to believe that each of these topics is rich and connected to how a city works. Work, infrastructure, and worship would seem to be fundamental components of a civilization. But what is most striking is how these topics are by the way encountered in the documentation work.
What We Might Know about a City
In The Critique of Pure Reason (1781), Kant took on the skeptical tradition that denies that we might have complete and total knowledge of the world, by making clear what we might mean by scientific knowledge. Such knowledge is a product of our faculties and their capacities, and, as important, the logic of our thoughtways. We cannot have knowledge of things in themselves, only as they are for us. There are limits to what we can know, limits to certainty and completeness. By staying within those bounds we can have scientific knowledge.
What can we know about a city and its sensorium? I am here concerned with aspects of the city that are available to sight and sound, although smell, taste, and touch often enhance those senses. It is through tomography that such knowledge is evidenced. Tomography is many slices or aspects or perspectives on the world, claiming that they are picturing the same thing, albeit from different angles. In effect, it is a claim that there is unity in multiplicity, identity in manifolds.5 Whether that tomogram is of the brain in a CAT scan or of the heart in an echocardiogram, or of the facades of storefront houses of worship in Los Angeles, what we are offered is a multiplicity of images or videos about the same thing, or so we initially believe. We employ those slices to articulate a more detailed understanding of that thing, whatever it is. We start out with a notion of that unity or identity or thing, and through that multiplicity we modify that notion so that it can more adequately provide for that variety in that multiplicity, so that the notion is more accommodating.6 We have some idea of what we are looking at already (the particular organ or thing or notion) as we examine each image separately; we are filling in the details, figuring out, an imaginative draftsmanship. Tomography allows for, it presumes, such identity in manifolds, many images showing us a world or an object as we encounter it from different aspects.
More generally, the project is to document a city in terms of multiple slices in space and in time and in type (hence tomography), a unity in that multiplicity of aspectival variations (a phenomenology), showing how people, machinery, and nature work together or coordinate to get the city’s work done (a choreography). Denis Diderot (circa 1760), Charles Marville (circa 1860), and Eugène Atget (circa 1915) once did much the same for Paris, in systematic surveys and multiples. Ordinary everyday life, in its tissue of negligible detail, is rich and deep, and through tomography we discover that detail in the context of an encompassing understanding of the whole.7
The cinematic arts and opera are suggestive models. The cinematic arts are concerned with multiple slices and cuts, compositing, storytelling, and screen language.8 In opera, the claim is that music, sound, and visual action form an indissoluble whole. In both cases there is also the claim that repeated viewings or performances are rewarding, your noticing and appreciating new things each time around as well as recalling what you have already taken in, perhaps radically revising your understanding of the work. Both also allow for multiple scenes on the same screen or proscenium, each playing against the other.9
Slicing Up a City
A tomograph is a knifelike device meant to section or cut thin slices of tissue. Computer-aided tomography uses thin, almost one-dimensional X-ray images, or “pencils,” of an object to construct a two-dimensional image of that slice of an object, and presumably those slices can then be fitted together to get a three-dimensional model.
We slice up a city or a type of phenomenon or a process through multiple aspects: photographs of the facades of many storefront churches allow us to appreciate urban religiosity as a diversely manifested phenomenon; photographs of the merchandise displays in ethnic markets show the variety and the similarities of urban subgroups; and photographs or videos of the various aspects of the casting operation in a foundry (Figure 6), forming an album, provide what we need to imagine the whole process.
Most urban situations are complex and varied and have many temporal aspects. To document a street market we need images from various perspectives but also of different sorts of transactions, of the insides of the booths, at various times of the day or week, and so forth. In addition it would help to interview the participants to discover their accounts of what is going on—in effect, additional slices or aspects.
We might capture such a situation or phenomenon one at a time, using still photography or audio recording. But now there are inexpensive sensors available and sufficiently ubiquitous to document urban life more pervasively, to provide a very large number of slices or aspects—unlike our experience in 1963 that resulted in just one movie of President Kennedy being assassinated. Namely, video-equipped cell phones are such sensors, and they are carried about all the time. We might imagine a swarm of such users (that is, crowd sourcing) documenting an event or situation, each from his or her own perspective or interest (Figure 5).10
Such a corpus of images, videos, and sound clips, less as a set of disjointed pieces of a puzzle and more as a series of differently detailed renditions with the documents labeled and organized by location and time and perspective, allow us to better know the whole that is here presented aspectivally.11 Ideally, we have lived in this place or we have already done fieldwork ourselves, so we have some idea of what that urban world is like. We start out with a sense of what there is in a city and can fill in and modify our initial notions, check them out, and learn more. Urban tomography leads to a fuller sense of place and activity.
The actual city is an archive of repeated forms and structures and designs allowed to age, repair, and renew themselves. The ubiquity and variety of these forms in a city are products of the political economy of real estate development and decay, the rise and relative decline of neighborhoods under the influence of larger societal forces, and a politics of public choice for support and subsidy.
So the city itself is an archive of its past, much as a population is an archive of its past (as the evolutionary biologist would say). However built and for whatever reason, much of the built environment lasts well beyond its planned lifetime, perhaps rebuilt and repurposed. Speculative building of a large number of similar structures, whether they be stores or homes or industrial buildings or office buildings or factories, means that many structures have many identical representatives. In time each particular building is altered to suit its current or prospective owners; some buildings are destroyed, others restored. (The usual example is a planned urban development, as in a Levittown, fifty years after opening.) New uses make what once appeared to be doomed neighborhoods or building types into lively, productive, and economically viable places and enterprises. A real estate market that allows for these processes will eventually produce a city that has a wide variety of what were once similar buildings and uses, likely to be spread throughout the city although not in all areas. What was once repetitive and the same becomes variegated and diverse. Development alters the consequences of genetic endowments. Moreover, new uses tend to be agglomerated in certain areas, there being good reasons to have competing enterprises located near each other. Yet those enterprises also specialize, providing for a wide range of niches. So might the story of urban economies be told. The storefront houses of worship we see when we drive around town are products of just those processes that have built and rebuilt cities, especially since industrialization.
What an archive provides, what a built city provides, is a range of possibilities and instances, which then become inhabited in ways we do not foresee. The artist Frank Stella made a series of works (sculptures, paintings, prints), one or more for each chapter of Moby-Dick (which has 136 chapters).12 Even knowing Moby-Dick well and Stella’s previous works, it would be difficult to predict how each chapter
