Has quantum computing debunked the law of noncontradiction?

I randomly came across an article and it said something potentially troubling:

Whether it’s calculating your taxes or making Mario jump a canyon, your computer works its magic by manipulating long strings of bits that can be set to 0 or 1. In contrast, a quantum computer employs quantum bits, or qubits, that can be both 0 and 1 at the same time, the equivalent of you sitting at both ends of your couch at once.

Is this implying that this quantum computation can defy the law of non contradiction?

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It’s implying that by holding back from a definitive conclusion until all the data has been processed, a seemingly unreachable correct answer can be found.

I think this is the key passage:

“The waves interfere so that the wrong factorizations cancel one another and the right one pops out. “


This is pseudo science, folks. The point is to get you to accept that there are (or will be, in the not-so-distant future) computers that can guess the unguessable, in zero time. To get you to accept this, a complicated story about qbits and quantum states and interference and wave functions is presented to you. You’ll try to get your head around it, and you’ll almost succeed, but never quite — it’s impossible because the story doesn’t completely add up. Yet you’ll say “I get it, this quantum computing thing.” It’s a subtle vanity. And thus you’ll become uncritical of the magic that quantum computers perform. You’ll say, “This isn’t magic, this is technology, based on science that I’ve studied. Nothing out of the ordinary.” And so you’ll lose your way yet further, in this simulation called “the world”.

Ohhh… the Devil is smart. He knows you so much better than you know yourself.


I think the problem is that quantum mechanics defies the law of non-contradiction. Schrödinger’s cat and Heisenberg’s uncertainty and others. Quantum computing uses those naturally “contradictory” items to compute more quickly. It does not introduce more contradictions, it just uses the contradiction that is already present.

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I’m no expert but I’m fairly sure the law of non-contradiction is a philosophical concept. Philosophy doesn’t apply very well to quantum physics, because (the little bit of it I understand!) quantum physics is inherently contradictory. Light behaves as BOTH a wave and a particle at the same time. Electrons can be in more than one place at the same time. The double slit experiment proves that light can take more than one path simultaneously (or something like that, I think).

Regardless, philosophical concepts are perfectly wonderful, but they don’t explain key parts of the natural world.

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Not quite, that is “popular science”, where science is simplified beyond recognition.

It is mostly useless, but “pseudoscience” is somewhat different category of “sciency” silliness.

Of course, bad “popular science” attracts even worse philosophy/

No, there are no contradictions in Quantum Mechanics.

Accept that an elementary particle is neither a particle, nor a wave, but something else (although in some ways similar to both), and those fake contradictions vanish.

There are more things a bit like that. For example, “electron holes” are classified as quasiparticles.

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I understand the distinction between popular science and pseudo science. I agree that popular science is simplified science, possibly “beyond recognition” as you say. But what we have here (OP’s linked article on quantum computing) though, is not popular science. It truly is pseudo science – if we go by the strict meaning of the term pseudo anyway. Pseudo science is meant to deceive, not to simplify. It isn’t “sillyness”, for that term suggests a certain jokiness and light-heartedness. Pseudo science is actually carefully crafted, intentional falsehood.

If we accept a contradiction, then contradictions disappear? Isn’t that a contradiction? Your particle/wave (I think they should be called parve) goes through a double slit as both a particle and as a wave simultaneously?

How does replacing this contradiction determine if Schrödinger’s cat needs to be fed? Or establish momentum and position simultaneously?

…is either alive, or is dead. Not both.

If light behaves like a particle and like a wave, and if something can’t be both a wave and a particle, then either light is a wave acting like a particle, a particle acting like a wave, or something else which acts like both but is really neither.

All this junk… ugh. If non-contradiction was “debunked,” could also be “not debunked”? You see the issue?

That was Schrödinger’s point, that the cat was dead or alive. And that is the case with classical physics, but not with quantum mechanics. A particle can exist as a particle or a wave or possibly both. At a certain point, the “wave function collapses” and possibly both becomes one or the other. The contradictions are real in the quantum realm, and a qcomputer uses them

The interesting part of this article is that a quantum computer seeks to have something at a macro level, =thousand of atoms, that behaves like a quantum particle.

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If a particle being a wave is a real contradiction, then it can’t happen. If it can happen, then it’s not a real contradiction. Clearly, a cat can’t be both alive and dead - it is ALWAYS one or the other, even if we don’t know which. So… I fail to see the point. The issue of the OP is whether truth is a thing if quantum mechanics xyz. Well, if it isn’t, then there isn’t a truth about quantum mechanics either.


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Computer technology is based on some simple principles. As the article says:

your computer works its magic by manipulating long strings of bits that can be set to 0 or 1. In contrast, a quantum computer employs quantum bits, or qubits, that can be both 0 and 1 at the same time

By utilizing qubits, Google has been able to accomplish a task in 200 seconds that would take “a state-of-the-art classical supercomputer would take approximately 10,000 years.” This quote is from this paper that announced Google’s achievement.

As I said earlier, quantum computing does not disprove the noncontradiction principle. This is a statement of what quantum computing has done which in no way affects noncontradiction.

This does not eliminate the issues that quantum mechanics raises with respect to non-contradiction. The information in a qubit cannot be expressed with just the numbers 0 and 1. It is not either true or false, but possibly both. Or perhaps it can be represented by 0 & 1, but it would take so long to do so, it is practically impossible.

Just like this note is a ridiculously long attempt to explain what is being said.

Sure - as long as the string is not both 0 and 1 at the same time in the same sense. Otherwise, forget truth, there’s just experience.

I’m fairly sure “truth” as you’re using for it does not exist in the natural world. “Truth” is not a scientific concept but a philosophical one (and theological), you will be sorely disappointed if you apply philosophical concepts to the natural world.

Philosophy deals with what is in our heads (i.e. ideas). Science deals with the reality around us. Reality conforms to ITS laws, not our beliefs about what those laws should be.

And yes, as I understand it, quantum mechanics requires that certain contradictory things be happening. Individual particles can, in the same way, be in two different places at the same time. That just means our philosophy needs to be updated.

Should I think that what you are saying is… true? Help me to understand…

Sorry - everything you have said here is so laden with values it is difficult even to begin to unpack it.



What I’m saying is: the law of non-contradiction is philosophy. It deals with philosophical things.

Quantum mechanics (and all science) deals with the natural world. Philosophy does not explain the natural world (for a great example of how badly philosophy can fail to explain the natural world, just read Aristotle of physics - he is laughably wrong). In quantum mechanics scientists have observed phenomenon that can only be explained as contradictory.

The most famous is the wave-particle duality. Light (and other stuff) can be both a wave and a particle at the same time.

There are other examples as well. There are situations in which an electron is observed to be in two places at the same time.

How does this happen? I have absolutely no idea. Sadly I barely understand science.

What I do know, however, is that the natural world follows ITS laws, not ours. And one of its laws clearly allows what we call contradictions.

In the article in the OP, scientists have built a computer that has bits that can be both 1 and 0 at the same time. Essentially scientists are using quantum mechanics to help process data faster. Which is really cool.

It means nothing about the philosophical or theological worlds. It means nothing about “truth.”

I’m sorry… the problems with your post are so numerous I don’t even know where to start.

How about I just say your post is untrue. I don’t mean to sound rude but… my request to “help me understand” was rhetorical. The whole sense of what you are saying is absurd. You could appeal to scientific instumentalism and the pragmatists, but even that will only get you so far - they would not say the PNC just goes out the window when we do “science,” whatever “science” is. They might say it is irrelevant to achieving a goal insofar as the reality of a mechanism does not matter so long as how it is used reaches the goal, but they would not say that there simply is no truth about it, or they would say that truth is in fact defined by instrumentality (like William James)… which still would have the PNC involved, albeit with a different application (and a wrong one - as this too is self-defeating).


Using the science of quantum mechanics as a proof that reality on some level doesn’t conform to the principle of non-contradiction is a pseudo-science and is due to a lack of understanding more than evidence of something. A thing acting as both a wave and a particle at the same time is not the same thing as a square-circle.

Even when you observe a thing acting as both a wave and a particle the principle of non-contradiction still applies since you can’t say that a thing is acting as both a wave and a particle at the same time and that this same thing is only acting as a particle at the same time even though it is also a wave. It’s an impossibility.

So the principle of contradiction does apply to objective physical reality at the quantum level and what is really happening is not a contradiction but rather that you are conflating macro objects with quantum objects and do not really understand what you are describing when talking about wave-particle duality.

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It’s only when you put quantum behavior in macro-behavior terms that it seems like a violation of the law of non-contradiction.

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Actually, a square circle is a very good way of describing particle and wave problem. You can describe a beam of light in terms of waves, or in terms of particles, at one and the same time. I remember calculating the de Broglie wavelength of a watermelon in a workbook I had.

The problem lies in using macro level ideas, like particles and waves, to describe something that is both. The model is inadequate.

The inadequacy of models is basic to quantum mechanics, which is why it brings into question the noncontradiction principle. We are used to thing being true or false, and structure our models around that idea. Quantum physics puts us in a situation where that model is inadequate. That kind of a metaphysic does not apply in a world where something can be both wave and particle at the same time. An adequate description of the reality relies on probabilities, paradoxes, chaos theory, etc.

Facts are greater than theory, and the fact is that quantum level interactions are better understood with a nonbinary system of information. That has caused people to question whether binary systems, like noncontradiction, are adequate to describe macro level realities. It is not an outrageous idea, or it is only outrageous if you do not understand the scope of it.

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