Synonyms for Capriciousness (same or very similar meaning)
WordNet sense 1 (the quality of being guided by sudden unpredictable impulses):
unpredictabilityWordNet sense 2 (the trait of acting unpredictably and more from whim or caprice than from reason or judgment):
arbitrariness, flightiness, whimsey, whimsicality, whimsyFrom the ODE community, based on WordNetadd/edit