A relatively demanding form of understanding is of central interest in science and philosophy. We strive to understand climate change through climate models, issues in medical ethics by means of a system of ethical principles, or a nancial crisis with the help of economic theories. In all these examples, we seek not only a single explanation of a phenomenon, but strive to understand a subject matter (or “domain” or “topic”) by means of a theory. This we call “objectual understanding.”1