How I Explain Quantum Weirdness to a Friend

*Lincoln Park, Jersey City, a perfect setting for a chat about quantum weirdness.*

JERSEY CITY, MAY 31, 2025. I’m still a little confused about quantum mechanics, why everyone thinks it’s so weird. Can you explain that again, Horgan?

Vicki asks this question as we sit on a bench in Jersey City’s Lincoln Park, watching our fellow humans play soccer, ride bikes, loll on the grass. Having fun as though everything is okay. She seems serious.

I begin with obligatory false modesty: I’m just a journalist not a physicist, and no one really understands quantum mechanics blah blah blah. Then I say something like the following (tweaked to make me sound better):

Okay, to understand what makes quantum mechanics so weird, you need to know what physics was like before it. The old physics has equations that tell you exactly what happens to an object if you apply a force to it.

Vicki: What do you mean by an object? And a force? Give me examples.

Oh, an object can be anything. A car, a rocket, a baseball, a spaceship, a moon. Let’s say you have a rock just sitting here, not moving. You apply a force to it, which just means you throw it in the air. Or you shove it and keep shoving it. Or you drop it from a tree. Or you blow up gunpowder under it. Whatever.

If you know the weight of the rock, and the strength of the force acting on it, the equations of the old physics tell you exactly how fast the rock moves and where it goes.

Vicki: Why does anyone want to know that?

Well, knowing where things go can be useful. Like for example, you want to know where a cannonball goes when you shoot it in the air, so it lands on your enemy and kills him.

Vicki: Nice example, Mr. No More War!

Killing people has always been a big part of physics. Now the old physics can get really complicated, you might need lots of equations to calculate friction and air resistance and stuff like that, but that’s the basic idea. The old physics, ideally, in principle, tells you exactly where the cannonball or whatever is at any moment.

And quantum mechanics doesn’t do that, it doesn’t tell you exactly where something is. The equations of quantum mechanics tell you only where the object might be at a given moment, they give you only probabilities.

Vicki: Wait. Why is quantum mechanics so great if it’s not precise? You make the old physics sound better.

Well, the old physics works really well for lots of things, like predicting eclipses or landing a man on the moon. It just turns out the old physics doesn’t work when it comes to really small things, like electrons and protons, which atoms are made of.

Quantum mechanics, even though it’s based on probabilities, works really well when it comes to tiny things like electrons and protons. It predicts the results of experiments with amazing accuracy. And it’s led to all sorts of useful inventions, like lasers and computer chips and hydrogen bombs.

But quantum mechanics makes no sense, because of the probability thing. So for example, quantum mechanics might tell you there’s a 50 percent probability an electron will be here at this moment, and a 50 percent probability it’ll be there. (I move my finger back and forth to indicate two spots.)

You can only know for sure where the electron is by looking at it, like with a detector. Then maybe you see the electron ended up here. Now common sense would tell you the electron was here before you looked. I mean, you know a cannonball is in one place whether or not you’re looking at it. And the same must be true of the electron, right?

Vicki: I guess so.

But here’s what’s weird. If you assume the electron is in just one place before you look, you get results that don’t agree with experiments. That’s why some physicists say the electron must somehow be in two places at the same time before you look. You’ve heard of that, right? The two places at the same time thing? [See Addendum.]

Vicki: Yes, that’s definitely weird.

Yup. Physicists have gone nuts trying to explain how something can be in two places at the same time. You’ve probably heard of the many-worlds theory. It says the electron is in two places at the same time, here and there, but in different universes! So if we look at the electron and find it here in our universe, that means it’s there in another universe that branched off our universe.

Vicki: Yes, I’ve heard of that, parallel universes, I love it, that’s amazing.

Mm, yeah, I don’t like the many-worlds theory.

Vicki: Why not? Wouldn’t it be cool if there are other universes?

I like many-worlds as a premise for science fiction, like that movie Everything Everywhere All at Once. But I don’t like it as a scientific theory, because it’s pure speculation, it’s not science. Physicists have no way of knowing whether those other universes exist or not.

Vicki: That’s too bad.

I don’t like other explanations of quantum mechanics either. There’s one called superdeterminism, which says everything we do is fated from the beginning of time. I didn’t choose to look at the electron and find it here. You and I didn’t choose to be here in this park having this conversation. Free will does not exist. Well, fuck that, fuck superdeterminism, I hate it.

Vicki: Yes, I know you believe in free will, sweetie.

Yes, I do, schmoopie. But my point is that none of the attempts to explain away quantum weirdness works, they all suck. So I’ve decided there is no explanation. Quantum mechanics is just a bunch of equations that work in specific situations. That’s true of the old physics too. None of these mathematical theories, old or new, can really explain you and me and all this. (I wave my arm at the park and people around us.)

Vicki: Oh, I know, Horgan, because it’s all a mystery.

Yeah, physics can explain a lot, but there’s a lot it can’t explain, and will never explain.

Vicki: That’s fine, I like mysteries too. I’m getting hungry. You want to go home now? Let’s go home. I’ll make something for dinner.

Sounds good. I’m feeling lazy, wanna take an Uber?

Vicki: Of course!

My iPhone shows me the exact location of an Uber car, four minutes away. We start walking toward the pick-up point past people who like us are made of electrons and protons and possess free will and are still chilling as though everything is okay.

Addendum: Astrobiologist David Grinspoon points out on Facebook that in 1969 the comedy troupe Firesign Theatre (to whom I alluded in my column on Gravity’s Rainbow) released the album “How Can You Be in Two Places at Once When You’re Not Anywhere At All.”

*When I was in high school, I had friends who, while high on weed, could recite long passages from this album.*

Further Reading:

See my free online book My Quantum Experiment for more on quantum mechanics, including the math (calculus, linear algebra, imaginary numbers) underlying quantum weirdness.

Sabine Hossenfelder critiques a quantum interpretation based on cellular automatons in this typically clear, concise video.

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