If our particles have no identity, how can we? (2015) | Hacker News Reader

If our particles have no identity, how can we? (2015)

nautil.us

20 pointsdnetesn52 comments

I would say that this is not a good article. It touches several topics and mixes them up without really being good or clear on any of them. You could write an article about the concept of identity as it applies to humans, you could write an article about this imposter case, you could write an article about identity as it applies to electrons or more generally fermions and bosons, which don't both behave the same under exchange of two particles, you could write yet another article trying to shed some light onto the wave and particle nature of fundamental particles. There would be enough things to discuss for any of these topics to get an long article out of it, heck, you could write entire books on them. But this article just grabs random pieces from all of the topics and leaves you not any wiser on any of them.

It fits a trend in modern philosophical publishing. Part of the reason I'm so quick to stop (or not even start reading) articles like this.

The answer is: we are not things, we are states (and so are particles).

http://blog.rongarret.info/2015/02/31-flavors-of-ontology.ht...

The answer is: we are not things, we are states (and so are particles).

I quickly read your article - and I think I read it before - and you make some points I agree with and some with which I disagree. But I think this condensed statement you made in your comment is wrong. Not everything can be a state, you need something that can be in a state or in different states. Less importantly I don't think state is a good word to describe what I am, the usual meaning of state is something that does not change. I obviously change, my body as well as my personality, so it seems more appropriate to me to talk about sequence of states over time. Maybe even my first point is just due to a disagreement on terminology but it seems at the very least very confusing to describe fundamental particles, macroscopic objects, and persons with the same term implying identical or at least similar nature.

> you need something that can be in a state or in different states

No, you don't. That's the erroneous thinking that led people on the fruitless search for the "luminiferous aether" in the late 19th and early 20th century. Ultimately, everything in our universe emerges from the quantum wave function. I suppose you could say that the wave function is "something" but it is definitely not "some thing".

If the universe is just the wave function of the universe, then nothing is really a thing with the naive interpretation of a material thing. But that is essentially the distinction I meant, there must be a fundamental thing that we can then chop up into pieces to get the things we are talking about in everyday life. And there would probably still be good reasons to distinguish between fundamental particles and humans because fundamental particles would still be atomic things emerging from the wave function while I would be a certain, slowly changing over time, arrangement of fundamental particles.

What I am not really sure about is whether it is consistent with our understanding to say that an electron is just its wave function. We usually use the wave function to describe the state of the electron but we think about the electron as a separate entity with different possible states and the wave function only describes the state the electron is in at a specific point in time. More importantly the wave function of an electron is not a unique thing, if an electron really was just its wave function, which one is it, the one in location space or the one in momentum space or yet another one?

That is an excellent question. The answer is that electrons really are their wave functions. They are not "particles". The explanation is too long for an HN comment but here's a reference:

http://www.flownet.com/ron/QM.pdf

or if you prefer a video:

https://www.youtube.com/watch?v=dEaecUuEqfc

I have seen the talk and may have read the paper, but I remember it mostly for talking about the relation between entanglement and measurements but not for addressing the fundamental nature of particles. But even without rereading the paper I have another point that may cast some doubt onto the idea of the wave function being fundamental. There seems to be growing evidence that space and time are not fundamental which, in my opinion, makes it sound rather unlikely that the wave function will turn out to be the fundamental building block of the universe given the extend to which it depends on these concepts. Essentially I think the most honest answer right now would be to say that our understanding of physics is far from good enough to tackle the question of what is really fundamental and what is just emergent.

The "fundamental nature of particles" (according to QIT) is that there are no particles.

> There seems to be growing evidence that space and time are not fundamental

Yes. Time actually emerges naturally from QIT. See:

http://blog.rongarret.info/2014/10/parallel-universes-and-ar...

There are models where electrons are particles always, they are classified under the group of "pilot wave theories." At present we have proofs that these metaphysical questions are at present unanswerable, which came out many years ago. For some reason nobody wants to take the equivalency proofs seriously, and the ontological debates continue.

You can have particles only if you're wiling to give up on locality. That's a steep price.

This was a much better read on the subject than the original article, IMHO.

These quotes in particular stood out to me.

> Arrangement is everything.

> You are a computational process, reified as an arrangement of electrical impulses in a human brain.

I honestly like how the author makes a stab at God, even if it's loaded.

The author is the commenter 'lisper

Interesting because I don't love the distinction between states and things, but that'll happen when you try to summarize this topic into a sentence.

Thanks! :-)

If you attempt to identify a canonical "you" which ignores the basic fact that your particles are entangled with virtually every other particle in the visible universe, you're starting with an assumption wrong enough that of course you're eventually going to run into some absurdities.

If you create a universe which is indistinguishable from our own, even in a quantum sense (i.e. you recreate the quantum state that our universe is in), then you'll necessarily have created a universe with an indistinguishable copy of yourself in it. But in fact that's the only way to create an indistinguishable copy of yourself in the first place! You can't reduce the problem any further than this.

In other words, this entire "paradox" boils down to a vague understanding of the word "identity".

Or a very good understanding of where it fits in today's (or 2015's) linguistics. It's technical, and vague, perfect for a piece like this, where the author can say a lot of pretty "profound" stuff without actually saying anything at all.

When you shake hands with someone, you're connected to them. Who is who? Spooky.

I think there's a cottage industry of finding confusing thinkpieces in nothing.

That's kinda the root of the problem with this article. It's not about the physical particles, it's about our sense of self (which yes, is probably an artifact of some crazy particle interactions). The distinction is that your self doesn't magically get redefined just because you touch something else, or because you shed some skin, or anything like that.

> your self doesn't magically get redefined just because you touch something else

Phineas Gage (and everyone else with brain damage) is a counterexample in one sense. The famous statement "Gage was no longer Gage" is about as explicit as possible in support of the idea that touching something can redefine your self.

At a more fundamental level, there are chemicals which can penetrate your skin and bind to (therefore changing) your DNA.

Before saying "your self doesn't get redefined by X", you need a robust definition of what your "self" is.

Agreed, and good luck with that definition. It's going to depend on the physical space and only be related over time.

The buddhists went through this thought process and have decided that nothing has inherent identity. IT's called "emptiness" or "Shunyata". In general it seems a more philosophical question than scientific.

IMHO the Buddhists threw out the baby with the bathwater. Just because nothing has inherent identity (which is true) that does not mean that it makes no sense to assign an identity to the unique collection of memories and experiences that I call "me".

> that does not mean that it makes no sense to assign an identity to the unique collection of memories and experiences that I call "me".

Actually, that is not disputed - at least in some buddhist schools. Identity as an epiphenomenon is quite sensible, and they understood this. Well, some of them at least.

They also reject the idea of "self" :-)

I really like this. I personally tend to find myself reaching for the word "void" when I get caught up thinking about this.

In quantum field theory on curved spacetime backgrounds, the notion of a particle is observer-dependent. Particles are departures from the lowest energy state, but which state has lowest energy can depend on an observer's acceleration. Consequently, different observers can disagree about whether and which particles are present in a physical system. (This phenomenon is the theoretical basis for the Hawking Effect.)

If your particles aren't real, are you real?

It's silly to base a discussion of human identity on field quanta.

It is silly - not because the question is silly, but because the article ignorantly misses the fact that there's an established and much-discussed philosophical background to these questions, and the author seems completely unaware of it.

It would be hilarious if David Chalmers is right, and science is looking through the telescope the wrong way.

Instead of there being no subjectivity, perhaps there is only subjectivity - different points of view experiencing different elements of reality, loosely constrained by probabilities, limited only by relative complexity of perception, freedom of action, and processing power.

> And so when particles like our electron go unwatched, they become diffuse and placeless.

I'm curious, how is this demonstrated?

--------------------------------------------

I have a couple questions.

In the example of two electrons and the two boxes: can we not just say that they are one in kind thought two in number? This fits with Aristotle's understanding of a hylomorphic composite. As the two electrons are really both an electron (one in kind), but their accidental property of place differ (two in number).

What is the definition of a `wave`? It seems to me weird to say a thing is a wave because I understand a wave to be a property of something. A motion through a medium. So I have trouble understanding the notion that a thing is wave as such.

Nothing has identity, but it might be possible to write down an identity function that gives a set of things distinct identities. The more interesting question then becomes how those identity functions fail and under what circumstances.

Honestly, this means nothing to me. Not even trying to be mean, I just don't at all understand what you are saying.

I'm making a distinction about what identity is bound to and how it is bound. The way our brain presents the world to us it seems as if the things themselves 'have' identities, but it is some function that is being computed in our brain that makes those things distinct from each other. It is the structure of the function that gives distinctness. This inverts the question of whether things 'have' distinct identities, into whether it is possible to find a function that can distinguish between any set of things. My point about failure was that all identities as we think of them are something like a hash function with finite length, there is always a chance of collision and it is important to know how they fail. For example, if you pick primary DNA sequence as the definition for identity, then your functional will fail for all identical twins. If you pick some metric on facial structure as measured by a 2d camera, then anything that can evoke the same pattern on the sensor of the camera will be indistinguishable, even a picture of your face. This is not because these things do not 'have' unique identities, it is because the function we choose was bad. Proving that there is no function that can distinguish between two things is exceedingly difficult.

I see, it's not about the set, as I originally thought you were saying, but about the function (act) of identification. I am starting to agree a bit more.

A has no identity. B has no identity. C has no identity.

But perhaps {A, B, C} can have identity?

I guess my confusion is, how can anything have an identity if we just asserted that nothing does.

The same way that a pile of identical bricks can have no identity, but a home you build out of it could?

I guess my confusion is, how can anything have an identity if we just asserted that nothing does.

Provide a quote where I or anyone asserted that absolutely nothing has identity.

Are you serious?

> Nothing has identity, ...

Failed. Lose an intellectual point for leaving out the vital context.

If the elements are all identical with each other, then it seems like the only measurable identity you could attach to sets of elements is cardinality, right?

Ya, that is basically all you have left when you can't find any measurable differences. This is pretty much how the periodic table works.

The most interesting point, if you read the article, which from the comments no one actually seems to have done; she finishes with the idea: "Our identity is a state, but if it’s not a state of matter—not a state of individual physical objects, like quarks and electrons—then a state of what?"

The geek in me thinks of a program at rest on disk vs a running program.

But running programs have state too. I stopped reading this half way because the author really doesn't have anything to say here. But I can understand that it's a thought provoking piece.

Different states.. state of an electron on disc used by every execution of a program vs the very different state of a program after it's been running for some time vs any other invocation of that program.

edit: it's what makes debugging so much fun :D

Running program, with another running program reflecting on what the first program is doing. And maybe vice versa :)

My favorite consequence of simple things having no identity is this. Every oxygen atom that you breathe is a superposition of having been many places a century ago, including in every lungful of breath that anyone anywhere was breathing. It isn't "x atoms were in so and so's lungs", EVERY atom both was and wasn't.

Honestly stopped reading about half way through. It seems obvious to me that we are identified just as anything. And just as anything else, it may not be perfect. I'm sure if you could copy me perfectly (which you can't) then you also would not be able to identify the original from the copy. This is basically a tautology.

It's not just a tautology, it probably made Amanda Gefter a lot of money.

Nobody's making a lot of money writing articles for Nautilus.

A tootology even.

Related: integers do not have identity [0] but objects that have reference semantics have identity.

[0]: https://cs.stackexchange.com/questions/60549

If something has a property it has identity. Our particles have properties that differ them from other particles. I think the real issue is that we haven't discovered all of the properties.

Reply on news.ycombinator.com