A CRITIQUE OF A MEASUREMENT-THEORETIC CRITIQUE - COMMENTARY ON MICHELL, QUANTITATIVE SCIENCE AND THE DEFINITION OF MEASUREMENT IN PSYCHOLOGY

Over the past 40 years there has been much theoretical progress in the understanding of what it means to make measurements. If numbers are a ssigned to objects. or events, the kinds of arithmetical operations (s uch as averaging or calculating ratios) which it is thereafter meaning ful to carry out on the numbers depend on the rule of assignment. Meas urement theory, roughly speaking, is concerned to identify what condit ions need to be satisfied to make this or that arithmetical operation meaningful. Measurement theorists, generally, feel that psychologists have disregarded their work, to tie detriment of the development of ps ychology as a natural science. Michell's article is a polemic-a very s cholarly and well-argued polemic-addressing this issue. It would have helped his argument, however, to have explained why measurement theory should matter to psychologists, and I endeavour, first of all, to rem edy that deficit.