What is data compression?

Data compression is a concept in personal epistemology: Categories reduce complexity by treating similar things as equivalent for a given purpose.

Example: A hospital emergency department triages patients into five categories: resuscitation, emergency, urgent, semi-urgent, non-urgent. Each patient is unique — different symptoms, histories, pain tolerances, comorbidities. But the triage system compresses all of that into five buckets that determine who gets seen first. That compression loses detail (the patient's full story) but gains something critical: the ability to allocate scarce resources without drowning in case-by-case analysis of 200 people in the waiting room.

This concept is part of Phase 12 (Classification and Typing) in the How to Think curriculum, which builds the epistemic infrastructure for classification and typing.