Questions you dare not ask (updated)

There are some questions even Tyler Cowen hesitates to ask, like this one,

The question is, when inflation comes, why doesn't the expectation of that inflation lead to proportional increases in nominal interest rates, thus keeping the real rate constant? The studies I've seen all indicate a less than one-to-one Fisher effect.

Tyler offers six possible explanations here.

Update: Arnold Kling puts his two cents worth in.