Where does purity collide?

The degree to which a material consists of a single substance and is free of other components, usually expressed as the mass fraction of the intended compound present. Proust's 1794 Recherches sur le bleu de Prusse set out the law of definite proportions, that a given pure compound always contains the same elements in the same fixed ratio by mass, which made purity a definite and checkable property, so that any departure from the fixed composition signals contamination. Westwood and colleagues' 2023 IUPAC report Methods for the SI-traceable value assignment of the purity of organic compounds codified how a purity value is measured and traced back to reference standards. The referent is a physical property of matter, counted as a percentage or mass fraction, and it has nothing to do with a moral concern in the mind or a symbolic boundary in a culture.[1][2]

Unit

A single material's content of the intended substance, as a mass fraction or percentage

Recovery means

Restored by purification steps such as distillation, recrystallisation, or chromatography that remove contaminants

Measured by

Determined by analytical assay such as chromatography, quantitative NMR, or mass balance against reference standards

In the study of culture, purity is the symbolic condition of being free from pollution or defilement, and the rules that keep the pure and the impure apart help order a society's categories of the clean and the unclean. Mary Douglas's 1966 book Purity and Danger argued that ideas of dirt and pollution are not really about hygiene but about matter that falls outside a culture's system of classification, so that what a group treats as impure marks the boundaries of its accepted order. The referent is a shared symbolic category maintained by ritual and taboo, described by its place in a classification system, and it is not a measurable property of a chemical sample or a concern scored in one person's moral judgment.[3]

Unit

A symbolic category of the clean set against the polluted within one culture's classification

Recovery means

Restored through rites of cleansing or purification that remove pollution and return a person or thing to the accepted order

Measured by

Described qualitatively through ethnography of a culture's rules of taboo, ritual, and classification

In moral psychology, purity, also labelled sanctity, is one of the proposed moral foundations, a domain of concern about degradation and contamination of the body and the self, often tied to the emotion of disgust and to ideas of elevation and the sacred. Haidt and Joseph's 2004 Intuitive ethics first named purity among a small set of innately prepared foundations from which cultures build their virtues, drawing on earlier work linking disgust to an ethic of divinity. Graham, Haidt, and Nosek's 2009 Liberals and conservatives rely on different sets of moral foundations built the questionnaire that gauges how much weight a person places on this foundation. The referent is a dimension of individual moral concern, measured by self-report survey items, and it is distinct from a chemical mass fraction or a culture's symbolic classification of pollution.[4][5]

Unit

One respondent's weighting of purity concerns relative to the other moral foundations

Recovery means

Not applicable

Measured by

Assessed by self-report instruments such as the Moral Foundations Questionnaire