As I mentioned at the top of the story, this is based on a post by foone, which describes a setting from some of her dreams which is a copy of the real world but with no people and various other weird, creepy things going on. One of the details that stood out to me was that fires are harder to start, which, together with electricity not working, seems to suggest to me a change in the laws of physics. Specifically, at least to me as someone who knows something about physics but isn't a physicist, it seems like maybe electrons are binding more tightly to atoms, making chemical reactions harder to start (which would also prevent most life from surviving).
Some things I've decided about this particular interpretation of the Empty World:
This story was also inspired by some fears I had at one point in my life, which I mention on my page about derealization. It's actually a combination of a couple related fears; one is a fear of the laws of physics changing in various ways.
The other is basically the realization that the main character had at the end: If Many Worlds is true, at least if I'm understanding it correctly, every random quantum event causes the universe to split, which means both possible outcomes are actually happening. That includes extremely unlikely events, things that we consider basically impossible. I remember my high school physics teacher saying that there's an extremely minuscule chance that if you touch a wall that your hand will go right through, so if I'm understanding all of this correctly, that means that every time I touch a wall I will definitely experience my hand going through it in some universe… and if that happens it'll probably get stuck, which would be very bad. And there's nothing special about hands and walls, so I'm also always falling through the floor.
I wasn't sure exactly how specific I should get with the physics. This is supposed to be a scientist's lab notebook, so it seems weird that I'm not putting down actual numbers and scientific terms and whatnot, but those would be irrelevant to the actual real-life reader, and if I put real numbers and physics then I could end up being actually wrong about something. I also kind of didn't want to just make something up—
Wait, no. I've changed my mind. I changed "rest mass of an electron" to the "Onistu parameter". This also gets me more use out of the name. (I've already posted this on Tumblr, so that version doesn't get the change.) I specified that it affects the rest mass, but at least this way I don't have to worry about how plausible the specific number I gave is.
Anyhow, I tried to figure out which constant should vary. Fine structure constant would be a well-known dimensionless quantity, and apparently there have been suggestions that it's varied in the past, but I don't understand it well enough (and reading Wikipedia didn't make it clear enough to me) whether this would have the effects I wanted, and whether it should go up or down. Permittivity of free space seems relevant, but I don't know if it has a particular value by definition. Rest mass of an electron does seem to affect ionization energy, which seems like what I want, and is something I kind of understand (and the ratio of rest masses of the fundamental particles is dimensionless), so that's what I originally went with.
I also initially had the debris be concrete (because the debris are the building falling apart), but I wasn't sure if concrete could plausibly burn if the universal constants were different such that everything burns more easily, so I just went with wood instead (which I know burns). The debris are supposed to be bits of the lab falling apart, and there's probably wood somewhere, at least.
This is set in the far future so that there could be whatever advances in physics are needed to build this world machine, and to measure universal constants more accurately. I didn't really make any big changes to technology, since I didn't want to distract from the main point and didn't want to do the worldbuilding, but the "deskphone" is a future desktop computer (people started calling them that because smartphones were more familiar, and/or there was some major redesign at some point based on smartphones), but phones can now switch between carriers more easily. Satellite phones are now common enough that they've shorted it to "sat". They've somehow figured out a way to harness the strong nuclear force for energy ("gluonic power plants") and abandoned fossil fuels. Also apparently lab notebooks, at least in some labs, still use pen and paper in this future.
I came up with Dr. Onistu's name by keysmashing (in Dvorak on the home row, to get common letters) and then editing it until it looked good. I decided to give them a name because they were originally going to have a larger role in the story (the main character was going to get equipment directly from them, rather than from people in their own lab).