But how do the fashionable decide what the next big thing is? Or perhaps more to the point: how does the fashion industry convey to their consumers what they should be wearing? How does the industry “anchor” the consumers in this season’s fashions? This is where copying comes in. If all the designers are showing baby doll dresses in the spring of 2006, then there’s a good chance that is what everybody will be wearing by the summer of 2006.

Mr. Raustiala and Mr. Sprigman argue that the lack of intellectual property protection actually promotes the functioning of the industry. If the extension of copyright to fashion prevented clothes manufacturers from copying each other, the industry would be ceding a major role to the lawyers and become much less creative. We’d see the same thing year after year. In other words, women’s fashion would look much more like men’s fashions — boring, boring, boring.

Since I have the same fashion sense that most economists have — that is, none whatsoever — I cannot attest to the accuracy of the law professors’ description of the fashion industry. But it is consistent with other examples of what happens when there is no intellectual property protection.

The United States did not protect copyrights of foreign authors until 1891, since it was just too tempting to ride free on the production of those great 19th-century British authors. Clipper ships used to carry copies of Charles Dickens’s latest book to America, where it was quickly rushed into print by dozens of printers and sold for next to nothing.

Critics complained that these hastily produced books were poorly printed and cheaply manufactured. That may have been bad for books, but it is not such a big deal for that cheap, but fashionable hoodie sweatshirt your teenage son bought a few months ago, since he isn’t going to wear it next season anyway.

The United States started recognizing international copyright in 1891 partly to protect American writers from cheap foreign competition like the Dickens volumes. This was almost certainly the right thing to do, particularly since copyrights held by Americans received reciprocal recognition abroad.

But not every industry necessarily benefits from strong intellectual property protection. In some cases, it appears that lack of protection can lead to a more vibrant and dynamic industry.