Also known as the covering law model of scientific explanation, it means in effect ‘deduction from laws’. According to the model, put forward by Carl Gustav Hempel (1905-1997) and Paul Oppenheim in 1948, scientific explanations deduce a statement describing a phenomenon to be explained (the explanandum) from a statement (the explanans) specifying a law, or set of laws, and that describing relevant initial conditions. Thus, an explanandum is, according to the model, a deductive consequence of an explanans. The model was designed to capture the main characteristics of explanation in the physical sciences and biology. However, it was never claimed that it could cover all types of scientific explanation (e.g., statistical explanations), but rather that it was an ideal toward which many such explanations could strive to achieve. One striking feature of the model is that it treats explanation and prediction as having the same logical structure (i.e., an explanation can be used to forecast and a forecast is a valid explanans). The only difference between an explanation and a prediction is whether the state of affairs described in the explanandum is known to have been achieved. There are, however, grounds for making this distinction in a more definitive manner. In general, the D-M model has similarities with the hypothetico-deductive method and with Popper‘s model of falsification.
See Bridge law (or principle), Deduction, Explanans and explanandum, Explanation, Law, Hypothetico-deductive method, Laws of nature, Logical reasoning, Prediction and explanation