Tuesday, October 8, 2019

I don’t understand double-slit interference. Do you?

So, yes, the “Adding Probabilities” method is wrong.  As it turns out, the reason I was getting such bad distributions when using Mathematica to produce graphs for the (correct) “Adding Fields” method is that I had not properly adjusted the phase for each field point source within each of the slits.  When I do that, it produces distributions in the near- and far-fields that, I think, are consistent with what would be observed in actual experiments.

But this essay is important to me for several reasons.  First, it underscores one of the problematic assumptions I’d been making, namely the assumption that there is some reality about where, in each slit, a particle is located.  Identifying that as incorrect helped me come to what I believe is a better understanding/interpretation of QM, which I describe here, in which a superposition is indicative of a lack of a fact.  Second, writing it helped me to understand the relationship between single-slit Fraunhofer distributions and double-slit interference distributions.  Third, it makes some good points about problems in QM, and is mostly correct if you’ll ignore any nonphysical wackiness in the “Adding Fields” graphs.

I have made huge progress in understanding physics over the past couple years and wouldn’t be where I am today without the experiences of yesterday.

Friday, June 21, 2019

Is It Possible to Copy the Brain?

The science fiction plot involving copying brains or uploading minds onto computers or fighting conscious AI or teleportation yada yada yada is everywhere.  Black Mirror wouldn't even exist without these fascinating ideas.

Every one of these plots depends on the assumed ability to copy brains or consciousness, or on the assumption that consciousness is algorithmic, like software running on a computer.  These are very related assumptions: all algorithms can be copied and executed on any general-purpose computer, so if consciousness is algorithmic, then it should be possible to copy conscious states and/or duplicate brains.

Let me be blunt: every science nerd on the planet (including me) has, at some point, wondered about and been intrigued by the possibility and implications of "brain copying."  (Although really I mean the more general notion that one's consciousness can be copied, whether by digitizing consciousness, physically copying the brain, whatever.) 

But here's something weird.  VERY few scientists have actually questioned the assumptions that conscious states can be copied or that consciousness is fundamentally computational.  For instance, if you Google the exact phrase "impossible to copy the brain" a total of ZERO results are found, but if you don't question the possibility of brain copying, then the exact phrase "copy the brain" yields over a MILLION results.  Does it seems strange that despite our fascination with AI, teleportation, mind uploading, and so forth, that this particular post might be the very first in the entire history of the Internet to state, in these words, that it might be impossible to copy the brain?  Really?!  No one has ever said that phrase on the Internet before?  (BTW there are lots of other such phrases, printed at the bottom of this post.)

These assumptions are so ingrained within the scientific community that most young physicists, neurobiologists, engineers, etc., don't even realize that they are making such assumptions, and those that do are unlikely to question them.  Famed philosopher John Searle once pointed out that "to deny that the brain is computational is to risk losing your membership in the scientific community."  Entire industries are even being launched (mind uploading, digital immortality, etc.) on the underlying supposition that it's just a matter of time before we'll be able to digitize the brain, or create a conscious computer, or create a perfect duplicate of the brain.  Are these assumptions valid?

Sir Roger Penrose (Oxford) argues that consciousness cannot be simulated on a computer because, he claims, humans are able to discover truths that cannot be discovered by any algorithm running on a Turing machine.  However, despite his eminence in the fields of mathematics and physics, he is still criticized by the "mainstream" scientific community for this suggestion.

Scott Aaronson (U. Texas @ Austin) asks in his paper, "Does quantum mechanics ... put interesting limits on an external agent's ability to scan, copy, and predict human brains ... ?"  He says he regards this "as an unsolved scientific question, and a big one," and then gives one possible explanation of how physics might explain that conscious brains can't be copied (if in fact they can't).  In a blog post, he points to an empirical fact "about the brain that currently separates it from any existing computer program.  Namely, we know how to copy a computer program ... how to rerun it ... how to transfer it from one substrate to another.  With the brain, we don't know how to do any of those things."  In both works, he is careful not to offend the majority, with self-deprecating comments about expecting to be "roasted alive" for his dissension from "the consensus of most of my friends and colleagues."

There are a few other scientists who cautiously suggest that brains can't be copied or that brains aren't computers (one example here).  I myself have written a paper (preprint here or related YouTube videos herehere and here) that argues that consciousness is not algorithmic and can't be copied, in part because consciousness correlates to quantum measurement events that occur outside the body.  But, let's face it: for the most part, very few scientists question these assumptions.

I assert that the following assumptions pervade academia and popular science, and that they are unfounded and unsupported by empirical evidence:
a) That consciousness is computational/algorithmic;
b) That consciousness can be duplicated; and
c) That brains can be copied.

Here is my question: What empirical evidence do we currently have for making any of these assumptions?  I think the answer is "none," but I could be wrong. 

If you are going to answer this question, please consider these guidelines:
*  Please provide actual empirical evidence to support your point.  For example, if you think that brains can be copied, then linking to a bunch of papers in which neurobiologists have sliced rat brains (or whatever) is inadequate, because that says nothing to support the assumption that brains can be copied over the assumption that brains cannot be copied.   And extrapolating into the future ("If we can slice rat brains today, then in 50-100 years we'll be able to digitize them and copy them...") is not evidence for your point.  On that note...
*  Please do not talk about what is expected, or what "should" happen, or what you think is possible in principle.  (The phrase "in principle" should be banned from the physicist's lexicon.)  Please focus on what is actually known today based on scientific inquiry and discovery. 
*  Please do not bully with hazy notions of "consensus."  Scientific truth does not equal consensus.  I don't care (and nor should you) what a "majority" of scientists believe if those beliefs are not founded on scientific data and evidence.  Further, considering that anyone who openly questions these assumptions has to apologetically tiptoe on eggshells, for fear of offending the majority, it's difficult or impossible to know whether there really is any consensus on this issue.
*  Please be aware of your own assumptions.  For example, if you reply that "consciousness must be capable of being simulated because it is part of the universe, which is itself being capable of being simulated," note that the latter statement is itself an unproven assumption.

Additional comments:
The following search terms in Google yield either zero or just a few results, which underscores how pervasive the assumptions about brains and consciousness are:

“impossible to copy conscious”
“impossible to copy consciousness”
“not possible to copy consciousness”
“possible to copy consciousness”
“possible to copy conscious”
"cannot copy conscious"
"cannot copy consciousness"
"impossible to duplicate conscious"
"possible to duplicate conscious"
"possible to duplicate consciousness"
"impossible to duplicate consciousness" 
"cannot duplicate consciousness" 
"cannot duplicate conscious"
 “not possible to copy brain”
“impossible to copy the brain”
“not possible to copy the brain”
“cannot copy the brain”
"cannot duplicate the brain"
"impossible to duplicate the brain"
"possible to duplicate the brain" 
 “consciousness cannot be algorithmic” 

Thursday, June 20, 2019

The Physics of Free Will

I know the topic of free will has been debated endlessly for millennia, and everyone has their own opinion.  However, I’ve read and searched endlessly, and I can’t find anyone who addresses or answers the following problem.

Let’s say that I perceive that I have the choice to press button A or B.  There are only three possibilities:
a) There is no actual branching event.  The perception is an illusion.  The button I press is entirely predetermined.  (That doesn’t imply that the universe as a whole is deterministic, but that indeterminacy is irrelevant to my perception of a free choice.)
b) There is a branching event, but it is quantum mechanical in nature.  In other words, the button I press actually depends on some QM event (whether you call it measurement, reduction, or collapse), so while the outcome is not predetermined, it is random.  The perception that a branching event was about to happen was correct, but the perception that I can control it is an illusion.
c) There is a branching event, and my free will caused the outcome.

In case a), my “choice” is simply a prediction about the future.  But there are several problems with this:
1) Why would I ever perceive as possible an event that is actually impossible?  (If pressing button A was predetermined, then pressing B is an impossible event.)
2) What is the advantage of making a prediction if awareness of the predicted outcome will not affect anything that will happen in the future?  In other words, if I can’t DO anything to change anything (because I don’t have free will), what’s the point in predicting? 
3) What is the advantage of perceiving free will when I am actually making a prediction?  When I drop a ball, I predict it will accelerate downward toward the Earth.  But imagine if I (falsely) believed I had free will over that ball... “OK, am I going to drop the ball UP or DOWN?  Hmmm... today I’ll decide to drop it DOWN.”  What would be the point of that false perception? 

The case of b) isn’t much better, because my “choice” is, again, just a prediction about the future (possibly coupled with measurement of a random QM event).  The same problems arise.

Note that my perception of free will is limited to my body, and not even my entire body (for example, I don’t think I can consciously control my digestion process).  In fact, I only perceive “free will” with regard to a few aspects of my body, such as motions of my hands and fingers.  But what is true is that I have never EVER once observed the experience of NOT having free will over those parts.  For example, I have never decided to raise my right hand, but then my left hand rises instead.  I never raise my hand and then say, “I didn’t do that!” 

But that COULD have been the case.  I could have been born into a world in which I just observed things happening... where my body was no different from a dropping ball or a planet orbiting a star... where it’s just an object that moves on its own and I experience it.  In other words, why am I not just experiencing the world through a body that moves on its own as if I were just watching an immersive (five-sense) movie?  It’s not like we need to believe in free will.  For example, we are perfectly fine watching movies or riding roller coasters, full well knowing that we can’t control them.  Why couldn’t we just be passing through the world moment-to-moment, just experiencing the ride, without any perception that we have free choices?  In other words, if a) or b) above is true, we need to explain WHY I perceive the freedom to press button A or B, but also why my choices are always 100% consistent with the outcome.

That’s a real problem.  Because now we have to explain why the universe would conspire to:
* Fool me into believing that I have a choice when I don’t; AND
* Fool me into believing that the outcome is always consistent with what I (mistakenly) thought I chose!

Why would the universe fool us like that? 

As an aside, please don’t answer with “compatibilism,” which is the philosopher’s way of avoiding the question of free will.  You can look it up, but I regard it as a non-answer.  Even famed philosopher JohnSearle agrees that philosophers haven’t made any progress on the free will question in the past hundred years.

Tuesday, June 11, 2019

Why Mind Uploading and Brain Copying Violate the Physics of Consciousness

I just finished creating a video, now posted on YouTube, that attempts to prove why the laws of physics, particularly Special Relativity and Quantum Mechanics, prohibit the copying or repeating of conscious states.  This time, I introduce the Unique History Theorem, which essentially states that every conscious state uniquely determines its history from a previous conscious state.  If true, then the potential implications are significant: consciousness is not algorithmic; computers (including any artificial intelligence) will never become conscious; mind uploading, as well as digital immortality, will never be possible; and teleportation and any form of brain copying or digitization will remain science fiction.

The video, which lasts about an hour and a half, is here:

However, if you want a brief SUMMARY of the two main videos, a 17-minute video is posted on YouTube here:

Please keep in mind that the above summary video is a great introduction to the proofs and arguments in the main videos, but that the arguments themselves are truncated.  

Tuesday, June 4, 2019

Can Physics Answer the Hardest Questions of the Universe?

At some point during an intro to philosophy class in college, I was first exposed to the classic "Brain in a vat" thought experiment: how do I know I'm not just a brain in a vat of goo with a bunch of wires and probes poking out, being measured and controlled by some mad scientist?  That was a few years before The Matrix came out, which asked essentially the same question.

So -- are you a brain in a vat?  And how could you know?

This is just the tip of the iceberg; once we start down this path, we come face-to-face with more difficult questions.  "What creates consciousness?"  "Can consciousness be simulated?"  "If I copy my brain, will it create another me, and what would that feel like?"  And once we've fallen down the rabbit hole, we see that there are a thousand other seemingly unanswerable questions... questions about free will, the arrow of time, the nature of reality, and so forth.

I think physics can help answer these questions, and in fact I think I have answered a couple of them to some degree.  For example, I don't know (yet) whether I'm in a simulation, but I think I do know whether or not I am a simulation.  Here is my first YouTube talk in which I explain why consciousness cannot be algorithmic, conscious states cannot be copied or repeated, and computers will never be conscious:

If you prefer a written explanation, here is a preprint of my article, "Refuting Strong AI: Why Consciousness Cannot Be Algorithmic."

I am also working on another proof of the same conclusions from a different angle.  Here is a preprint of my article, "Killing Science Fiction: Why Conscious States Cannot Be Copied or Repeated."  I'll post a link to a YouTube talk on this paper as soon as it's available.