The ArgumentBiology, understood in turn-of-the-century Germany to include psychology, held a central but enigmatic place in the philosopher Ernst Cassirer's work. From his earliest studies with Hermann Cohen through his long engagement with the theoretical biology of Jakob von Uexküll and Adolf Meyer-Abich, Cassirer consistently used the history and practice of biology to examine and delineate a set of characteristic tensions between the natural and cultural sciences. This paper examines Cassirer's treatment of this theme by addressing two contrasting interpretations he (...) gave — in hisPhilosophy of Symbolic Forms and in hisEssay on Man — to the benchmark case from empirical psychology of the “talking” horse “Clever Hans.” The original case involved the horse's ability to signal answers to remarkably complex questions by stamping its hooves, an ability that ultimately appeared to rest on a capacity to detect extremely minute unintentional movement cues in its auditors as it reached the appropriate answer. Due to both Cassirer's shifting description of the case within his philosophy and the case's inherent polyvalence, Cassirer's remarks provide a useful window onto the social, epistemological, and stylistic meaning of his “unified” philosophy of human culture and science. (shrink)