Linking Theory and Data in the Scientific Study of Constructs and Individual Measurements

Abstract

This chapter discusses how the quantitative vision is applied in traditional science and its complex implications for the work of the local clinical scientist. Central to this vision is an attitude about the scientific importance of part-whole relationships—as between individual and the collective—methodologically expressed in the belief that aggregation sheds light on general scientific phenomena. Data from collections of cases are analyzed to examine higher-order principles that might underlie the similarities or differences observed, as defined in terms of relationships between variables. The individual case and all other aspects of specificity in science are construed as instances of the combined outcome (main effects and interactions) of general forces in nature. Direct observation of aggregates is required to achieve nomothetic, or truly general, knowledge that is reliable and valid. It is assumed that this knowledge is often difficult to view clearly in the individual case. This may be because of the prominence of error, or because lawful effects are small and only discernible when their incremental and systematic impacts can accumulate with the combining of cases relative to the random and relatively limited impacts of error.

... what is chance for the ignorant is no longer chance for the learned. Chance is only the measure of our ignorance. Fortuitous phenomena are, by definition, those whose laws we are ignorant of.

—Poincaré (1952, p. 65)