Measurability, systematic error, and the replication crisis: A reply to Michell (2019) and Krantz and Wallsten (2019)

Although Krantz and Wallsten (2019) claim that interval and ratio scales abound in psychology, they miss the opportunity to deliver specific evidence for their existence. Michell (2019), on the other hand, misconstrues my objection against the practical usefulness of conjoint measurement (Trendler, 2019). Furthermore, he underestimates the critical role humans play as measurement instruments—that is, as detectors of magnitudes of psychological attributes as derived quantities—and he also misunderstands the meaning of the Millean Quantity Objection. Finally, in answer to Krantz and Wallsten, I specify my position with regard to the connection between scientific stagnation, measurability, and reproducibility