The Theory of Dirt


Despite it becoming her most famous saying, the phrase “dirt is matter out of place” was not actually coined by Mary Douglas. Its exact origins are unclear, but the earliest known version appears in the record of an 1853 speech given to the Royal Agricultural Society by Lord Palmerston (who would later go on to be the fifth Prime Minister of the United Kingdom) (Fardon 2013). Nevertheless, “matter out of place” remains the quintessential Douglassian expression and is a keystone in both of her major efforts concerning dirt: Purity and Danger (1966) and the later essay “Pollution,” first published in the 1968 Encyclopaedia of the Social Sciences and subsequently included in the anthology Implicit Meanings (Douglas 1975). What follows is a summary of her theorizing on dirt in these texts.


Dirt, as we know from the famous phrase, is “matter out of place,” a definition that, Douglas states, implies two important conditions: “a set of ordered relations and a contravention of that order” (Douglas 1966: 44). To Douglas, “there is no such thing as absolute dirt” (idem: 2), and “no single item is dirty apart from [i.e. outside of] a particular system of classification in which it does not fit” (idem: vii). “Where there is dirt there is system” (idem: 44), because dirt is not an independent, objective attribute of something, but a “residual category [of things] rejected from our normal scheme of classifications” (idem: 45). It is a label for “all events which blur, smudge, contradict or otherwise confuse accepted classifications” (Douglas 1968: 50), and, importantly, it is a relative term – “what is clean in relation to one thing may be unclean in relation to another” (Douglas 1966: 10). Douglas illustrates these points with mundane examples: shoes, for instance, are not dirty in themselves, “but it is dirty to place them on the dining table” (idem: 44). Similarly, food is not necessarily dirty, “but it is dirty to leave cooking utensils in the bedroom” (idem: 37). Neither is dirty in an absolute sense, but is considered so due to its out-of-place-nessWhilst cooking utensils are dirty within the context of the bedroom, in the kitchen they are in the right place and hence – relatively speaking – clean. Dirtiness is less a property of things than it is a contextual label attributed to them.


Things may come to be “out of place” by being anomalous or ambiguous. Douglas defines an anomaly as any “element which does not fit a given set or series,” while ambiguity is a characteristic of something capable of two interpretations (idem: 47). In Douglas’ view, the categorization and organization (of objects, animals, senses, encounters, etc.) implicit in perception is, above all, an act of sense-making. Life, she suggests, is “inherently untidy” (idem: 5), and the separation and demarcation of experience into categories is an effort to “impose system” and make sense of the world (idem). Things that are anomalous or ambiguous are seen as dirty because they resist this kind of classification by not easily “fitting” into established categories. This directly threatens the perceptual (and inherently social) structure, and, as a consequence, anomalous and ambiguous things are often seen as disgusting, disruptive, and dangerous. However, these are not the only possible reactions; there is a “whole gradient on which laughter, revulsion and shock belong at different points and intensities” according to the type of transgression (idem: 47). What is consistent is that anomaly and ambiguity demand at least some kind of reaction because, as Douglas states, when we encounter them the underlying feeling is that “a system of values […] has been violated” (Douglas 1968: 50).


In order to counter the discomfort inherent in such transgressions, they must in the first place be limited, and, when they do occur, “fixed,” leaving dirt tidied up and dissonance reduced. Processes to achieve these ends are what Douglas refers to as our “pollution behavior,” and they are deliberate, creative acts. Eliminating dirt, she states, “is not a negative movement, but a positive effort to reorganize the environment” (Douglas 1966: 2), and the aim of pollution behavior is to ensure “that the order in external physical events conforms to the structure of ideas” (Douglas 1968: 53). One of the principal ways in which this is achieved is through the exaggeration of difference. Douglas states that it is only by exaggerating the difference between “within and without, above and below, male and female, with and against” that a “semblance of order is created” (1966: 4), as exaggeration sharpens the boundaries between categories which may otherwise be hazy or indistinct.


Once transgressions have occurred, they can be dealt with in a number of ways. Breaches of pollution rules may be “punished by political decree, sometimes by attack on the transgressor, and sometimes by grave or trivial sanctions” (Douglas 1968: 53), and additionally the simple act of labelling something “dirt” plays an important role, as the inherent negativity of the term serves to publicly condemn the contradiction or confusion of cherished classifications that has caused it. This has the effect of clearly outlining what is expected and acceptable and what is not. As Douglas writes: “when something is classified firmly as anomalous [or ambiguous], the outline of the set of which it is not a member is clarified” (Douglas 1966: 47). In other words, labelling something “out of place” (and therefore dirty) simultaneously establishes what would be “in place” (and therefore clean). In Douglas’ example of shoes on the dining table, for instance, calling the situation dirty reinforces the idea that, usually, shoes are not placed on the dining table, and it is hoped that the act of labelling such behavior “dirty” will cause the offender to recognize the out-of-place-ness of their action and “fix” the transgression by revising the placement of the shoes.

Of course, what is “out of place” to one person may not necessarily be so to another. Dirt exists only “in the eye of the beholder” (Douglas 1996: 2), and what is classified as dirt varies between groups and individuals. Although dirt can be consistently defined as “that which must not be included if a pattern is to be maintained” (Douglas 1968: 50), what constitutes a “pattern” or what is considered a desirable pattern has no such consistency. Whereas the “sorting” of perception (and experience) into categories is a human universal, their boundaries are entirely a matter of culture. Indeed, pollution behaviors form a central part of what we mean when we speak of “culture,” as dirt, by definition, invokes the wider structure of which it is not a part. Additionally, due to their important role in reinforcing and maintaining the social order (i.e. outlining what is and isn’t acceptable behavior), pollution rules take on a deeply symbolic role, and dirt, according to Douglas, carries a “symbolic load” (Douglas 1996: 4). The labels “clean” and “dirty” can be mapped on to more overtly moral ones such as “pure/impure” and “sacred/profane,” and pollution beliefs are used “in a dialogue of claims and counter-claims to status” (idem: 3). To be “clean” is to be good, to agree to cherished classifications, and to uphold the social order and accepted ways of being. By contrast, to be “dirty” is to be bad, to disregard convention, to confuse or ignore classifications and have different and unacceptable ways of being. Dirt, far more than just “matter out of place,” is indicative of an entire moral system.