Here’s a pattern I’d like to be able to talk about. It might be known under a certain name somewhere, but if it is, I don’t know it. I call it a Spaghetti Tower. It shows up in large complex systems that are built haphazardly.

Someone or somethdesidesigning builds the first Part A.

Later, someone wants to put a second Part B on top of Part A, either out of convenience (a common function, just somewhere to put it) or as a refinement to Part A.

Now, suppose you want to tweak Part A. If you do that, you might break Part B, since it interacts with bits of Part A. So you might instead build Part C on top of the previous ones.

And by the time your system looks like this, it’s much harder to tell what changes you can make to an earlier part without crashing some component, so you’re basically relegated to throwing another part on top of the pile.

I call these spaghetti towers for two reasons: One, because they tend to quickly take on circuitous knotty tangled structures, like what programmers call “spaghetti code”. (Part of the problem with spaghetti code is that it can lead to spaghetti towers.)

Especially since they’re usually interwoven in multiple dimensions, and thus look more like this:

Second, because shortsightedness in the design process is a crucial part of spaghetti machines. In order to design a spaghetti system, you throw spaghetti against a wall and see if it sticks. Then, when you want to add another part, you throw more spaghetti until it sticks to that spaghetti. And later, you throw more spaghetti. So it goes. And if you decide that you want to tweak the bottom layer to make it a little more useful – which you might want to do because, say, it was built out of spaghetti – without damaging the next layers of gummy partially-dried spaghetti, well then, good luck.

Note that all systems have load-bearing, structural pieces. This does not make them spaghetti towers. The distinction about spaghetti towers is that they have a lot of shoddily-built structural components that are completely unintentional. A bridge has major load-bearing components – they’re pretty obvious, strong, elegant, and efficiently support the rest of the structure. A spaghetti tower is more like this.

Where do spaghetti towers appear?

Basically all of biology works like this. Absolutely all of evolution is made by throwing spaghetti against walls and seeing what sticks. (More accurately, throwing nucleic acid against harsh reality and seeing what successfully makes more nucleic acid.) We are 3.5 billion years of hacks in fragile trench coats. Scott Star Codex describes the phenomenon in neurotransmitters, but it’s true for all of molecular biology:



You know those stories about clueless old people who get to their Gmail account by typing “Google” into Bing, clicking on Google in the Bing search results, typing “Gmail” into Google, and then clicking on Gmail in the Google search results? I am reading about serotonin transmission now, and everything in the human brain works on this principle. If your brain needs to downregulate a neurotransmitter, it’ll start by upregulating a completely different neurotransmitter, which upregulates the first neurotransmitter, which hits autoreceptors that downregulate the first neurotransmitter, which then cancel the upregulation, and eventually the neurotransmitter gets downregulated. Meanwhile, my patients are all like “How come this drug that was supposed to cure my depression is giving me vision problems?” and at least on some level the answer is “how come when Bing is down your grandfather can’t access Gmail?

My programming friends tell me that spaghetti towers are near-universal in the codebases of large companies. Where it would theoretically be nice if every function was neatly ordered, but actually, the thing you’re working on has three different dependencies, two of which are unmaintained and were abandoned when the guy who built them went to work at Google, and you can never be 100% certain that your code tweak won’t crash the site.

I think this also explains some of why bureaucracies look and act the way they do, and are so hard to change.

I think there are probably a lot of examples of spaghetti towers, and they probably have big ramifications for things like, for instance, what systems evolution can and can’t build.

I want to do a much deeper and more thoughtful analysis about what exactly the implications here are, but this has been kicking around my brain for long enough and all I want to do is get the concept out there.

Does this feel like a meaningful concept? Where do you see spaghetti towers?

Crossposted to LessWrong.

Happy solstice from Eukaryote Writes Blog. Here’s a playlist for you (or listen to Raymond Arnold’s Secular Solstice music.)