Schema revisions must generate new predictions, not just…
When adjusting a schema after disconfirming evidence, require the adjustment to generate new testable predictions rather than merely explaining away the original failure.
Why This Is a Rule
Lakatos distinguished between progressive and degenerating research programs. Progressive programs: when evidence disconfirms a prediction, the revision generates novel predictions that can be tested — the program moves forward. Degenerating programs: revisions only explain away past failures without predicting anything new — the program retreats into unfalsifiability.
The same distinction applies to personal schema revision. "My project failed because the market wasn't ready" is a post-hoc explanation that predicts nothing. "My project failed because I didn't validate demand before building — next time I predict that validation will show at least 30% interest before I commit to building" generates a testable prediction. The first revision is degenerating (explains the past, predicts nothing). The second is progressive (explains the past AND predicts the future).
Requiring new predictions from every schema revision prevents the common pattern of accumulating post-hoc explanations without ever updating the schema's predictive power.
When This Fires
- After a schema's prediction fails and you're revising the schema
- When explaining away disconfirming evidence
- During any belief revision where you want to verify the revision is genuinely improving
- When a schema keeps "explaining" failures without preventing them
Common Failure Mode
Revising by adding exceptions: "My schema still works, it just doesn't apply when [the condition that produced the failure]." This protects the schema from the specific failure but generates no new prediction — it's an ad hoc rescue rather than a genuine revision. The test: does the revision predict something it didn't predict before?
The Protocol
After disconfirming evidence triggers schema revision: (1) Revise the schema to account for the failure. (2) From the revised schema, generate at least one new testable prediction: "Given this revision, I now predict [specific outcome] in [specific conditions]." (3) If you can generate a new prediction → progressive revision. The schema is genuinely improving. (4) If you can only explain the past failure without predicting anything new → degenerating revision. The revision is a rescue operation, not an improvement. Go deeper — find the actual flaw rather than patching around it.