Deductive-nomological model

The D-N model is a formalisation of natural language explanations. The model sets a form for a scientific explanation that is similar to that of a sum or calculation:

[S] (Explanans) [P] (Explanandum)

Contained within [P] are sets of statements which describe the phenomenon to be explained. They are given the name ‘explanandum’ and provide a description of the phenomena. Contained within [S] are a number of statements that ‘explain’ the statements in [P]. Amongst the statements in [S] must be at least one statement of a very specific type. There must be one statement which is in general ‘law-like’ or general. Some statement of the form: All Fs are Gs. The final consideration of form pertains to the relation between the explanans [S] and the explanandum [P]. This relation is one of logical entailment. Which is to say given the set of explanans statements [S], it must be possible to deduce the explanandum [P].