The Oxford English dictionary defines purity as the "quality or condition of being pure: the state of being unmixed... freedom from manner that contaminates, defiles, corrupts, or debases; physical cleanliness." Such a characterization includes two key components; the idea of purity which generically and categorically opposes itself to "mixing", and the idea of purity as a desirable and idealized attribute. We can thus discuss the concept of purity both as a value judgement and as the description of an object's (or idea's) natural state.
In this definition, purity is not simply an objectively "unmixed" state, for a specified and definite value judgement is implied. Purity carries with it clear notions of benefit, good, and desirable, whereas its contrasting state (the state of being mixed) is characterized as an abyss of baseness. The definition elaborates on this idea of general cleanliness, describing possible areas in which purity (and its opposite, impurity) might appear; a given thing can be described as pure on a sexual, physical or moral level. Purity as a natural state is inherently part of this definition as well; for mixing, tampering, or corrupting are all actions which require outside agency. If these actions are the cause of impurity, then purity is the condition of the object/idea prior to the interference of such external forces, its condition if left in its natural, solitary, unagitated state. Such an attribution of purity to the hand of nature serves to underline and emphasize the societal judgments which are equally implied by the use of the word. Nature lends its authority to the societally supported value structure, which labels purity as "good" and impurity, or mixtures, as "bad".
Ideas of purity in the media seem to take two general forms. Purity is to be found either in the complete denial of the medium or else in its opposite, the complete embrace of that medium as form and content combined. The use and emphasis of media forms can, following the doctrines elaborated by, for example, Greenberg and the abstractionists, lead to purity within the chosen medium. However, according to Plato and Kant, any use of media at all serves to taint and corrupt the purity of intellectual ideas. Purity naturally seems to tend to extremes, as could be expected from an idea containing such an inherent binary opposition (mixed/unmixed, clean/soiled, etc.) Purity is an absolute; one cannot be mostly pure, or almost unmixed. Purity is an all-or-nothing proposition.
Perhaps the classic example of purity as an ideal and a concept occurs in the writings of Plato. His world of forms is a powerful evocation of ideal of purity. In the Phaedrus, Socrates describes an upper realm of truth and reason, where the forms exist, and can be perceived truly. However, the complete vision of truth (and Beauty, and Justice, etc.) is not available to all souls, but only to the gods. Humans are able to catch glimpses of these truths through art or discussion, but such media can only be shadow copies of the pure and true Forms. The Forms represent an unmixed, uncorrupted truth about the world, which is increasingly distorted/corrupted/made impure through the media that humans must use in order to explain and represent those truths. In his philosophy the only possibility for true purity exists in intellectual discourse, and the realm of ideas. The interpretation of pure ideas, pure Forms into any sort of physical reality, be it painting or sculpture, or even simply writing, is inherently problematic, and will inevitably defile the purity of the ideas in question. Plato opposes media on principle, for their inability to ever truly reproduce the truth and intensity of pure ideas. Media come closest to purity at their most transparent, which is why he prefers speech to writing--it is more immediate, and communication between two people is less subject to the problems and confusion of mediation that occur when ideas are transcribed into written text. Nonetheless, despite his objections, Plato is an author and a user of media. His very dismissal of media on theoretical grounds serves as practical proof of their necessity and importance, for he must use them to communicate his disdain.
Writing much later, Immanuel Kant also shares this concept of purity, which resides in an intellectual (not physical) realm. Intellectual purity is characterized by its intuitive qualities. Geometry can be pure because we perceive shapes and their relations immediately, without needing any messy proofs or experiments. Our understanding is unmediated by the physical (impure) world. Pure perception, pure ideas, pure understanding are pure because they are arrived at spontaneous, not through empirical processes. The idea of purity reflects a denial, as much as possible, of media forms, for pure perception occurs intuitively, and immediately, without the interference or need for media.
In the arts, however, fields invested in media, the concept of purity has played a different role. Unwilling or unable to dismiss all forms of mediation as inherently impure, art criticism has a history of attempting to define purity within a given medium. The mixing which is to be avoided is not the mixing of intellect and corporeality but the mixing of different types of media into conglomerates that ignore their individual "pure" identities. In Lessing's Laocoon, the author attempts to demonstrate clear, qualitative differences and boundaries between painting and poetry, limits which, if strictly adhered to, would produce better (more pure) forms of both media types. Lessing, and art theorists after him, do not attempt to render the medium transparent or nonexistent, like Plato might have, but instead search for the defining characteristics of that medium.
Clement Greenberg and the abstract painters whom he championed also focused their efforts on achieving purity within the context of art media. They argued that, in fact, it is essentially concern with and a focus on the physical medium itself that produces pure art. Abstraction became a way that painters could distance themselves from subject matter, which emphasized the transparency of the visual medium and made it dependent and subservient to literature. A focus on content, according to Greenberg meant that the unique physical properties of painting were ignored in order to tell a story or represent scenes, goals which should belong exclusively to literature. Realist painting styles aimed for illusion--for a representation so convincing that a viewer would not realize that his sight experience was mediated. Painters rejected naturalism to work with shape, color and space, embracing the very physicality of the flat surface and painting techniques that emphasized form over content. Greenberg wrote that in order for a painting to achieve separation from literature and purity of its own nature, it required an, "escape from ideas." ( Towards A Newer Laocoon ) Subject matter was made irrelevant and the focus turned to the medium itself. Plato's pure Forms, concrete ideas of Truth, Beauty, Love, etc. are replaced by pure forms which represent nothing, whose physical presence is both the reason and meaning for their existence. The planar surface of the canvas, which representational painters had previously worked at virtually erasing through the use of perspective, became a dominant feature in much abstract art. The flatness of these works reflects Greenberg's ideals of purity as embodied by the medium.
Michael Fried also addressed questions of media purity. He objected to the minimalist school of art, whose works attempted to achieve the status of non-art, by exaggerating and embracing the materiality of the work, to the exclusion of anything else. Fried argued that instead of achieving purity through their efforts, these literalists created inherently mixed media theatrical installations where the presence of the object/art and its interaction with the spectators is as important (if not more important) than the physical object itself. Thus the very focus on materiality in this extreme theory leads not to purity but to the antithesis of art and artistic purity, which is theater. Fried writes that, "what lies between the arts is theater." (Art and Objecthood) The literalist installations fail to achieve the purity of, for example, abstract painters or the sculptor Anthony Caro, by their very lack of artistic differentiation between the art and the object. (see objecthood)
Thus pure painting becomes painting which is concerned with the act of painting and the qualities of a painting (color, texture, etc.) The avant-garde's exploration of these ideas opens up the possibility for multiple types of purity--pure poetry, for example, is pure for different reasons than an abstract painting is considered pure. "Pure poetry" generally refers to the ideals described by Poe, Baudelaire, Mallarmé, and Valéry. Their theories call for an emphasis on lyricism and musicality in order to produce emotional and psychological effects; ideals which are very different from the physical, plastic ideals embraced by abstract painters. Thus, in the differences between media, we can see the possibility for varying approaches to and examples of purity. Plato's conception of a single embodiment of purity--purity as an intellectual and spiritual construct--is dismissed in the interest of different media forms.
However, one inherent problem with purity is consistent in both Plato and later abstract artists. This is the question of value. For both theories of purity (intra-media purity and anti-media purity) operate on the assumption of positive values inherently linked with pure forms. This insistence on purity's value instantaneously denies any possibility for powerful art in a deliberately mixed medium. If mixing is always equated with defiling, then what purpose is to be served by intentional attempts to cross the boundaries so rigidly established by theorists? In thinking about this question, it is important to note the overwhelmingly sexual context that discussions of purity have tended to take in our society.
Even more than the arts, questions of purity are linked with sexuality, a realm where positives and negatives are perhaps not quite as concrete as the clean/dirty, good/bad opposition seen up to this point. While historically, purity has occupied a sanctified position (Puritan tenets of chastity come to mind) today's attitudes are decidedly more ambivalent. Modern women's magazines (which may be kitsch, but nonetheless reflect some general societal truth) carry articles about how to be a sex kitten, and popular movies like American Pie glorify purity's defeat. Purity does indeed carry positive connotations in the sexual sphere, of virginity, incident, etc. However, implicit in this understanding are the equivalent ideas of ignorance and lost opportunities. Sexual impurity can be read either as corrupt (following the value standards of the aestheticians) or it can represent increased intensity, knowledge and experience. If we view mixed media projects through this more ambivalent and less clearly judgmental lens (of sexuality), the potential for impure (but "good") art appears. Further, this elaborated reading of purity itself can serve to cast doubts on the very tenets of the standards advocated in the past.