The Universe is a Sheet of Paper (and Some Sand)

Ted Hayes

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The Universe is a Sheet of Paper (and Some Sand)<br>Or: making the weird shit about quantum physics very slightly less weird

Ted Hayes<br>May 26, 2026

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A piece of paper<br>Imagine a sheet of paper. It has two sides.<br>With me so far?<br>It’s not surprising that it has two sides, in fact you couldn’t call it a sheet of paper if it didn’t have two sides. Having two sides is in the nature of a sheet of paper.<br>Now say the paper is opaque. The writing on one side can’t be seen on the other side. Whatever you do on one side can never be “influenced” by what’s on the other side, because you can’t see it.<br>Suppose the paper is slightly transparent. You could, for instance, move a pen around on one side, leaving a mark, and the pen on the other side could follow that mark.<br>Believe it or not, we’ve just described the following seemingly wacky and famously difficult concepts:<br>Quantum superposition

Entanglement

“Many Worlds”

Orthogonality

Coherence & decoherence

Interference

The goddamn double slit experiment

One at a time:<br>Superposition

The sheet of paper can certainly be said to have two sides, but you don’t have to say “a thing with two sides glued to each other,” because you can just say “a sheet of paper.”<br>Similarly, when you view the universe as one single thing, you can say it has lots of states, and sometimes those states can interact easily, and sometimes it’s very hard for them to interact.<br>When you say a coin flip can result in heads or tails, you don’t say “a heads-tails object,” you just say a coin. The coin is the actual underlying thing, not the results of flipping it. Furthermore, it’s not strange that there’s a 50% probability of heads or tails, it’s simply a fact of the thing having two sides.<br>Entanglement

This is the big bad boy, the one that every motherfucking journalist apparently ever calls “spooky action at a distance,” and I 100% guarantee you Einstein would go back in time and shoot himself before he ever said that just to prevent anyone else from ever repeating it.<br>Anyway, entanglement is when you’re able to follow the pen on the other side of the paper. Entanglement says “the marks on both sides of the paper constitute the whole paper.” That’s it. Yes, really. If you introduced another, separate sheet of paper, it’s possible their marks don’t have anything to do with each other, and you’d say they are not entangled with each other.<br>Another way of saying this: in order to describe the whole piece of paper, you must describe what’s on both sides of it. That means the two sides are entangled with each other.<br>If you take away only one thing from this unhinged, oversimplified rant, make it that entanglement is not a weird, unexpected connection between things. Entanglement is ordinary. Things NOT being connected is actually the much weirder, hard-to-imagine phenomenon.<br>“Many Worlds”

Like many, I bet, Sean Carroll got me into Everettian quantum mechanics, often referred to as “Many Worlds,” because it’s what you get when you “take the math at face value,” so to speak.<br>So say you start off with a slightly translucent sheet of paper. Your marks on one side can be informed or affected by marks on the other side.<br>Then the sheet of paper becomes opaque, or least opaque enough where you can no longer see anything on the other side.<br>This is what is commonly thought of as “branching universes.” But you didn’t branch anything, you just can’t see the other side of the paper any more. That doesn’t mean your side is the only side that exists, or ever existed. The sheet of paper has always been there and its other side will go on doing whatever it does.<br>Orthogonality

Those two independent sides are “orthogonal” to each other.<br>Look at a simple x-y chart. The reason we say the x-axis is “orthogonal” to the y-axis is because you only need one axis to describe a point on that axis.

If you want to describe a point on the plane, you need at least two axes.<br>These axes are also called:<br>Dimensions

Degrees of Freedom

So when a “world” or “universe” or “branch” is orthogonal to another one, it means they are independently describable, and further, that you cannot provide any information about one world with another orthoganal world.<br>Coherence & Decoherence

Following from the previous example, the translucent sheet of paper is in a “coherent” state, and “decoherence” is the process of the other side of the paper becoming unable to affect your side.<br>Let’s take this a bit further. When you make a mark on your side of the paper, the other side can see it and react to it. But the paper fibers move slightly, which themselves affect other nearby marks on both sides of the paper. Tiny wrinkles and cracks start to appear in the paper. The ink bleeds nearly imperceptibly.<br>The information in your mark is no longer just in the mark you made: it has spread out in ways you aren’t thinking about or aware of. And in order to describe the whole mark,...