Ground every abstraction with 3+ examples from different domains — single examples overgeneralize

Why This Is a Rule

An abstract concept linked to a single example becomes fused with that example's surface features. "Feedback loop" linked only to a thermostat example makes the concept feel like it's about temperature control. Linked to three examples — thermostat (temperature), compound interest (finance), and team morale spirals (management) — the concept detaches from any single domain and becomes a structural pattern: output influencing input.

Gentner's structure-mapping research confirms that learning from single examples produces surface-feature transfer (you apply the concept when surface features match) while learning from multiple diverse examples produces structural transfer (you apply the concept when the structural pattern matches, regardless of surface features). Three diverse examples is the minimum for reliable structural transfer.

In a knowledge system, this means every abstract concept note should be linked to at least three concrete example notes from different domains. The examples serve dual purpose: they ground retrieval (you find the concept when encountering similar examples) and they deepen understanding (the structural pattern is visible only in the intersection of diverse examples).

When This Fires

• Adding an abstract concept note to your knowledge system
• Reviewing concept notes that feel vague or hard to apply
• When a concept seems clear in one domain but you can't apply it elsewhere
• Complements Test understanding by generating three examples from different domains — vocabulary is not comprehension (three-domain example test for understanding verification)

Common Failure Mode

Three examples from the same domain: "feedback loop in software: CI pipeline, monitoring alerts, A/B test iterations." These all share software surface features, so the abstraction remains domain-bound. The fix: one software example, one biological example, one organizational example. The diversity forces the structural pattern to surface.

The Protocol

For each abstract concept in your system: (1) Check: how many concrete examples are linked? From how many domains? (2) If fewer than three from different domains → add examples. Ask: "Where else does this structural pattern appear?" (3) Each example should instantiate the concept's core mechanism in a different domain. (4) The concept note becomes the hub; the examples become the spokes. Future retrieval works through any spoke, and understanding deepens at the hub where diverse spokes converge.