"Mirror worlds were not supposed to be an escape from reality; they were supposed to reflect reality. A modern-day city generates plumes of data the way 19th-century industrial towns generated smoke. There are block-by-block crime statistics, test scores for every student in every school, traffic reports updated by the second, demographic profiles by zip code, and so on. All of those numbers exist somewhere in cyberspace, but finding them is next to impossible. Gelernter envisioned a centralized repository for all this data, a virtual reconstruction of a space that would showcase everything going on in reality. Gelernter's simulated worlds were going to be mirrors. By comparison, the simulations we have now are fantasy islands.

In a true mirror world, data would be mapped onto recognizable shapes from real life. For instance, to find information on a local hospital, you would locate the building on a computerized map and click on it with an "inspector" tool. Within seconds, the big-picture data about the facility would come into focus: number of patients and doctors, annual budget, how many patients died in operating rooms last year, and more. If you were looking for more specific information—say you were considering giving birth at the hospital—you could zoom in to the obstetrics department, where you would see data on such subjects as successful births, premature babies, and stillborns. Information about how the hospital connects to the wider city—what Gelernter calls topsight—could be had by zooming out."

"My life, like your life, is a series of events in time, with a past, present, and future," Gelernter says, sitting in a conference room in the New Haven offices of Mirror Worlds Inc., the software company he cofounded. "And that's the way my software ought to look. The mirror worlds approach to organizing information is based on reality, as opposed to an engineer's or a computer scientist's fantasy. I don't want my personal life to be stored in an arbitrary UNIX file tree; I want it to be life-shaped—the shape of the way I live it." He gestures out the window, to the stately spires and ivy-covered buildings of the Yale campus. "I want information on New Haven to be New Haven-shaped, not in 10,000 separate databases."