doi:10.1093/pq/pqag008 The Philosophical Quarterly Text journal article © The Author(s) 2026 open access 2026 Martin Niederl Zsófia Virányi (Messerli Research Institute of Human Animal Interactions, Department of Interdisciplinary Life Sciences, Departments, University of Veterinary Medicine Vienna) Oxford University Press Documento PDF Articolo scientifico http://creativecommons.org/licenses/by/4.0/ application/pdf Rationality Non-human Animals Animal Agency Higher-order Reasons Animal Reason Comparative Psychology Animal rationality through higher-order reasons Melis and Monsó have recently argued that non-human animals are capable of reflectively responding to normative reasons. They argue for this via animals’ capacity to respond to undermining epistemic defeaters. Although we are ultimately sympathetic to this idea, the present article develops a principled methodological challenge to the empirical evidence they cite to corroborate their claims. What we call the Acquisition Problem shows that the studies that Melis and Monsó cite cannot provide differential support for the hypothesis that animals reflectively respond to reasons. We close by suggesting two possible ways forward that evade our challenge, while remaining true to the spirit of Melis and Monsó’s proposal. First, future studies could aim to model testimony of undermining defeaters in social learning. Second, and even more promisingly, we should focus on the broader phenomenon that Melis and Monsó’s proposal points towards, namely, animals’ responsiveness to higher-order reasons. Open Access Text Wissenschaftlicher Artikel eng https://phaidra.vetmeduni.ac.at/o:5425