Friday, May 18, 2007

What It's About 2: More is Different

In 1972, the physicist P. W. Anderson published an essay titled "More is Different," arguing against the idea of scientific reductionism (Science 177, no. 4047).

The main fallacy in this kind of thinking is that the reductionist hypothesis does not by any means imply a 'constructionist' one: The ability to reduce everything to simple fundamental laws does not imply the ability to start from those laws and reconstruct the universe. ... The constructionist hypothesis breaks down when confronted with the twin difficulties of scale and complexity. The behavior of large and complex aggregates of elementary particles, it turns out, is not to be understood in terms of a simple extrapolation of the properties of a few particles. Instead, at each level of complexity entirely new properties appear, and the understanding of the new behaviors requires research which I think is as fundamental in its nature as any other.

This is the second sense in which digital history is not about computers. Taken by itself (or in conjunction with a user and stand-alone application software), the properties of a single computer tell us almost nothing about the properties and possibilities of densely interconnected networks of people, machines and software. Researchers in artificial life and related fields have shown that routine interactions among simple, identical agents can result in complex and unpredictable swarm dynamics. The heterogeneous assemblages that provide a context for digital history are far richer, perhaps best captured with the metaphor of information ecologies.

Having more gives you completely different capabilities. Take the example of Amazon's database of customer information. When you look at an item, the system can provide you with pointers to related items: "people who looked at / bought this also looked at / bought x, y, z." As you look at and buy items, the system becomes smarter. Idiosyncracies of individual browsing or purchasing are ironed out as more data are collected. Over time, new associations may develop and old ones disappear, providing insight into historical trends. The Amazon book database is already so powerful that no humanist can afford to ignore it, but the strength of this approach is not limited to commercial applications. Suppose that scholarly books and articles were indexed in a similar way: "people who looked at / cited this also looked at / cited x, y, z." It becomes trivial to do kinds of literature review that are normally very difficult. One of these is to assess the downstream impact of a given work: which works cite this one? Another is to find related but isolated research groups, who may be citing an overlapping literature but are apparently unaware of one another's work.

Having more changes our ideas of what history and memory are. Roy Rosenzweig's essay on scarcity and abundance should be required reading for all historians. I've already written about information costs, so I won't go into detail here, except to say that historical projects have largely been defined by what we can't find or know, and that's about to change. Having nearly frictionless access to vast amounts of source material makes it possible to undertake projects that hinge on attested, but very-low-frequency evidence. Having more of everything also means that attention becomes a scarce resource. As scholars, our reputations and careers are increasingly shaped by the logic of the gift.

Finally, more is about to become an awful lot more. Technologies like RFID and MEMS make it possible to create vast sensor networks that continuously record data in unimaginable quantities, or that can track the history of practically any object of interest. CARPE researchers study the capture, archival and retrieval of personal experiences across a lifetime. If you thought Samuel Pepys left a lot of material, you haven't seen anything yet.

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