What do the ¯elds of astronomy, economics, ¯nance, law, mathematics, med-
icine, physics, and sociology have in common? Not much in the way of sub-
ject matter, that's for sure. And not all that much in the way of methodology.
What they do have in common, with each other and with many other ¯elds, is
their dependence on a certain standard of rationality.