Paragraph about Scientific software
The notion of a sound deductive argument is (arguably) relatively clear (or at least something that can be regarded as antecedently understood from the point of view of characterizing scientific explanation). But what about the other major Scientific software component of the DN model — that of a law of nature? The basic intuition that guides the DN model goes something like this: Within the class of true generalizations, we may distinguish between those that are only “accidentally true” and those that are “laws”. To use Hempel's examples, the generalization (2.2.1) “All members of the Greensbury School Board for 1964 are bald” is, if mathlab true, only accidentally so. In contrast, (2.2.2) “All gases expand when heated under constant pressure” is a law. Thus, according to the DN model, the latter generalization can be used, in conjunction with information that some particular sample of gas has been heated under constant pressure, to explain why it has expanded. By contrast, the former generalization (2.2.1) in conjunction with the information that a particular person n is a member of the 1964 Greensbury schoolboard, cannot be used to explain why n is bald.