On the Virtue of Old Musty Tomes and Their Authors

Brad DeLong pleased me greatly by posting this fascinating list of quotations from Adam Smith a few days back. But when challenged by a reader to explain why one should ruminate on the thoughts of dead economists and philosophers, when their thought has been incorporated in and corrected by the work of subsequent thinkers, he gave this disappointing reply. The gist of DeLong’s response is that dead thinkers are like an extended circle of entertaining friends.

Well, if that’s the best reason to ponder the works of old dead dudes, then I’ll pass. I can do without the stilted language and dated examples, and my real live friends are more entertaining. But I can think of at least three better reasons to read the old economists and philosophers.

First, the notion that “all that was good in the ancients is included in the moderns” is pure hubris. It would be comforting to think that the intellectual marketplace works with perfect efficiency, that every academic debate settled is settled correctly. Comforting, but unlikely. The theories of social science are accepted and rejected as often on the basis of politics as on the basis of objective truth (even supposing there’s an objective truth to be had). The macroeconomic theory of Keynes, for instance, was accepted in large part because people were looking for escape routes from the Depression, and Keynesian theory promised one. Keynesian economics eventually died, with much credit due to the stagflation of the 1970s, and was replaced by rational expectations and real business cycle macro theories. Later, Keynes was resurrected by economists who cast his arguments (or at least his conclusions) in the form of rational-expectations-with-sticky-prices. At the risk of invoking Hegel and Marx (two old dead dudes I can pretty much do without), I would suggest social scientific thought is a dialectic, not a monotonic approach to the truth. This is not to say I don’t think there is such a thing as truth -- only that finding it is more problematic than the efficient-marketplace-of-ideas hypothesis implies.

Second, even if our new theories are more correct than the old, that doesn’t mean they’re comprehensive. Not all topics that interested the ancients have been fully explored by the moderns, as the choice of what topics to examine often follows the issues of the day. To take just one example, a coauthor and I recently wrote a largish paper on the subject of slippery slopes in law and ethics, and we found that some of the best comments and examples on the topic came from Herbert Spencer, who keenly observed the ways in which political choices made in the past can ease the way for related choices in the future. I doubt that my coauthor and I could have duplicated all of Spencer’s insights without reading him.

Third, analysts are often guided in their thinking by the methods most popular among their peers. For at least the last 40 years, the economics profession has been dominated by mathematical modeling. Now, I wouldn’t claim (as do some people I know) that mathematical modeling is undesirable -- it is quite appropriate for many tasks, the most important of which is aiding logical consistency and, as an added benefit, keeping the post-modernists at bay. The problem is that, as the old saying goes, when all you have is a hammer, everything looks like a nail. Economists are drawn to those topics that are most tractable in mathematical terms, which sometimes leads them to ignore topics (such as radical uncertainty, radical ignorance, and systemic complexity) that mathematical models cannot (at present) explore fully without oversimplification. The old philosophers, being neither gifted nor burdened with the high-powered mathematical tools we have today, had no qualms about attacking issues with pure logic and reason. They also had little respect for the artificial lines between disciplines, and ranged freely over a variety of areas, drawing connections that might never be drawn by modern thinkers trapped in their pigeonholes. As a result, their work can be a treasure trove for modern analysts trying to break new ground and cross disciplinary borders.