Beyond the Mirror World:
Privacy and the Representational Practices of Computing

Philip E. Agre
Department of Information Studies
University of California, Los Angeles
Los Angeles, California 90095-1520

This is a chapter in Philip E. Agre and Marc Rotenberg, eds, Technology and Privacy: The New Landscape, MIT Press, 1997.

Please do note quote from this version, which changed slightly before publication. This version also omits several figures that can be found in the print version.

9000 words.


In January 1996, the California Air Resources Board (ARB) issued a Request for Proposals (RFP 95-7) entitled Incorporation of Radio Transponders into Vehicular On-Board Diagnostic Systems. The ARB observed that, starting in 1996, new cars and light trucks in California will be equipped with an on-board diagnostic (OBD) system that illuminates a dashboard indicator when it detects a malfunction in the vehicle's emissions system. It also observed that drivers may not actually get their malfunctioning cars fixed until their next scheduled inspection check. With an eye to enforcing compliance with emissions laws, therefore, the ARB proposed to build a fleet of ten test cars, each equipped with a transponder that is capable of transmitting the OBD error codes to roadside (or possibly satellite-based) receivers. Specifically, in response to a query from the receiver, the RFP specifies that the transmitter is able to supply the following information:

the full 17-digit vehicle identification number (VIN) of the vehicle
any fault codes reported by the OBD system
the location of the vehicle at the time of query
a status code
The receiver should be able to store the date and time of all queries to passing cars, along with the information that the cars return, including "vehicle location (to the zip code level, and city)". Although this RFP only envisions the construction of test vehicles, the successful bidder is asked to analyze the system's cost effectiveness "assuming that 1,000,000 vehicles equipped with the [transponder-equipped diagnostic system] are added to the fleet beginning in the year 2000".

The ARB system is presumably intended to be used only for its stated purpose, ensuring compliance with emissions regulations. The fact is, though, that the system as specified could easily be used to track the location of every car that is equipped with it, regardless of whether it has any fault codes to report. The potential for abuse ought to figure significantly in any weighing of risks and benefits from the system, especially given that the newer cars on which the system would first be installed are the least likely to experience emissions system malfunctions. What is so striking about the RFP, though, is not that it is unusual. To the contrary, the RFP takes for granted a whole vocabulary of technical methods that has become familiar and widespread. The winning bidder, for example, is instructed to "investigate the possibility of coordinating this effort with other agencies or entities", so as to "suggest the most effective and efficient infrastructure for statewide electronic fleet monitoring". These other agencies include the California Department of Transportation, which has been working on transponder-based toll collection projects for several years, using a transponder architecture that is expressly designed to be extensible to other applications.

The ARB is not unaware of the privacy concerns that their plans may raise. These concerns are described at length in a report on legal issues (Di Genova and Macomber 1994) by the previous contractor on the emissions monitoring project. They have also been reported in the press (Rogers 1996; Halpert 1995). Although the project may conceivably be derailed by protests from affected industries, on a technical level the system retains a sense of inevitability; it seems clearly the logical culmination of a path of technical development. Although wireless capture of onboard fault codes has been rendered practical only recently through decreasing costs of microprocessor power and digital wireless communications, little about the RFP is technically new or difficult; any competent computer systems designer can imagine how it might be embodied in a working system. Such a system, moreover, would be similar in its workings to hundreds of other computer-based technologies for tracking human activities that have arisen in recent years, or that are currently being developed. Together these technologies constitute, in effect, an emerging infrastructure -- decentralized to be sure but pervasive nonetheless -- for the systematic surveillance of numerous spheres of human life.

Ever since the rise of organizational computing in the 1950s, social imagination has always associated computing with surveillance. The reasons for this association are clear enough: computer systems analysis and design promptly took up and generalized the methods of rational administration that organizations had developed throughout the modern era (Clement 1988). The technical concept of "algorithm" was assimilated to the bureaucratic concept of "procedure", and the technical concept of "data" was assimilated to the bureaucratic concept of "files". So long as computers have been understood in this manner, as inherently suited to social relationships of rationalized control, debate about privacy has been structured as a series of tradeoffs, and by the assertion of abstract rights (such as dignity, autonomy, association, or self-determination) against specific encroachments (each accompanied by a compelling justification). Lyon (1994), for example, accurately notes that the same technologies that have raised concerns about a "surveillance society" have historically made possible many benefits that most citizens would prefer not to surrender. Society, prodded in part by the resistance and agitation of concerned groups, may respond to such dilemmas by shaping data-protection regulation, but the resulting regulatory process must always contend with the putative benefits of particular surveillance technologies.

The technical methods of computing have always defined the landscape across which these controversies are conducted (Pool 1983, p. 251). Until very recently, though, these technical methods have not themselves become matters of dispute. Computers as cultural objects have, in effect, been essentialized -- treated as a stable category with fixed relationships to larger social practices. This ahistorical understanding of computers has eroded somewhat in recent years as citizens have experienced the endless turmoil of the personal computer industry first-hand. The emergence of computer networking technologies such as the Internet, moreover, has popularized an alternative, liberatory construction of computers that focuses on their communications function (Feenberg 1995). Significant changes in computer architecture do appear occasionally, such as the emergence of RISC architectures in the early 1980s (Radin 1983). Nonetheless, certain fundamental aspects of computer architecture have remained stable. The vast majority of computer processors are still serial, and virtually all of them employ the register-transfer model that first arose in the 1940s. Calculations are still overwhelmingly digital, and computer memory still consists of a hierarchy of media, each indexed by a linear sequence of addresses. On the whole, computing has progressed by augmenting and accelerating basic architectural choices, not by replacing them. Although technical research projects have proceeded in many directions, the innovations that have become widespread in actual practice generally been built on top of existing methods, or they provide generalizations or rational reconstructions of existing practice.

The architecture of a computer does not completely determine its use in institutional contexts. Even so, computer systems design and practices of rationalization have evolved together in a slow, continuous motion for fifty years. The purpose of this chapter is to explore this evolution. Although some valuable histories of system design practice as a whole have been produced (Edwards 1996; Friedman 1989), my particular goal is to gather some fragments toward a history of data. Computers raise privacy issues when organizations use them to represent human beings and their lives, and by analyzing the history of these representational practices I hope to make the architecture and social practices around computing seem less immutable. This history, as subsequent sections will make clear, is not a matter of linear progress. The concept of data changes over time, impelled both by the metaphors of technical language and by technical practitioners' experiences in trying to get their systems to work. Toward the end of the story, two things happen at once: a mainstream, data-centered model of computing emerges alongside a model based on public-key cryptography. I will argue that the various models of data, despite their seeming differences, are coherently related to one another and to the institutions of computing.

Although I will sketch these models of data, my main purpose is not technical exposition. Instead, I wish to explore the "practical logic" of computing work (Agre, forthcoming). What happens when a technical community with a definite worldview, perhaps influenced by certain metaphors, puts that worldview into practice? Any given metaphor will necessarily consign certain aspects of reality to the practitioners' peripheral vision. A metaphor may even misrepresent the very methods that supposedly embody it. To the extent that practitioners apply their methods in concrete situations, though, the marginalized features of reality will reassert themselves -- most likely in the form of recurring patterns of difficulty whose nature may not be clear at first. The progress of technical work is, in this sense, largely reactive: the technical community applies certain metaphors in organizing its work, a certain pattern of difficulty emerges, and the existing methods are modified or extended according to some understanding of the difficulties. Only rarely will an entirely new metaphor arise, and then the old and new metaphors are likely to coexist, whether as competitors or complements. New methods arise when a new metaphor makes sense of large parts of practitioners' experiences, but they are only adopted once they can be fitted into the sprawling network of other methods by which the technical community as a whole designs and builds complex systems. In this way, computer work develops through the influence of its language, the mutual constraints of its methods, and the recalcitrance of the world that lies beyond both. Reconstructed historically, this development makes a certain kind of sense, and this sense is the practical logic of the work.

Representing Activity

The first methods for representing human activities on computers were derived from the work-rationalization methods that industrial engineers had been developing since the 1910s. Thus the phrase "information processing": the idea was that computers automate a kind of factory work whose raw material happens to be information rather than anything physical or tangible.

Industrial engineers, starting with Taylor (1923) and Gilbreth (1921), developed two broad categories of representations: process charts for representing the flow of materials through a manufacturing process, and time and motion study diagrams of particular jobs. Much has been written about the sociology of early work rationalization (Braverman 1974; Guillen 1994; Montgomery 1987; Nelson 1980; Thompson 1989), but I am specifically concerned with work rationalization as a representational practice. How, and in what sense, do computers come to embody representations of human activities?

Figure 1 presents an example of a process chart that follows the progress of various parts, and the various operations performed on them, in the assembly of a tin for storing tea. Note, first of all, that the representational scheme consists of a small vocabulary of discrete elements. These elements can be used both to represent an existing form of activity and to prescribe a new one. In each case, the scheme presupposes that activities can be broken down into discrete units. These units need not be sequential (i.e., they might overlap), but they identify discrete categories of action into which particular empirical streams of action must be parsed.

Figure 2 presents Gilbreth's units for motion study, the "therbligs"; this particular diagram of the therbligs is from Shaw 1952. Once again, the idea is that work activities can be decomposed into a fixed set of categories (search, find, select, etc.). Figure 3 provides an example of the therblig notation scheme in action; in this case, each action is decomposed according to the respective roles of the worker's arms, fingers, and palms, both left and right. The therblig system includes units for representing rest and delay, and it includes a unit to represent moments when the worker must stop to construct a plan. This latter unit is distinctive. In Derrida's (1976 [1967]) terms, the "plan" therblig is the supplement of the system: an extra term that closes up a gap in the system while simultaneously embracing it as a whole. The whole idea of motion study, after all, is to minimize or eliminate this extra term by displacing the planning effort into the work of engineers. By making this supplementary term an explicit part of his representational scheme, Gilbreth acknowledges, if only directly, that reality always surpasses any particular representation of it. Subsequent schemes in the same tradition generally did not make room for explicit planning, but they did build upon a vast body of practical experience in getting such schemes to work.

Couger's (1973) survey of the emergence of systems analysis methods in computing makes explicit the connection between Gilbreth's use of process charts and later computing practice. The initial concern was the flow of forms in an organization. The rationalized organizational use of paperwork was highly developed before the invention of the computer (Yates 1989), and computing practice drew on an established tradition of automating paper-based work. Figure 4, for example, a tabulating machine process chart from the 1940s, represents the flow of Hollerith cards through various machines. Each card corresponded to a particular record, in this case records specifying orders and production levels for various models of a company's products. As this diagram makes clear, techniques used to map the flow of parts in manufacturing were carried over to the flow of documents in the course of "manufacturing" other documents. The focus was on the documents as physical artifacts, to be processed like any others, and not on the meaning of the various representational elements in the documents. The representational nature of the documents, in other words, was secondary. The systems analyst's job was to represent the forms, not the things that the forms represented. The transition from paper forms to Hollerith cards to database entries was gradual and uneven, and the concept of information served to abstract the common functionality of these media without drawing any particular attention to the representational nature of media themselves, or to the facts about the world that these media conveyed. This accounts for a curious feature of the information processing metaphor: information is treated as a tangible, measurable substance, but only in a minimal sense does the information seem to be about anything (Agre 1995a). Couger (1973, p. 196) concludes his survey by pronouncing it "amazing" that systems analysts had made little use of computers to construct the representations that they employed in their work, even though their work consisted in the design of computerized representations. But in retrospect the discrepancy makes sense: the early systems analysts did not recognize much commonality between the representations (process charts) that they manipulated in their work and the representations (office documents) that were manipulated by the people they studied.

The Mirror World

The information processing metaphor proved misleading in important ways. Having been motivated by the automation of existing work methods based on paper forms, it was not particularly helpful to database designers, whose task was to devise record-structures for new categories of digital information. The original databases were inevitably modeled on the tabular information that had long been stored on paper forms, with rows that corresponded to particular things in the world and columns that corresponded to particular attributes of those things.

This view of data was formalized by Chen (1976) in the entity-relationship model of data. Although many databases had been designed in the two decades before Chen's highly influential paper, the entity-relationship model brought database design into focus as a body of practitioner experience. Perhaps its greatest conceptual innovation was a clear distinction between data records and the entities that they represent. Though seemingly abstract, the point was not philosophical but organizational; by starting the design process with an enumeration of entities, the database designer is supposed to ensure that the resulting design reflects actual business needs. Database designers, after all, were generally trained as general-purpose system analysts rather than in the particular industry whose substance the data was to represent, and their attention was naturally focused more on databases as such than on the categories that were implicated in particular applications domains. Nor was the point at all obvious; even a contemporary manual of data modeling (Reingruber and Gregory 1994), in trying to define the concept of an entity, repeatedly blurs the distinction between records and things. Having surveyed various definitions of "entity" in the literature, Reingruber and Gregory (p. 64) extract the following themes:

An entity is a `thing' or `concept' or `object'. . . . Or it may represent the fact that we need to capture information specific to only a subset of the instances of an entity. . . .

An entity is not a single "thing", but rather a representation of like or similar things that share characteristics or properties. For example, King Lear and Hamlet are both plays, and have properties such as name, author, cast of characters, and lines of verse. The entity describing these might be PLAY, with King Lear and Hamlet as examples or instances or occurrences of PLAY. . . .

Entities involve information. The "things" that entities represent are things about which the enterprise wants or needs to retain. . . .

These sentences shift repeatedly between treating entities as things in the world and treating entities as representations of things in the world. Their choice of example facilitates the confusion, given that the word "play" refers to both the text and the performance, the representation and the thing represented. Reflecting on the above points, they "refine our view of entities" as follows:
Entities are collections of attributes that satisfy a particular set of rules established for relational modeling. (ibid., p. 64)
This definition is perfectly ambiguous. Real things can, with some effort, be viewed figuratively as collections of attributes, but entity-relationship data records are precisely collections of data elements called attributes. These authors may have been misled by the practice, common but usually well defined in the literature, of using the word "entity" to refer both to categories of things (cars, people, companies) and to instances of those categories (my old 240Z, Jacques Martin, IBM). Be this as it may, the conflation of representation and reality is a common and significant feature of the whole computer science literature. (In artificial intelligence, for example, formally specified activities such a chess and logical theorem-proving serve the purpose that plays serve for Reingruber and Gregory.)

The entity-relationship approach employed a graphical notation, a recent and relatively streamlined version of which is found in figure 5. Each box in this diagram stands for an entity and each link stands for a relationship, with symbols on the links that indicate whether the relationship is one-to-one (for example, cars and engines) or one-to-many (for example, cars and wheels), and whether the relationship exists necessarily (every car has at least one seat) or optionally (a car may have a roof but need not). This notation scheme can express distinctions of a certain degree of ontological delicacy, but only up to a point. During the same period, by contrast, AI research in knowledge representation developed a complex multilevel analysis of ontological and epistemological categories for the purpose of representing structural relationships that are much more complex than have usually arisen in business data (Brachman 1979; Borgida 1991). Within database research, similar but less ambitious work on semantic and conceptual data modeling has had little influence on mainstream practice. Instead, the mainstream focus has been on the business significance of large databases of relatively simple records that can be searched quickly.

During the 1980s, then, data became increasingly central to the practice of computing. Even though the design of a database accounts for a minor portion of the overall cost of designing a system, the structure of data has profound consequences for the design of algorithms. Once created, data can be used for a variety of purposes, including purposes that were not envisioned when the database was originally designed. Database designers therefore increasingly viewed their work as independent of program design, and they evolved canons of good practice that responded to cases where database designs failed to generalize to new applications. Amidst these imperatives, there arose a new model of computing. Whereas information processing was primarily concerned with the structure of processing, the newer model was primarily concerned with the structure of data. And the purpose of data was to reflect the repertoire of entities in which the business dealt.

The apotheosis of the emerging data-centered view of computing is a popular book entitled Mirror Worlds, written by the prominent computer scientist David Gelernter (1991). Mirror Worlds repays close reading. As the title makes clear, the book's central metaphor is the computer as a mirror of the world; Gelernter suggests that the progress of computing will inevitably produce a single vast distributed computer system that contains a complete mirror image of the whole of reality. Although the computer as mirror is at best a tacit theme in the database literature, Gelernter makes it thoroughly explicit and offers it as a way of extrapolating current directions in technical development:

You set up a software mirror wherever you like, then allow some complex real-world system to unfold before it. The software faithfully reflects whatever is going on out front. (p. 6)
The Mirror World, Gelernter suggests, will permit individuals to investigate reality without leaving home, simply by "traveling" in the digital mirror:
Capturing the structure and present status of an entire company, university, hospital, city or whatever in a single (obviously elliptical, high-level) sketch is a hard but solvable research problem. The picture changes subtly as you watch, mirroring changes in the world outside. But for most purposes, you don't merely sit and stare. You zoom in and poke around, like an explorer in a miniature sub. (p. 15)
Video cameras figure prominently in his vision, as befits the optical metaphor of the mirror:
Eavesdrop on decision making in progress. Among other things, you will discover video feeds down here. When you dive into City Hall, one part of the display on your screen might be a (little) TV picture. You can mouse over there and enlarge the thing, if you want to hear the mayor's press conference or the planning board meeting. (p. 17)
Gelernter is well aware of the privacy concerns that computers have raised, and much of his book is concerned with the nature of public space in the era of the Mirror World:
The Mirror World isn't snoopware. Its goal is merely to convert the theoretically public into the actually public. What was always available in principle becomes available in fact. Organized, archived, spiffily presented, up to the minute and integrated into a whole. (p. 19)
As the last phrase suggests, one purpose of the Mirror World is to repair social fragmentation by making it possible to grasp the world as a totality through its computer representation. Gelernter refers to this form of understanding as "topsight":
If insight is the illumination to be achieved by penetrating inner depths, topsight is what comes from a far-overhead vantage point, from a bird's eye view that reveals the whole -- the big picture; how the parts fit together. (p. 52)

It used to be generally conceded that whole-sightedness -- a due respect for what Madison calls "the permanent and aggregate interests of the community" -- was a good thing. Today, all sorts of angry factions are proudly dedicated to the methodical tearing-to-shreds of public life. Rapacious PAC lobbyists in Washington and multiculturalists at Stanford are quite agreed that a little E pluribus unum goes a long way. (p. 31)

Gelernter views Mirror Worlds (which are sometimes singular, sometimes plural) as extensions of public spaces that can facilitate democratic decision making:
. . . Mirror Worlds function in part as fire walls opposing the onslaught of chaos. But they aren't mere fire breaks. They are beer halls and grand piazzas, natural gathering places. (p. 6)

Every Mirror World neighborhood is equipped with a public message board. Candidates can post statements. Toward election time, we can set up a special political playground, where they can hold forth at greater length. (p. 23)

In response to fears that computers are necessarily instruments of social control through surveillance, Gelernter argues that the Mirror World will make it possible for ordinary citizens to turn that same power of surveillance back against the state:
Mirror World is some huge institution's moving, true-to-life mirror image trapped inside a computer -- where you can see and grasp it whole. The thick, dense, busy sub-world that encompasses you is also, now, an object in your hands. A brand new equilibrium is born. (p. 3)

[Mirror Worlds] scotch that great primal modern fear, to be entangled by the sucker-arms of the modern institutional state, and all those private mini-states within which . . . we hang embedded. They offer penetrating vision; they repair the shattered whole. (p. 184)

In this latter passage, Gelernter suggests that Mirror Worlds will offer defenses against both the state and the "private mini-states", but he does not develop this metaphor of private organizations as states or address the politics of making private organizational information public.

In response to critiques of representation that associate it with emotional drives for domination and control (e.g., Walkerdine 1988), Gelernter embraces those drives and promises to democratize them:

Don't mistake this topsight search for a mere intellectual drive. It's an emotional quest too. . . . our grandest accomplishments reflect the innate urge to dominate. . . . The pursuit of topsight is intellectually compelling because it is emotionally compelling. . . . what lends [Mirror Worlds] a uniquely potent potential is the submerged iceberg mass of their emotional appeal. . . . topsight to the millions. . . . (p. 184)
Gelernter is aware that security concerns will arise:
Many Mirror Worlds will contain a good deal of confidential information. Professional thieves will certainly be attracted. (p. 197)
Moreover, despite his major emphasis on those parts of the world that are normatively open to public view, such as public spaces and the state, Gelernter also offers a model of selective access to the sensitive information that these vast databases will surely contain:
Granted, lots of new information-gathering devices have been installed. But the information they are gathering and feeding into the Mirror World is strictly public information -- or information to which this particular Mirror World's clientele is entitled. And the Mirror World will discriminate judiciously among visitors. The public at large, for example, is entitled to enter the City Hospital Mirror World, and to learn a good deal about what's going on. Furthermore, anyone is entitled to see his own medical records. But very few people have access to anyone else's, although they are all stored down here. Access to private information is closely controlled. (p. 19)
To implement this version of access control, Gelernter complicates his metaphor of travel in a Mirror World landscape:
The Chief Cameraman is a crucial figure in the Mirror World landscape. . . . he knows who you are. He knows exactly which televiewers belong to you; which are public; which are private, but you're allowed to see; and which you are not allowed to have anything to do with. (p. 196)
Gelernter, clearly, is a technological utopian who seeks to refute the technological pessimism of the social theorists. He regards the Mirror World and its political benefits as inevitable -- immanent in the technology as it is already developing. Despite his contempt for interest-group activism and the entangling tendencies of the modern state, he is not a libertarian. To the contrary, he seeks a democracy of liberal individuals, and he thinks of the Mirror World as a collective undertaking through which the conditions of liberal democracy might be established:
The real software revolution . . . will center . . . on software that steps over the crucial boundary between private and public. It will have to do with "public software works" with civil software-engineering, with Mirror Worlds. The software revolution hasn't begun yet; but it will soon. (pp. 7-8)
Despite his focus on the public sphere, to be sure, the traditional rhetoric of organizational control (Beniger 1986) resurfaces whenever Gelernter's standpoint shifts from that of the ordinary citizen to that of the organizational leader:
A parable: consider the modern, state-of-the-art fighter aircraft. It's so fantastically advanced that you can't fly it. It is aerodynamically unstable. . . . Modern organizations are in many cases close to the same level of attainment -- except that, when they're out of control, they don't crash in flames; they shamble on blindly forever. (p. 19)

It isn't easy for a hospital administration with the best of intentions to make sure that bad or inappropriate or newly outmoded or wrongly sequenced or mutually inconsistent or maximally expensive or unnecessarily dangerous procedures are never scheduled. A battery of software agents planted in a Mirror World can watch for bad practices full-time. (p. 20)

This is a point of instability in Gelernter's argument. At some moments he presents the Mirror World as a mirror of the public world, but then at other moments he presents it as a mirror of the entire world. The Chief Cameraman appears on moments when it is necessary to negotiate this difference.

Gelernter's conception of data differs greatly from the information processing metaphor. The metaphor of information processing has not vanished, but it has gone backstage. The computational mechanisms concerned with constructing, maintaining, and using the Mirror World are still called processes, and Gelernter uses a hydraulic metaphor to describe them:

Oceans of information pour endlessly into the model (through a vast maze of software pipes and hoses): so much information that the model can mimic the reality's every move, moment-by-moment. (p. 3)

A Mirror World is an ocean of information, fed by many data streams. . . . Data values are drawn in at the bottom and passed upward through a series of data-refineries, which attempt to convert them into increasingly general and comprehensive chunks of information. As low-level data flows in at the bottom, the big picture comes into focus on top. (p. 27)

Despite the change of metaphor, then, the technical methods that Gelernter describes are not radically different from those of classical systems design. The mirror metaphor and the information processing metaphor are more like two sides of the same coin, logically independent perhaps but each connected to the other within the discourse of computing as it has evolved historically.

Representation and Professional Distance

These metaphors are constituents of a discourse; what, though, about the practices? Gelernter intends to project the future development of computing technology, and in one sense he is correct: the mirror metaphor provides one way of expressing a central theme in recent technologists' visions of computing. Research on virtual reality, for example, is predicated on the idea that computerized gear attached to a user's body can create immersive "worlds" that deserve to be called a substitute for reality (Benedikt 1991). Likewise, a massive community within the computer research world is concerned with simulating reality for a wide variety of purposes. The US military has heavily funded such research in support of its ambitious attempt to blur the distinction between real and simulated battlefields. One battle during the Persian Gulf War, for example, was thoroughly instrumented and recorded so that later training exercises could recreate it in fine detail and explore different directions that it might have taken (Sterling 1993). This project is continuous with the larger phenomenon that Edwards (1996) calls "cyborg discourse", which treats human beings, social institutions, and the natural world as components of one overarching "system". Even when extravagant ideologies of this kind are missing, the mirror metaphor aptly expresses the most basic procedure of traditional computer systems design: prepare a roster of the entities that are present in some part of the world, determine which relationships among those entities are significant for the tasks at hand, and create data records whose structures and interconnections map those entities and relationships one-for-one. Simply put, the computer profession is trying to reproduce the whole world in the workings of machinery.

Gelernter's vision, then, is congruent with much of the overtly articulated motivation for pervasive computerization in contemporary industrial society. His optimism about this vision, though, is hard to evaluate. One approach would be to accept the metaphor and dispute his sense of proportion: Mirror Worlds, while increasing the capacity of citizens to conduct computer-mediated surveillance against the powerful, might be held to increase the already vastly greater capacity of the powerful to conduct surveillance of their own. But this argument, which perhaps accurate, is not particularly compelling.

A more sophisticated analysis must begin with the mirror metaphor itself. In fact this metaphor permits Gelernter, presumably without intending it, to gloss over numerous features of the actual practice of computing, namely the diverse forms of mediation between representations and reality (Agre 1995b; Bowers 1992; Star 1989). Let us consider a few of these.

* Ontology. A computer can only capture and calculate with what it can represent. A Mirror World can feed video streams into citizens' living rooms and store them in databases, but it will not be able to interpret them in any significant way. The Mirror World's ability to summarize, abstract, or evaluate the world will depend on the ontology embodied in its representations.

* Standards. To have any hope of representing the world in a compact and useful way, a Mirror World will require that the same ontology, or a manageably small set of ontologies, be used to represent human affairs the world over. But this kind of ontological uniformity can only be achieved through the uniform imposition of standardized categorizations and measurement schemes (Bud-Frierman 1994).

* Instrumentation. A mirror can be installed next to an activity without having much effect on it. But if an activity is to be reflected in a computer database, its participants must somehow be provided with equipment that can capture the necessary data. This instrumentation will normally require that the activity be reorganized in some way, for example by requiring employees to enter certain data after each job. The introduction of new formal methods can lead to subtle and pervasive reorganizations in the equilibrium of work in a given site (Berg 1997).

* Authentication. A Mirror World which claims to report the activities of particular people and things must presuppose some material process to verify their identity. The mirror metaphor postpones this requirement, displacing the need for identification to the end user of the system who observes the activities at a digitally mediated distance.

* Interpretation. Gelernter predicts that Mirror Worlds will eliminate the need for political interest groups by providing everyone with equal access to an overall view of society. This assumes that the necessary syntheses of raw data can be performed automatically. In reality, one major function of an interest group is its interpretation and synthesis of information. The work of a legislative analyst, for example, is nowhere near being automated, although perhaps it can be displaced geographically from the legislature as drafts of legislation become available on line.

* Selection. If a Mirror World is easy to set up then presumably anybody can set one up anywhere. But as the complexities of mirroring become more evident, the question arises of which data are created in the first place, and which are stored. Gelernter (1991, p. 27) acknowledges that data streams generated by environmental sensors can easily create more data than could possibly be stored. But he assumes that choices about filtering and storage of the data can be made automatically while preserving the utility of the system for users.

* Bias. Citizens using a Mirror World to gain an overview of the real world will depend on a great deal of software. But software can embody biases that are not obvious to its users, or even to its authors (Bowers 1988; Friedman and Nissenbaum 1994). Seemingly objective calculations are routinely deployed for strategic purposes (March and Olsen 1989). The mirror metaphor promises an undistorted image of the world, or at worst an anamorphic image if the mirror is warped, but other types of bias are harder to conceptualize within the framework that the metaphor provides.

* Performance. Once Mirror World surveillance becomes pervasive, people will design their activities with an eye to their consequences of surveillance (Dourish 1993; Suchman 1992). The activities will become, in effect, staged performances that project, to the greatest possible extent, the participants' preferred construction of reality.

The mirror metaphor, then, minimizes our sense of representations as material things. Computer representations differ from the reality of human activities in many ways, and computers' ability to create and maintain representations of human activities presupposes a great deal of prior work (Agre 1994). The language and practices of database design do not reflect this work, for the simple reason that it is someone else's job. Databases receive data, and it is parsimonious to describe the various data elements in a straightforward fashion as proxies that map a preexisting reality. A database designer might be told that actions or statuses fall into certain discrete categories, for example, without needing to know how that categorization is performed in real life.

The space between representation and reality does sometimes become visible in database designers' disciplinary texts. Simsion's outstanding data modeling text, for example, points out that the designer must often choose whether a given concept is to be understood as an entity or as a relationship, and he warns against imagining that the answer can be read straight off of the underlying reality:

If we think of the real world as being naturally preclassified into entities and relationships, and our job as one of analysis and documentation, then we are in trouble. On the other hand, if we see ourselves as designers who can choose the most useful representation, then this classification into entities and relationships is a legitimate part of our task.

Some in the academic world choose the first option: that there are entities and relationships "out there" that we need to document consistently. When reading the literature, watch out for this assumption -- it isn't always explicitly stated. (Simsion 1994, p. 93)

Simsion is referring here to the entity-relationship approach's distinction between entities and records, as well as its insistence on giving priority to entities as pre-given features of the business. Nonetheless, he regards the designer's job as a choice among equally objective representation schemes:
It is helpful to think of E-R modeling as "putting a grid on the world": we are trying to come up with a set of non-overlapping categories so that each fact in our world fits into one category only. Different modelers will choose differently shaped grids to achieve the same purpose. Current business terminology is invariably a powerful influence, but we still have room to select, clarify, and depart from this. (p. 80)
Simsion's text provides a valuable record of database designers' collective experience. Having run up against a certain pattern of difficulty, it is possible to warn future practitioners against the errors that caused it. He warns, for example, that commonly used business terms often make poor names for entities in a data model because these terms may have accumulated a variety of context-dependent meanings that ought to be mapped onto several distinct categories of data (p. 64). These warnings outline the contours of the database designer's epistemological standpoint; they reflect the manner in which problems become visible from that particular location in the organizational and disciplinary division of labor.

This effect is most instructive in the case of the designer's choice of primary keys for a database. The primary keys are those columns in a given table (i.e., those attributes of a represented entity) that serve to identify uniquely the entity instance represented by a separate row in the table. Historically, the notion that these keys are plural derives from practices such as identifying individual human beings in terms of their names and dates-of-birth. Paper forms, for example, commonly ask for an individual's date-of-birth in order to serve as a "tie-breaker" in cases when two people have the same name. This practice is deeply entrenched in the profession, not least because, in the normal course of business, queries to databases tend to employ these "natural" keys. (The effect reinforces itself: the use of date-of-birth as an identifier in existing databases requires it to be collected, and then its availability facilitates its use as an identifier in future databases.) Nonetheless, Simsion argues against the practice. Some of his arguments are more aesthetic than practical: it is hardly good engineering, he suggests on pp. 202 and 205, to rely on a probabilistic assurance of having gotten the right record. A more clear-cut problem can arise when the scope of a system is broadened post hoc, after the database has been designed; a choice of keys for the narrower range of things might not suffice for the broader range (p. 204). His strongest argument, though, is that foreign keys -- that is, keys whose values are assigned by someone besides the database designer -- can change. A person might change her name, or her date-of-birth might be discovered to be in error. Changing existing online records to reflect the new values will be hard enough, given that the primary key may be used to identify the individual in numerous tables. But it may be impossible to update records that have been archived on fixed media. Simsion says on p. 206: "[the] foreign key maintenance problem is usually the most effective method of convincing programmers and physical database designers of the need for stable primary keys".

The point has significant consequences for privacy. The mirror metaphor, as well as the conceptual and linguistic tendency to conflate records with the entities they represent, makes it seem reasonable to employ a "natural" identifier such as name and date-of-birth as the primary key. But, Simsion suggests on p. 202, a cold look at the technical requirements for a primary key provides a compelling case for the use of "surrogate keys" -- arbitrary numbers used solely to signify an individual's existence and not its other attributes. So long as representations and reality are conflated, it is difficult to comprehend privacy in any terms other than control over access to individually identified data records. Practitioners' experiences, though, have led to a tacit and indirect awareness of the necessity of cleanly distinguishing representation and reality. Principled application of data modeling methods and surrogate keys, it must be said, is hardly the norm in current industrial practice. Nonetheless, consistent use of surrogate keys to identify data subjects affords other technical options for protecting privacy.

New Privacy Strategies

At the conclusion of their 1996 meeting in Manchester, England, the European Union Data Commisioners released a statement reporting their decision to "work over the next year on Privacy Enhancing Technologies to promote these techniques for reducing the extent to which personally identifiable information is used in information systems, with a view to developing pilot projects which can be examined at their next annual meeting and used as models to promote the further adoption of these techniques in industry, commerce and public administration".

The foregoing analyses help explain why the data commissioners' initiative is possible in theory, and why it is exceedingly difficult in practice. Ever since Sweden passed the first data-protection law in 1973, privacy policies have followed a common model grounded in the Fair Information Practices (Westin 1967; Rule 1974, 1980): presupposing the existence of computerized data records that identify individuals, governments have sought to regulate the conditions under which such records are created, used, and propagated (Flaherty 1989; Bennett 1992).

The data commissioners' analysis of privacy-enhancing technologies (PETs) relied upon a study by the data commissioners of Ontario and the Netherlands on technologies of anonymity (Information and Privacy Commissioner and Registratiekamer 1995; see also Burkert's chapter in this volume). This study suggested the use of a system element called an "identity protector" to shield individual identities from organizations holding data records about them. The underlying technology for identity protection was developed in large part by Chaum (1985, 1986, 1990, 1992; see also Chaum, Fiat, and Naor 1988). Chaum observes that data records cannot cause privacy problems for individuals unless they can be traced back to the individuals whose lives they represent. So long as databases identify individuals by a universal identifier such as a name or a government-issued identity number, records can easily be propagated and merged, and thus employed for secondary purposes to the individual's detriment. Chaum's alternative approach is to employ digital pseudonyms, also called pseudoidentifiers. Individuals wishing to transact business with an organization need not identify themselves. Instead they present proof that they own a particular pseudonym, and then they use a cryptographic protocol to present "credentials" (Chaum 1985) that warrant that some relevant predicate holds (for example, being old enough to purchase alcoholic drinks) without revealing the information upon which the credential is based (i.e., one's precise age). The purpose of the identity protector is to manage and authenticate these pseudonyms, which are then used as surrogate keys in the relevant organizational databases. Figure 6 illustrates one possible configuration of an identity-protecting architecture. In this case, the identity protector is interposed between a system user and a variety of "pseudo-domains", each of which employs a different pseudonym to identify the user. By providing a different pseudonym to each organization, the user can control which personal information moves across organizational boundaries (Chaum 1990). Other configurations are possible, depending on where the sensitive identification is stored, which parts of the system actually need to know the user's identity, and what kind of auditability might be required. For example, the Air Resources Board's scheme to detect drivers who fail to repair their emissions systems, discussed at the outset, could employ a kind of "identity escrow" that discloses the identity of a driver (or the car) only when fault codes consistently show up over a certain period.

Despite their complexity, schemes based on digital pseudonyms offer certain advantages beyond the protection of individual privacy. Because databases indexed by pseudonyms no longer contain individually identifiable information, they need not be secured as tightly. Information can also be more readily transferred across organizational boundaries for purposes such as statistical research. Authentication poses a problem for these schemes, however, and the most appropriate method of authentication will depend on the particulars of each application. Photographic or biometric identification of individuals (Clarke 1994) would seem to defeat the whole purpose of an anonymous system. Smart cards carry the risk of loss or theft. Users probably cannot be expected to remember large numbers of distinct passwords. Technologies based on biometric encryption, though, may be useful for pseudonymous authentication in certain applications. In the biometric encryption system marketed by Mytec Technologies of Toronto, individuals initiate a relationship with a given organization by permitting a Mytec device to encode a known data string using an optically transformed fingerprint image. On subsequent occasions, they are able to initiate a transaction by placing a finger on a scanning device to decrypt the encoded information. The organization, meanwhile, does not retain an image of the individual's fingerprint or any other individually identifying information.

Encouraging adoption of such technologies, unfortunately, requires more than technical existence proofs. One significant issue is trust in the system itself. After all, the system could also be used as a traditional biometric authentication system by encoding a universal identifier; an organization that simply claims to be using biometric encryption is therefore not necessarily protecting anybody's privacy. The issue is already being tested in Ontario, where a social activist group, the Guelph Coalition Against the Cuts (1996), has begun a campaign against a provincial government plan to employ biometric encryption in distributing social assistance payments. They suggest that "a multi-billion-dollar corporation making money by treating the poor like criminals" provides a suitable symbol of the conservative government's cuts in social welfare programs. Fingerprinting and fingerscanning systems for welfare recipients have, after all, been implemented in the United States; the issue here is whether the Ontario system based on biometric encryption deserves to be assimilated to the police-state metaphors that have long shaped public understanding of universal identification. It is conceivable that any misunderstandings could be repaired through a suitable public communication campaign. One potential model might be the successful campaign that Pacific Bell conducted in the spring of 1996 as a condition of its introduction of Caller ID service to California. The issues around pseudoidentity, however, are much more technical, and the technology itself is counterintuitive even to computer professionals.

Indeed, the force of habit among designers is another significant obstacle to the adoption of PETs. So long as the language of computer system design tends to blur the difference between representations and reality, and treats data records as mirror images of the world, the firewall that PETs provide for individual identity will remain nearly unthinkable -- designers will often simply assume that records pertaining to individuals can be traced back to them. The problem does not lie in the practices of database design, which may evolve toward the use of identifers that can equally easily be universal or pseudonymous -- in that limited sense, the methods of computer system design do not, as social theorists have often assumed, inherently lead to the invasion of privacy. Instead, privacy invasion results from the way in which the technical methods are customarily applied. The necessary change in customs can be encouraged through model programs and exhortation from policymakers. Ultimately, though, it will be necessary to revise the training of system designers to reflect the emergence of new technical options. Lessons will be needed in cryptography and protocols for the management of pseudonyms, of course, but other necessary revisions are less obvious. The examples provided in database texts, for example, almost invariably identify human beings by their names, and they rarely provide any sense of the moral issues that are at stake in the selection of primary keys.

Much experience will have to accumulate before PETs can be integrated into the wide variety of institutions and concrete life situations to which they are applicable in theory (cf. Bijker and Law 1992). Troubles arise immediately when organizational relationships are not confined to digital media. Customer service telephone numbers, for example, have typically required individuals to identify themselves, and telephone interactions based on pseudonyms will inevitably be clumsy. Customers who enjoy the record-keeping benefits of periodic statements (from credit cards, banks, the phone company, and now automatic toll-collection systems) will require some way of obtaining such statements without disclosing their name and mailing address.

Perhaps the most significant accomplishment of PETs to date is the beginnings in a shift of imagination. When records of personal information can always be traced back to the individual whose life they represent, privacy interests trade off against system functionality. The result, as the historical record plainly shows, is that privacy interests almost invariably lose out in the end. Data-protection regulation can contain the abuse of personal information within this framework, but it cannot contain the proliferation of technologies that create and use personal information for ever broader uses. Markets in privacy can operate at the boundaries of the system, for example to express customer choice about secondary uses of transaction-generated information, but such markets require that customers be able to estimate the disutility of secondary use despite the enormous credit-assignment problem. (The issue is one of transparency: "How did they get my name?") PETs, however, promise to provide data subjects with much more detailed control over the use of their information, as well as greatly lowering the price of refusing to disclose it. Whether that promise is fulfilled, however, depends on a great diversity of factors.


I hope to have suggested the utility of historical investigation of computing as a representational practice. A brief chapter cannot survey the whole field of computer science or even the whole subdiscipline of systems analysis; numerous chapters in the complex history of data have been glossed over, and relevant areas such as data communications and security have been left out entirely. Nonetheless, some clear trends can be discerned. At stake is the sense in which a technical field has a history: what it inherits from past practice, how this inheritance is handed down, the collective thinking through which the field evolves, and how all of this is shaped by the institutional contexts within which the work occurs.

To answer these questions, one might suggest that privacy problems have arisen through the application of industrial methods to nonindustrial spheres of life, where normative relations of representation and control are different. But that statement alone is too simple. Technical work is not indifferent to the contexts in which it is applied; quite the contrary, it is continually confronted by the practical problems that arise in pursuing instrumental goals in particular concrete settings. Another part of the problem, then, is the manner in which "problems" arise in the course of practitioners' work, and how these problems are understood. Database designers, for example, have been forced to clarify their methods on numerous occasions when existing databases have been used for new and unforeseen purposes.

Yet these mechanisms of practical feedback were evidently not adequate to stimulate the invention or ready adoption of methods that decouple data records from human identity. The mathematicians who did invent such methods in the 1980s were explicitly motivated by a desire to protect privacy, and they have faced an uphill fight in getting their ideas adopted. Much of this fight, of course, has been overtly political (see Phillips's chapter in this book). Organizations with pecuniary interests in the secondary use of personal information will presumably not be enthusiastic about the new technologies. But on another level, I want to suggest, the fight concerns basic understandings of representation and its place in human life. Information is not an industrial material or a mirror of a pre-given reality. It is, quite the contrary, something deeply bound up with the material practices by which people organize their lives together. Computer systems design will only escape its association with social control once it cultivates an awareness of those material practices and the values they embody.


One version of this paper was presented at the University of Toronto, where I benefited from the comments of Andrew Clement. Another version was presented at AT&T Labs, where Paul Resnick, Joel Reidenberg, and several others offered helpful comments. Michael Chui and Roger Clarke kindly offered suggestions on a draft.


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