accidentalism
/ˌaksɪˈdɛntlɪz(ə)m/noun
1The quality of being accidental; accidental manner or nature.
2A theory or belief which proposes that events occur as a result of chance or contingency, and are not preordained or attributable to a single definite cause.
Origin
Mid 19th century; earliest use found in John Ruskin (1819–1900), art critic and social critic. From accidental + -ism.