How precaution should track uncertainty in animal sentience judgements

Debates about animal sentience often appeal to precaution: where the evidence of sentience is strong enough, taxa should be treated as sentient in law and policy. I argue that what is called ‘evidence of sentience’ in fact has two dimensions—robustness of indicators and credibility of the indicator–sentience link—and that standard, threshold-based formulations of precaution ignore this structure. Using a simple model, I show that conjunctive high-threshold rules are over-conservative and excessively fragile, and I sketch an inverse-threshold-with-floors principle better suited to sentience policy.