In the Middle Ages, the call for a crusade to conquer the Holy Land was met with cries of “Deus vult!” — God wills it. But did the crusaders really know what God wanted? Given how the venture turned out, apparently not.

Now, that was a long time ago, and, in the areas I write about, invocations of God’s presumed will are rare. You do, however, see a lot of policy crusades, and these are often justified with implicit cries of “Mercatus vult!” — the market wills it. But do those invoking the will of the market really know what markets want? Again, apparently not.

And the financial turmoil of the past few days has widened the gap between what we’re told must be done to appease the market and what markets actually seem to be asking for.

To get more specific: We have been told repeatedly that governments must cease and desist from their efforts to mitigate economic pain, lest their excessive compassion be punished by the financial gods, but the markets themselves have never seemed to agree that these human sacrifices are actually necessary. Investors were supposed to be terrified by budget deficits, fearing that we were about to turn into Greece — Greece I tell you — but year after year, interest rates stayed low. The Fed’s efforts to boost the economy were supposed to backfire as markets reacted to the prospect of runaway inflation, but market measures of expected inflation similarly stayed low.