The history of psychometrics has one constant: the enthusiastic development of means for measuring various kinds of mental performance (to which I will refer simply as measurement of mind) is accompanied by a shadowlike critique that is no less forceful. In the mid-19th century, when Gustav Theodor Fechner-following on from Johann Friedrich Herbart and Ernst Heinrich Weber-presented the idea of psychophysics with great verve, he often met with vehement rejection alongside widespread approval. Critical objections have often been raised on principle, such as that in the domain of the psyche only intensive quantities exist which cannot be measured (see Kant 1956 : B207-218). Another point of critique has been that there is no adequate psychological measure for the psyche. When research on intelligence began around 1900: it very quickly became an area of international research which was rapidly applied in schools, the military, corporations, and psychiatry. To this day, intelligence research has been vehemently criticized, partly because of its alleged dependency on language and culture. Likewise, the measurement of competence, which developed in the 1970s, has also been accompanied by its Siamese twin, critique of the measurement of competence. Most of these critiques originate from the philosophy of science. In the following, I would like to show that this approach is not sufficient. It needs to be supplemented by arguments from the philosophy of technology.