Hanlon's Razor

Biological Parallel

Most apparent attacks are accidents. Immune systems must distinguish intentional pathogens from benign exposures to avoid autoimmune disorders where the body attacks itself. Type 1 diabetes results from immune cells mistaking pancreatic beta cells for threats—malice attributed to incompetence. The immune system lacks perfect discrimination; errors default to caution, but excessive caution destroys the organism. Plant-herbivore interactions demonstrate the same principle. When a caterpillar chews a leaf, the plant triggers defenses—releasing toxins, signaling nearby plants, attracting predatory wasps. But mechanical damage from wind produces identical chemical signals. Plants can't perfectly distinguish malicious herbivory from accidental damage. Hanlon's Razor would counsel: assume wind until evidence proves otherwise. But plants evolved to assume malice because the cost of ignoring real herbivory exceeds the cost of false alarms. The evolutionary stable strategy inverts Hanlon's Razor when attack costs exceed defense costs. Microbial ecosystems show the complexity. When bacteria release antibiotics, neighboring microbes experience growth inhibition. Is this intentional chemical warfare or accidental metabolic byproduct? Penicillin production by Penicillium fungi could be deliberate competition or simply waste disposal that happens to inhibit bacteria. The receiving organism can't distinguish intent from incompetence—only effects matter. Attribution is metabolically expensive; response is what matters. Hanlon's Razor is a cognitive heuristic for social organisms with theory of mind. But biology operates without intent attribution. A tree doesn't ask whether the beetle 'meant' to bore into its bark. It mobilizes defenses or doesn't. The principle fails in biology because natural selection optimizes for outcomes, not intentions. Never attribute to malice what adequacy explains by incompetence assumes malice and incompetence are distinguishable categories. In biology, they're not.