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:
Although modern constructivists don't take such a strong view, they can trace the origins of constructivism back to Kronecker's work.