What is portable knowledge?

Portable knowledge is a concept in personal epistemology: Filing systems come and go but a well-linked graph retains its value regardless of how you browse it.

Example: Niklas Luhmann's Zettelkasten — 90,000 paper slips linked by a numbering system he invented in the early 1950s — survived his death in 1998, was purchased by the University of Bielefeld, digitized, and published online in 2019. The slips were written in a format any literate person can read: handwritten German on index cards. The linking system — branching alphanumeric IDs like 21/3a1p5c4fB — required no software, no database, no proprietary viewer. Sixty-seven years after the first card was filed, the entire graph was migrated to a digital medium without losing a single connection. The tool changed. The graph persisted.

This concept is part of Phase 18 (Knowledge Graphs) in the How to Think curriculum, which builds the epistemic infrastructure for knowledge graphs.