What's the noun for gradualness? Here's the word you're looking for.
gradualism
(biology) The belief that evolution proceeds at a steady pace, without the sudden development of new species or biological features from one generation to the next.
(transferred sense) The belief that some phenomenon occurs gradually over a long period of time.
(politics) The belief that change ought to be brought about in small, discrete increments rather than in abrupt strokes such as revolutions or uprisings.
“The Hungarian cardinal Péter Erdő, the synod's relator general, came out against the concept of graduality on the Synod's first day.”
“Which kind of method to bring about reforms: drastic therapy or graduality?”
“In a logic of coordination for communion, every team matures the common options and carries out the shared itineraries, giving particular attention to the criteria of continuity and graduality.”