aleatory
/ˈeɪliəˌtɔri/
adjective
Depending on the throw of a dice or on chance; random.
Fortunately, some cosmologists have lately begun to consider models in which the ‘initial conditions’ are aleatoric and hence far from simple.
fortuitous,chance,occurring by accident,occurring by chance,adventitious,fluky,coincidental,casual,serendipitous,random,aleatory