Browsable stacks – shelves of books that you can actually look at, pull of the shelf, read a while, and put back. They’re wonderful. Folger readers regularly comment on the fact that they can walk freely through the stacks of the secondary collection, which in our case means books published after 1830. That collection is arranged by Library of Congress call number, and many know the system intuitively after years of library work. (I frequently find myself in the PRs and PNs.)
Recently I was looking through section PN6420.T5 for books on early modern proverbs, a topic I have been writing about for years. I was looking for Morris Palmer Tilley’s collection, A Dictionary of Proverbs in England in the Sixteenth and Seventeenth Centuries (Michigan: University of Michigan Press, 1950). There it was, right where it was supposed to be: a landmark piece of scholarship that is the first source for anyone interested in the topic. Yet this was only the first stop. On the shelves above and below this important source were about 30 other books on the subject, some of which I began to explore. Some very useful books turned up next to the one I had initially intended to find. Some of them have even turned up in my footnotes, the ultimate test, perhaps, of a book’s usefulness to a scholar.
Stack browsers are on the lookout for this kind of happy accident. You go into the stacks looking for this book, but another, more interesting, happens to be nearby. Now you can have a look, nibble around the edges of the promising title, which is an excellent form of procrastination if you are stuck or unready to begin writing. Having done my share of meandering in open stacks, I am intrigued when readers describe these moments of discovery – which after all are part of the natural progression of research – as happy accidents or the products of chance. Aren’t accidents things that you cannot, by definition, bring about or encourage?
The fact remains that libraries is set up to make such accidents happen. They arrange books on the shelves in a certain way – not at random, but on a plan designed to increase the likelihood that, nearby the book you think you want, there will be others you also want to read. When someone says, “and then I happened upon this great book,” they may be describing the advantages of the library’s structured arrangement of books by (say) subject matter. Partly an effect of a classification system, partly one of the physical arrangement of the space, Libraries are designed to promote “lucky finds.”
Such “encouragable accidents” are really the consequence of a simple principle that governs the entire space of the library: that of structured adjacency. As I will try to show in a moment, this principle can be seen at work in both the physical spaces of the stacks and the digital discovery spaces designed to give us access to the collection. The root of the word adjacency is the Latin verb jacere, which means to throw. When books appear side by side on a library shelf, their adjacency is not a product of chance: they have been placed (hopefully not thrown) together so that one is next to another of similar kind. How might one structure such adjacencies? One technique would be to shelve books by size. In some medieval monasteries, books of a similar size were placed on the same shelf. In addition to saving shelf space (think about it), this arrangement located collection access in the mind of the librarian or keeper who knew where different titles were. These collections weren’t designed to be browsed, so the principle made sense.
Now think of a modern, browsable stack of books arranged along the Library of Congress call number model. Here the principle of access exists in two places: the launching point of the card catalogue (which tells you where in the stacks to start looking) and then on the shelves themselves, where books on similar subjects are grouped together. The idea here is to use the intellectual scaffolding of subject cataloguing to structure the physical space of the collection. With respect to subject, physical adjacencies on the shelf become virtuous instead of vicious.
What is a virtuous adjacency? It is a collocation of two items likely to appeal to any-user-whatever whose item search is itself structured along principles which the cataloguing supports: usually author, date, title, subject, although there are many other forms of search. It doesn’t matter who you are or how deep your knowledge of the subject is: if you know enough to find one book on proverbs, you can find many in the Library of Congress system, because you are helped along by the arrangement in the physical space of the library. That arrangement is principled and intentional. It is virtuous.
But every virtuous adjacency can quickly become vicious, and this is because virtue (as I’m calling it) resides in the principles that inform any given reader’s search for a book. Suppose I know about Tilley’s book on proverbs, and I know it by title. Once I am pointed to that book by the catalogue, I go and look at it, and I see some terrific proverbs about apes, for example, “To make her husband her ape.” I start to think about this. Maybe what I’m really interested in is how the behavior of apes helps people think about the nature of mimicry and mimesis in the early modern period. (Early modern references to apes are often veiled references to the mimetic power of artists, who “ape” nature.)
Now the principle that governs the space flips. What I need to do is go to H. W. Janson’s magnificent Apes and Ape Lore in the Middle Ages and Renaissance, which has the call number GR730.A6 J3. What made the first adjacency surrounding “books about proverbs” virtuous was the collocation of books in space by subject. That was where the manufactured serendipity happened. But now that very principle of adjacency has become an impediment – it has become vicious – because Tilley is not surrounded by books about apes. I could search again under the latter subject, but that would not be adjacency, it would be search. We advert to catalogues in order to re-orient ourselves within the physical universe of books-on-shelves, or the virtual space of digital collections. But we cannot simply wander into that next thing that meets our new interest. To do this, I really would have to be lucky: “Oh look, there’s Jansen’s book on apes, just lying across the aisle….”
The moral of this story – or is it the proverb? – is that “every virtuous adjacency is also vicious.” When it comes to the arrangement of books, virtue is relative: it depends upon what the researcher thinks he or she is looking for, a thinking that often changes in the course of research. Once you’ve flipped from proverbs to apes, the physical arrangement of books on shelves is not going to help you. The virtuous arrangement that allowed you to lay your hands on that first book (“hey, my favorite book on proverbs!”) is now working against you (“shouldn’t I be looking at books about apes?”).
As we gain greater access to the contents of books; as digitized books and their machine actionable contents become more and more arrangeable with the assistance of mathematical principles like the topic model, the physical space of search is being transformed into something more plastic, even Borgesian. While the physical space of the library cannot be re-plotted whenever the research forks out onto another garden path, researchers have more options in the virtual space of text searching to find cut-throughs. There is a problem here, of course, which is that in such a virtual world of association, there are infinite pathways for association. It becomes more challenging to figure out where to go next when you could go anywhere.
But there may be other ways to multiply virtuous pairings given the tools that librarians of the future will create. Instead of starting with Tilly and then hoping that I’ll be lucky enough to bump into Jansen, I might rely on my mobile device to reach into the contents of the book I’m interested in now and, based on a principle of adjacency I supply, rearrange all the books in the library around that first book in concentric layers of immediacy of different types – layers that might allow readers to move from one virtuous adjacency to the next. There is no way around the virtuous/vicious symmetry, since it is precisely that symmetry which makes research necessary: in exploring the connection between these five books on proverbs, you are giving up the opportunity to think about that other, really, really good book about apes. (You can tell I wish I’d found Jansen earlier.) What makes an adjacency for one research task virtuous makes that adjacency vicious for the next.
That’s why answers to research questions do not turn up instantly. You have to decide when to shift directions, and the physical layout of library stacks according to a single principle of adjacency (e.g., subject cataloguing) is going to sustain some inquiries while simultaneously shutting down others. No amount of dynamic text search is going to put an end to the virtuous/vicious circle: their pairing represents a real constraint on knowledge – the fact that thinking is progressive, and moves on discrete pathways – rather than a technological or physical limitation to be overcome.
That is not to say that there aren’t new ways of mapping adjacencies among digitized texts. Abstract models of the contents of books such as topic models, however, do offer us other pathways in the research process; they are an additional principle of adjacency that we can invoke if we don’t want to “jump the hedge” by consulting a book’s footnotes (say) and then searching for new items based on the titles referenced there. (On topic models, see Ted Underwood’s very helpful blog post.) We have been using topic models in the Wisconsin VEP project to look at our collections of texts, and they do seem to open up adjacencies that we would never have thought about. (An upcoming blog post will deal with the relationship between the novel and English moral philosophy.) A topic model can suggest, for any given book or passage, another book or passage that might be relevant for reasons only a user could recognize (but might not be able spontaneously to supply). As with other techniques of dimension reduction (e.g., PCA, factor analysis), there may be more topics than we can name or recognize: a topic does not become a principle of association until a human being recognizes and affirms that principle in action.
If libraries are gardens with many forking paths, the hedges that separate those paths are absolutely real. Even a fully virtual, instantly re-arrangeable virtual rendering of our shelf spaces will not put an end to vicious adjacencies, since they too will become virtuous if research takes a new turn. Our challenge is not a physical one; it’s not even computational. In a future library where any two books could be placed alongside one another in an instant, we might never find anything we want to read.
The task of library research is not simply that of poking around clusters of items on a shelf, or more grandly, finding ways of reclustering books continuously in hopes of finding the ultimate, virtuous arrangement. There is no Leibnizian, maximally virtuous arrangement of books, and never will be. (Leibniz must have hit upon this melancholy thought when he was librarian at Wolfenbuttel.)
But there are more or less definite lines of thought, each on its way to becoming other, equally definite, lines of thought. There is no point in celebrating the fact that such lines can fork off in an infinite number of directions. We know already that a researcher can only follow one of them at a time.