I have a particular fondness for instances illustrating the incommensurability of different reactions to political events, examples of how different people, aligned at different points of the political spectrum, see things so differently that debate or discussion is not likely to effect any changes of mind.

Here's Paul Krugman in yesterday's New York Times, complaining about the "political posturing" that has already begun regarding the scope and size of the Obama stimulus package:

The biggest problem facing the Obama plan is likely to be the demand of many politicians for proof that the benefits of the proposed public spending justify its costs — a burden of proof never imposed on proposals for tax cuts.

This is a problem with which Keynes was familiar: giving money away, he pointed out, tends to be met with fewer objections than plans for public investment 'which, because they are not wholly wasteful, tend to be judged on strict 'business principles.'"

Now, what's interesting about this is not just that it's absurd; it's that Krugman (who is, after all, a really smart guy) doesn't see that it's absurd. The difference between public spending and tax cuts is that the former takes peoples' money away from them for an ostensibly public purpose, while the latter returns money to people that they already earned. It's really not that hard to see that the one calls for a higher "burden of justification" than the other, and that that's not a "problem" that needs to be overcome.