Word Study
tychism
CIDE DICTIONARY
tychism, n. [Gr. ty`chh fortune, chance + -ism.].
Any theory which conceives chance as an objective reality; esp., a theory of evolution which considers that variation may be purely fortuitous. [Webster 1913 Suppl.]
OXFORD DICTIONARY
tychism, n. Philos. the theory that chance controls the universe.
Etymology
Gk tukhe chance
For further exploring for "tychism" in Webster Dictionary Online