinger’s Cat is constantly described by physicists as “a cat that is both dead and alive simultaneously.”  But this is a contradiction and is necessarily false. 

This is the kind of logical error that physicists routinely make.  I have tried to point them out in papers like this and this.

If an object is in quantum state described by |A> + |B>, it is simply not the case that the object is in both state |A> and |B> simultaneously.  In fact, none of the following statements are true:

·       The object is in state |A>.

·       The object is in state |B>.

·       The object is not in state |A>.

·       The object is not in state |B>.

Indeed, there simply is no fact about whether the object is in state |A> or |B>.

In other words, dear reader, you have been misled by physicists who either don't understand basic logic or are intentionally trying to deceive the world with bad characterizations of quantum mechanics, because that is what is necessary to keep the investment money flowing into quantum computing.

By the way, infinity itself is also a contradiction.  As I discuss in this post, atheist physicists like to posit infinitely many universes to account for the existence of something that has a zero probability.  But all contradictions are false, so infinity cannot be used to imply anything true.

Andrew Knight is Qualified to Endorse

The universe is more unpredictable than I had imagined. 

As I discussed here, I was certain I had been blacklisted from the arXiv.  I have submitted ten papers to it, five of which question the assumption of U (the assumption that quantum wave states universally evolve linearly/reversibly).  Exactly five of those ten papers were rejected… can you guess which ones?

Two days ago, I submitted my new paper (“Wigner’s Friend Depends on Self-Contradictory Quantum Amplification”) to several preprint archives, as well as the arXiv just for the hell of it.  As with most of my submissions to arXiv, it immediately went “on hold” and I fully expected it to be rejected.  Amazingly, it was published last night and can be accessed here.

I don’t get it.  This new paper is not all that different from several others I’ve submitted.  The argument is somewhat different, and it’s shorter and clearer.  It also directly responds to an article that was published last year in Physical Review Letters that essentially shows that reversible measurements are a logical contradiction.  But, like my other articles that have been rejected by arXiv on the indefensible basis that they were “unrefereeable,” this article bluntly rejects U – and the physical possibilities of Schrodinger’s Cat and Wigner’s Friend – on a purely logical basis.

What’s even more amazing is that I submitted it under the subtopic physics.hist-ph (history and philosophy of physics), but some anonymous arXiv moderator moved it to quant-ph (quantum physics), which makes it my third arXiv publication in that topic.

Here’s why that’s amazing.  You can’t submit to arXiv unless someone, who is already regarded as sufficiently competent on a particular topic, endorses you in that topic.  This is one way that arXiv tries to keep out the crackpots.  (As it turns out, Scott Aaronson was the person who originally endorsed me for the quant-ph topic years ago.  He also sent me a snarky email this morning adamantly opposing the argument in this new paper.)  So how do you become an arXiv “expert” on a particular topic?  By getting three articles on arXiv in that topic.  I had already had three articles in the physics.hist-ph topic, but I only had two in quant-ph.  Indeed, I submitted the current article to the physics.hist-ph topic. 

But not only was my article published on arXiv, someone intentionally reclassified it as quant-ph, which makes it my third article in that topic.  I am now “qualified to endorse” in the quant-ph topic on arXiv.  In other words, by arXiv’s own standards, I am now, due to the reclassifying and publishing of an article that rejects the assumption of U, sufficiently competent in quantum physics to help screen out other crackpots.

WTF.  Seriously, WTF.  Either I'm finally getting heard, or someone at arXiv made a huge mistake.  Smart money's on the latter.

Schrodinger's Cat is Dead... and its Proponents are Braindead

It has become clear to me now that there is an entire industry that thrives on the ambiguity inherent in Schrodinger’s Cat and Wigner’s Friend. 

They are both based on contradictory assumptions.  And contradictions are false.

I have explained it in a simple paper understandable by anyone, including by those in the academy whose prestige and paychecks depend on perpetuating the contradictions.

The paper is here.  It won’t be published, but I don’t care anymore.  Grass is green and the sky is blue, and even if 10,000 academics publish papers to the contrary, all they are doing is perpetuating a system of mutual masturbation which is not interested in – and does not value – truth. 

It is now extraordinarily clear to me that any physicist who actually believes that Schrodinger’s Cat is physically possible in the actual universe is – to use the words of asshole Richard Dawkins – either ignorant or stupid.

I am done with this silly game.

Does the Brain Cause Consciousness? Part 3

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.[1] 

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.[2] 

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 S2_M (which creates conscious state C2_M), while on Venus, your physical state S1 would change to S2_V (which creates conscious state C2_V).  State C2_M might be the conscious experience of looking out at a vast orange desert, while state C2_V 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, C2_M or C2_V?  There are only three possibilities:

·       Neither

·       Both

·       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 (S2_M on Mars and S2_V on Venus) also can’t affect each other.[3]

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 (C2_M, C3_M, C4_M, 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 (C2_V, C3_V, C4_V, 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, C2_M or C2_V?  As I said before, there are only three possibilities, which I’ll analyze below:

·       Neither

·       Both

·       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 S2_M (which produces your conscious state C2_M) long before a signal can be sent to stop it.  Therefore, you will experience conscious state C2_M, so the correct answer cannot be “neither.”

Both.  Maybe you will experience both conscious states C2_M and C2_V.  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 C2_M is created by physical state S2_M, which is affected by stuff on Mars, while your conscious experience of C2_V is created by physical state S2_V, which is affected by stuff on Venus.  For example, if state C2_M 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 S2_M.  But information about that interaction is inaccessible to whomever is experiencing state C2_V on Venus, once again because information does not travel fast enough between the two planets.  Therefore, whoever is experiencing state C2_V on Venus cannot also be experiencing state C2_M on Mars.  Therefore, maybe you’re experiencing state C2_M or C2_V, 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 C2_M or C2_V.  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 C2_V on Venus), because it takes much longer than one second for information to travel between the two planets.[4]  Therefore, the universe cannot “choose” between C2_M or C2_V 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 S2_M (which produces C2_M) on Mars and S1 changes to S2_V (which produces C2_V) on Venus, there is no known physical means for the universe to somehow decide that you will experience only C2_M or C2_V (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.[5]  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. 

---

[1] 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!

[2] 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.

[3] To use physics language, the creation of states S1 on Mars and Venus (and their subsequent evolutions to S2_M and S2_V, respectively) are spacelike separated events.  The argument I’m making here applies equally to timelike separated events, which I discuss in my paper.

[4] 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.

[5] 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.