Measurement and Mind: Unveiling the Self-Delusion of Metrification in Psychology

This paper critically evaluates the quantification of psychological attributes through metric measurement. Drawing on epistemological considerations by Immanuel Kant, the development of measurement theory in the natural and social sciences is outlined. This includes an examination of Fechner's psychophysical law and the fundamental criticism initially raised by von Kries. The distinction between theoretical and practical measurability is illuminated, addressing the question of equality within mental entities (Ψ) and their measures (θ). Psychometric scaling procedures such as Rasch scaling are argued to enable interval-scaled quantification on a real number line θ, but they are insufficient to establish a genuine interval scale level of Ψ. Instead, the values of θ should be regarded as qualitative statements that indicate ordinal relationships within Ψ. Two principles of scaling – the Guttman "model" and the Rasch model – are introduced, with their theoretical foundations explained, referencing the Rasch paradox. In the empirical section, data simulation is conducted to illustrate the Rasch paradox and to substantiate the theoretical considerations of the article. The research underscores the significance of linguistic analysis in understanding quantitative claims, suggesting a shift toward ordinal quantification within psychological measurement, drawing upon the linguistic principle of localism. Spatial metaphors are argued to play a central role in human language, even in natural sciences like physics, suggesting that systematic analysis of human language could offer a valuable method for the quantitative analysis of psychological attributes.