January 24, 2026

“Condensation & Relevance” by abramdemski

8 minutes

(This post elaborates on a few ideas from my review of Sam Eisenstat's Condensation: a theory of concepts. It should be somewhat readable on its own but doesn't fully explain what condensation is on its own; for that, see my review or Sam's paper. The post came out of conversations with Sam.)

As I mentioned in my Condensation review, the difference between compression and condensation fits the physical analogy suggested by their names: compression mashes all the information together, while condensation (still compresses size, but) sorts information into discrete droplets.

Thus, condensation has a property we might call local relevance: typical questions can be answered at a glance, ie, retrieving small subsets of the information. This type of representation is sometimes called "symbolic":

SymbolicNot SymbolicA number can be quickly determined positive or negative by checking whether there is a "-" symbol in front."reading the room" at a social gathering requires integrating diverse cues.The topic of a paper can be determined by reading the title and abstract.The semantic content in a vector representation inside an artificial neural network is often represented redundantly, spread across the whole vector.A person's age can be determined by looking at their birthdate on a government-issued ID.The [...]

The original text contained 3 footnotes which were omitted from this narration.

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First published:

January 23rd, 2026

Source:

https://www.lesswrong.com/posts/2x9yatKKTRMabQAWq/condensation-and-relevance

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Narrated by TYPE III AUDIO.

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