In the philosophy of mathematics,

**finitism**is an extreme form of constructivism, according to which a mathematical object does not exist unless it can be constructed from natural numbers in a finite number of steps. (Most constructivists, in contrast, allow a countably infinite number of steps.) The most famous proponent of finitism was Leopold Kronecker, who said:

- "God created the integers, all else is the work of man."

Even stronger than finitism is the *ultraintuitionism* (or *ultrafinitism* as it is now more commonly known) of A. S. Esenin-Vol'pin.