Know when not to apply the razor

Occam’s Razor is a tiebreaker, not a rule: when evidence clearly supports complexity, go there.

Why it works

The razor is a prior preference, applicable when two explanations fit the evidence equally well. When evidence unambiguously requires a more complex explanation — multiple causes, interacting factors — parsimony is the wrong tool. Applying it rigidly misuses it as a thought-stopper rather than a guide for underdetermined situations.

How to do it

1. Check the evidential situation: are both explanations currently supported equally, or has evidence already distinguished them?
2. If evidence supports the complex explanation clearly, update regardless of complexity.
3. Use the razor explicitly as a prior that weakens when evidence accumulates — not as a rule that ignores evidence.
4. Reserve "but the simple explanation is more likely" for underdetermined cases, not for cases where data has spoken.

Evidence

Philosophers of science debate the epistemic status of simplicity as a virtue; the dominant view (Sober, Quine) treats it as a prior preference that yields to evidence. The razor’s value is in underdetermined situations, not against strong evidence. Sober's book-length treatment shows the razor resolves into several distinct principles with different scopes, so its force depends on which one the situation actually calls for. (mechanistic)

This is a philosophical/methodological point; its force is logical rather than empirically derived.

Sources

• Sober, Elliott (2015). Ockham's Razors: A User's Manual. Cambridge University Press.

Common mistake

Using 'simpler is always better' to avoid updating when evidence genuinely demands a more complex picture.