The action of disjoining an undifferenciated and interwoven bundle of causal relations, as usually offered by nature, and systematically joining together the cause-effect relations of interest, while controlling disturbing factors, is what the construction of an apparatus essentially consists of. (p. 587)
Trendler, G. (2009). Measurement theory, psychology, and the revolution that cannot happen. Theory & Psychology, 19, 579-599.