It is difficult, however, to avoid the sense that the most sympathetic reader will struggle to admire the authors as much as they appear to admire themselves. "An explanatory note" at the beginning of the book explains Dubner's view that "many economists" speak "English as if it were a fourth or fifth language" and Levitt's sense that the "thinking" of "many journalists" is not "very . . . robust, as an economist might say" (x, ellipsis in original). Happily for us, the note explains, we are reading the work of exceptions to these rules: "Levitt decided that Dubner wasn't a complete idiot. And Dubner found that Levitt wasn't a human slide rule" (x).
The authors' patting of their own backs will put off some readers, but it should not take away from the insights of the book. I mention it because this is not merely a matter of tone: in fact, authorial self-congratulation is the thesis of the book. One of the great marketing triumphs of Freakonomics is the ability of the authors to persuade many readers that the lack of an overarching argument is a feature, not a bug--the explanatory note ends with a philosopher asking about Levitt, "Why does he need to have a unifying theme? Maybe he's going to be one of these people who's so talented he doesn't need one" (2). Or as Malcolm Gladwell puts it on the back cover, "Steven Levitt has the most interesting mind in America." The same idea is reflected in the title: "freakonomics" is a nonsense word, a term used in the book and even more on the authors' blog to stand roughly for stuff that Levitt has argued or that Levitt and Dubner find interesting. Returning to the book's lack of a unifying theme in an epilogue, Levitt and Dubner do make a claim for a "common thread" of "thinking sensibly about how people behave in the real world," and they suggest that readers "might become more skeptical of conventional wisdom" for having read the book (205).
It is hard to argue with such broad claims, but it is worth pointing out that other books have similarly challenged conventional wisdom in ways that more actively assisted readers with their own investigations. Leaving aside the philosophical heavyweights in the skeptical line--Plato's Socrates and Hume, among many others--consider a few recent examples. When Bill James published his Baseball Abstract, he made claims like Levitt and Dubner's for the value of a general skepticism of conventional wisdom. Though James's works are not unified by theme, they do not take on all of everyday life, and focus on baseball allowed a new kind of analysis to flourish after James's example--and James's unconventional wisdom has taken hold, even as many later analysts have revised the specifics of James's claims. Or when Thomas Gilovich published How We Know What Isn't So: The Fallibility of Human Reason in Everyday Life
There is no equivalent framework in Freakonomics. The authors call this a lack of a unifying theme, but lack of thematic unity is a literary defect. The limitations of Freakonomics lie rather in the absence of larger scientific ideas: Levitt's argument about the relationship between legal abortion and crime rates is an argument only about that issue. The arguments of Freakonomics apply so narrowly that, while I do recommend reading the book for its key points--especially chapters three through five, on the economics of drug dealing, abortion and crime rates, and advice given to new parents, respectively--I cannot recommend reading it before the best works of the other authors I have mentioned, from Plato to Gladwell.