Abstract
Whether properties lacking a quantitative structure can be meaningfully measured is a subject of debate in measurement science. In particular, the metrological status of classificatory properties is not fully established yet, and existing positions diverge significantly, ranging from restrictive definitions that limit measurement to quantitative properties to more inclusive views that also admit qualitative ones. It is proposed here to characterize measurement not by the algebraic structure of the evaluated properties or the information produced, but rather through publicly and explicitly justified epistemic conditions, as usually conveyed in terms of measurement uncertainty. A preliminary distinction is made between types of empirical properties and types of scales, where a scale is understood as a representation of the empirical structure known of a property. On this basis, classificatory properties are characterized not as merely "nominal" properties, but as properties whose instances are partitionable into empirically justified equivalence classes. It is then shown that classificatory evaluations can satisfy the same epistemic requirements as measurements - as traditionally intended - despite conveying structurally weaker information. This perspective supports the development of a unified framework in which the distinction between "strongly defined" and "weakly defined" measurement reflects differences only in the structural richness of the produced information, rather than in its trustworthiness.