“The System You Deployed Is Not the System You Designed” by Thane Ruthenis

tl;dr: Novel framing on the trivial point that your models may not be accounting for all relevant factors. I find it useful for improving the quality of my thinking on the topic. Asking yourself "is the type signature of my design for achieving X actually 'a design for achieving X'?"[1] is a good prompt for checking which parts of your model you have uneasy doubts about, in your heart of hearts.

Illustrative Examples

1. In acoustics, there's something called the RESWING effect. Suppose you want to decrease noise in some area, so you surround it with soundwalls. Your model is simple: separating contiguous chunks of air by hard barriers impedes interactions between those chunks, which should impede sound propagation.

One factor turns out to foil this plan: in atmosphere, the sound speed isn't fixed. It increases with height, due to generally higher wind speeds and temperature differences. This causes [...]

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Outline:

(00:34) Illustrative Examples

(03:53) Abstract Generalization

(05:57) Practical Advice

The original text contained 2 footnotes which were omitted from this narration.

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First published:

September 5th, 2025

Source:

https://www.lesswrong.com/posts/NQfeEd5LWohauKpTj/the-system-you-deployed-is-not-the-system-you-designed

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Narrated by TYPE III AUDIO.