Megan McArdle is, predictably, trying to rationalize her refusal to learn a darn thing from having been wrong about Iraq.

The universe being a complicated place, you can usually tell multiple stories from the same pieces of evidence. We learn by gambling on what we think the best answer is, and seeing how it turns out. Most of us know that we have learned more about the world, and ourselves, from failing than from success. Success can be accidental; failure is definite. Failure tells us exactly what doesn’t work.

Baloney. Failure can be accidental too, but the Iraq war was no accident. What bothers many people about the decision to initiate that war is not that the conclusion was wrong but that the very process leading up to it was practically designed to guarantee a wrong conclusion. It is, unfortunately, the very same process and mindset still very much in evidence among people like Megan. Not all failures are deliberate, but the deliberate ones provide an opportunity for self-improvement. That can only happen, though, if the people who were deliberately wrong engage in a little introspection, and change those disastrous mental habits. Megan not only fails to engage in such introspection, but actively refuses to do so. Putting on airs because you were wrong is just a little bit silly, but claiming the “virtue of failure” while refusing to do the one thing that might be virtuous in this situation simply piles a moral flaw on top of the intellectual one.