Qianru Wang

Evidence-based policy often involves a kind of reasoning by analogy, which starts from the established success of an intervention on a given occasion (= source domain S). Policy makers infer that the same intervention is likely to be successful on another occasion (= target domain T). The practical goal of this paper is to develop, defend and illustrate a model detailing the reasoning steps that policy makers should go through in order to perform this type of analogical reasoning properly. Our model also offers tools for diagnosing flaws in the reasoning process for past cases where this kind of analogical reasoning went wrong. We illustrate the practical utility and diagnostic power of the model by means of two well-known failed evidence transfers. The theoretical goal of this paper is to investigate the ramifications of our model for general theorising on analogical reasoning.

Casuistry, which involves analogical reasoning, is a popular methodological approach in bioethics. The method has its advantages and challenges, which are widely acknowledged. Meta-philosophical reflection on exactly how bioethical casuistry works and how the challenges can be addressed is limited. In this paper we propose a framework for structuring casuistry and analogical reasoning in bioethics. The framework is developed by incorporating theories and insights from the philosophy of science: Mary Hesse’s ideas on horizontal and vertical relations in analogical reasoning in the sciences, Paul Bartha’s articulation model of analogical reasoning and Daniel Steel’s insights on mechanism-based extrapolation in biomedical research. Adopting our framework results in two practical benefits: it sets methodological standards for analogical reasoning and enables us to compare and evaluate diverging lines of analogical reasoning in a systematic way. Adopting the framework also has theoretical benefits: it helps to understand how analogical reasoning can have moral normativity; it pinpoints exactly where moral principles or theories enter analogical reasoning; and it helps to understand why casuistry is an attractive method in bioethics and in applied ethics more generally.