characterized by or subject to whim; impulsive and unpredictable

Yet another word from The Double—as far as I can tell, used oxymoronically with “pig-headedness”:

…quite without affectation and making no pretense at appearing to be more than what it is, the home of a secondary school teacher who doesn’t earn very much, a fact that may be capricious pig-headedness on the part of the teaching profession or the result of a historical penalty as yet still unpaid.