When newer isn't better

William Broadway, a student at Loughborough University, has invented a way of keeping vaccines cool which might save over a million lives by reviving an invention of Albert Einstein���s. This reminds us of an important fact ��� that intellectual progress isn���t necessarily linear. Instead, good ideas can be forgotten and bad ones developed, so that science can regress.

For example, the Romans knew how to remove cataracts, knowledge which wasn���t rediscovered until the 20th century; the steam engine was invented in the first century AD, but long forgotten; and the standard of battlefield medicine might well have been higher in the British civil wars than it was at Crimea two centuries later. The renaissance was so-called because forgotten knowledge was rediscovered.

What���s more, a lot of what looks like progress ain���t so. The replications crises in psychology, economics and medicine (if such there be) warn us that new findings aren���t wholly reliable.

I don���t say this to come over all John Gray on you and deny the existence of progress. Instead, I do so to challenge an implicit presumption many of us have  - that today���s work is superior to that of 10, 20 or even 100 years ago.

Instead, it���s possible that peer review and grant-awarding processes sometimes select for fashionable rather than effective research; that informational overload means that some good ideas get neglected; and/or that increasingly narrow fields of specialism cause inspiring ideas from separate fields to be ignored.

It���s from this perspective that we should view the debate about the relative merits of stock-flow consistent or heterodox models against DSGE ones. I don���t want to take a view on Brad DeLong���s claim that DSGE models have been ���a catastrophic failure���, but I can say that if they are there���s nothing unique about fashionable research programmes being a dead-end or in once-forgotten ideas proving powerful when they are revived.

To take but two examples of the latter, I���d suggest that the macroeconomics of income distribution are better analysed through Marxian-Kaleckian (pdf) models in which power matters rather than through more ���modern��� theories, and that the theory of natural selection ��� which Darwin took from economics ��� contains many insights that enrich our understanding of economics.

My point here should be a trivial one. We should not presume that newer means better, because institutions don���t always select ideas optimally. One reason why we should study the history of ideas is that doing so reminds us of this fact.