Is there a better noun form of "unreasonable" than "unreasonableness?"

I simply can't bring myself to use unreasonableness, but can think of no synonym or alternate form with comparable meaning.

I'll restructure if necessary, but wonder if I'm missing a suitable alternative.

You could try contrariness, obduracy, or obstinacy.

Here are a few alternatives to "unreasonableness"

• inflexibility
• immovability
• intransigence
• intractability
• stubbornness
• recalcitrance
• willfulness
• contrariness
• doggedness
• single-mindedness

How about irrationality, or pigheadedness for that vernacular charm? Incorrigibility could also fit, as could idiocy, although I think those are deviating from "unreasonableness." Megalomania most likely doesn't work, but it's a wonderful word. :)