Systems, Observables, and States
BEFORE ENTERING upon the substance of the present chapter, which is done in the next section, we turn briefly to the question above, which will raise its head annoyingly throughout our work unless it is partially dealt with beforehand.
Whether science "describes" or "explains" phenomena is a problem we are not prepared to consider fully at this point. Only preliminary comments for the purpose of orientation will be made. To settle the problem one must first of all expose what is to be described or explained. Since our concern is experience, and not a presumed reality, a crucial occasion for this discussion has not yet arisen. And its solution is likely to be obvious when reality has been crystallized from the matrix of experience.
Reserving, then, our final judgment on this problem, we nevertheless recognize that the distinction between explanation and description is a genuine one in scientific discourse; some theories are de facto said to describe, others to explain. The former are often called phenomenological, the latter causal theories. We have already met a similar kind of division, namely, that between correlational and exact (or deductive) theories; and the difference here under consideration might for reasons of precision be identified with it. But somehow this does violence to the suggestion of polarity carried by the words explanation, description, and the identification is in fact not quite correct.
For while it is clear that all correlational sciences are descriptive (even though correlations might be established between factors which in another interpretation can be looked upon as cause and effect), the exact sciences also contain theories which describe rather than explain, as for instance the following: