Traditionally Science is concerned with regularities. Thus observations of individual events or occurrences are important only to the extent that the occurrence of such an individual event is the basis for the falsification of a claim about regularities. This attitude pervades the worldview of Science 1.
Within the Science 1 context, the answers to questions of "why?" concern the placement of regularities (observed or conjectured) within an overall schema of regularities. The relevant questions seem to be those of order and of fit. Thus both further descriptions of regularities within an ordered regime (functional explanation) and measurements of adherence to a "pure" (non-contingency messed with) regularity are both offered and accepted as "explanatory". The "how?" question which is implied by the "why?" questions is "how does this fit within the established order?" -- where the answer to "why?" is a mechanism for how fit happens.
Some of the unarticulated assumptions in the
Science 1 worldview are the pre-given-ness of an
established order, the idea that there "should"
be fidelity to that order, that the correct
granularity for inquiry is that at the level of
regularities, and that regularities can be
referred to adequately by labels and
models. Given these
assumptions it is reasonable to eliminate
contingency with a further claim of Ceteris
Paribas, to treat "fit" as measurable, to rely
on noun forms, and to posit "truth" as a
justificatory variable. While each
of these "reasonable" approximations can be
discarded in the pursuit of "better
explanation," our human cognitive limits and our
reliance on the "least action principle" allow
us to simplify "why?' explanations in the
Science 1 world as category membership questions
and allows a pragmatic scientific realism
to guide the articulations of the abbreviated
worldview which results.