Before revision: In scientific method Carl Gustav Hempel and Paul Oppenheim (1948), in their deductive-nomological model of scientific explanation, motivated the distinction between explanans and explanandum in order to answer why-questions, rather than simply what-questions: Specifically, they define the concepts as follows: The crucial comment, with respect to the scientific method, is given as follows: In biological systematicsPhilosopher of science Ronald Brady proposed that the pattern of relationships among organisms represents an explanandum that is prior to and independent of its explanation (explanans), the theory of evolution.
After revision: Carl Gustav Hempel and Paul Oppenheim (1948), in their deductive-nomological model of scientific explanation, motivated the distinction between explanans and explanandum in order to answer why-questions, rather than simply what-questions: The crucial comment, with respect to the scientific method, is given as follows: In biological systematicsPhilosopher of science Ronald Brady proposed that the pattern of relationships among organisms represents an explanandum that is prior to and independent of its explanation (explanans), the theory of evolution.