I read recently that someone was proposing to abolish funding for libraries, on the grounds that they are not needed now that we have the internet around. It is true that much reference information is available on the internet, at significantly greater convenience than going to a library. However, the suggestion overlooks the fact that many people rely on the library for their internet access. It also misses the obvious point that libraries still lend out books, and very few new books are available for free online.
I think the suggestion is flawed in thinking that the internet is (yet) a replacement for libraries, but it is worth considering on its own merits. Why do we need libraries? The obvious disadvantage to libraries is that they discourage people from buying books. I occasionally read about declining book sales in America, and surely having nice libraries only contributes to the trend. I am certain that I have read some books in the library that I would otherwise have bought.
Of course, that's not the end of it. I have also read some books in the library that I would not have bought, so the amount of "social information"(1) has been increased. Moreover, some people can scarcely afford books at all, so libraries perform a useful function in bringing knowledge to them, even if it means that more affluent people buy fewer books, decreasing the total amount of book sales. The decrease in book sales is also partially offset by the price that publishers charge libraries, which is usually significantly higher than the price they charge individuals. I wish I knew more about the different rates; I can't say whether the higher price is intended to cover completely lost book sales, or if it is just a partial compensation.
Then, too, many academic books (including both of mine) wouldn't be bought at all if it weren't for libraries. It's typical nowadays for an academic book to retain for over $100, sometimes over $200 -- and remember, I'm not talking about coffee table books, just books with lots of words and footnotes. No one in his right mind would buy that for his personal collection. Arguably, these books shouldn't be published; I've certainly read some books that I can't imagine anyone ever using. Since the decision is up to the collection managers in libraries, rather than to the market, it's difficult to tell whether the library is making the right choice in buying obscure books. If publishers didn't have the library market, would they be able to produce versions cheap enough for scholars to buy on their own?
Libraries seem to provide social value, and I certainly love them. I've spent a lot of time either working in them or visiting them, and I still get a thrill whenever I walk into a library and think of all the books for me to read. I even met my wife in the library. I'm not sure that they're a good investment, however. If people had to buy books that they wanted to read, publishers would certain sell a lot more books; that means prices would be lower, and more books would be published that are rejected today. One difficulty is that it is impossible to stop people from sharing books. This is what they did before public libraries were common: a patron with a large collection would allow scholars to come use his books. (Cardinal Mazarin, the subject of my first book, in fact had one of the largest collections in Europe, and he donated it to the crown to form what became the Bibliothèque Nationale.) So getting rid of public libraries might not mean the end of book borrowing in general; it could just move it to the private market.
This issue is becoming ever more relevant with the internet, because it is easier than ever to copy a book virtually for free and give it to someone else. You can already download thousands of books whose copyright has expired at the Gutenberg Project. This doesn't completely eliminate the need for books (reading paper is still much more convenient, and easier, that reading a computer screen), but we're getting close. On one hand, this is obviously a good thing: the authors, probably all long since dead, lose nothing, and individuals gain a great amount by having access to more books. On the other hand, what is the incentive to write books if no one is going to pay for them? Will authors have to be funded by patrons -- wealthy individuals or institutions -- as in the past? Libraries belong in the past in one sense -- they house printed books that are becoming easily available in other formats -- but they belong to the future in another sense -- they suggest the apparent difficulty that the spread of knowledge seems to discourage its production.
1) That is, the sum of all the information in everyone's heads (so that the same information in two heads counts twice), or, to put it in units, the amount of “person-information.”