How do I practice multiple hierarchies?

The most direct way to practice multiple hierarchies is through a focused exercise: Pick a set of fifteen to twenty items you work with regularly — notes, projects, skills, books, contacts, tools. Write them on a list. Now organize them into three completely different hierarchies, each using a different organizing principle. For your notes, try organizing by topic, then by project, then by date. For your books, try organizing by subject, then by author, then by how much they changed your thinking. For each hierarchy, ask: what becomes easy to find? What becomes invisible? Write a paragraph comparing the three hierarchies. Identify the one or two items that move the most — appearing near the top in one hierarchy and buried deep in another. Those items are the ones most sensitive to your choice of organizing principle, and they reveal where your default hierarchy is making implicit priority decisions you may not have intended.

Common pitfall: Hierarchy fixation — treating your current organization as the only possible one. You built a project folder structure organized by client. Now you need to find everything related to "data migration" across all clients, and you cannot, because the client hierarchy buries cross-cutting concerns. You reorganize by capability. Now you cannot find everything for a specific client. The mistake is not choosing the wrong hierarchy. The mistake is choosing one and believing it is the only valid arrangement. Every single hierarchy is a lossy compression of the underlying relationships. When you forget that alternatives exist, you stop noticing what your current hierarchy hides from you — and you start making decisions based on what is easy to see rather than what is actually important.

This practice connects to Phase 14 (Hierarchy and Nesting) — building it as a repeatable habit compounds over time.