Issues of Classification

Issues of Classification
In order for a variable or phenomenon to satisfy the criterion of “scientific observability,” it is not enough that more than one scientist be able to see it—it is not even enough that a camera be able to record it. Rather, a variable is only scientifically observable if independent observers can agree on their description of what they have just observed. Thus, while a scientist can photograph facial expressions, they cannot be said to have photographed expressions of emotion unless there is a well-defined specification of which expressions correspond
to each emotion, and independent observers predominantly agree in their assignment of emotions to each photograph. In other words, scientific observability requires well-defined and commonly accepted classification schemes for the observations, sufficient for grouping and comparing such observations, and relating them to general
hypotheses and theories.
Just as different types of variables can have different degrees of observability, different classification schemes will have different degrees of common agreement. Thus, in regular consumer theory, we
States of the World and the State of Decision Theory 21
are much more prone to classify commodities and define preferences in terms of category schemes like {“fruits,” “vegetables,” “grains”} compared
to schemes like {“delicious foods,” “filling foods,” “unpleasant foods”}. Although the latter scheme is in some sense much more directly connected to any given individual’s preferences than the former scheme, the latter scheme cannot be defined independently of the particular consumer being studied. Since foods cannot be classified according to this latter scheme prior to observation of the consumer’s (verbal or choice) behavior, it cannot be used as a classification scheme for independent variables. Categories like “delicious foods,” “unpleasant
foods,” etc. can be defined for dependent variables, however, either on the basis of the consumer’s verbal expressions, or on the basis of their past purchases or consumption behavior. Thus, whether a given classification scheme does or does not satisfy the criterion of scientific observability may well depend upon whether the scheme is intended to be applied to the independent variables or to the dependent variables of a theory.