The arithmetization of analysis was a research program in the foundations of mathematics carried out in the second half of the 19th century. Its main proponent was Weierstrass, who argued the geometric foundations of calculus were not solid enough for rigorous work.

The highlights of this research program are:

• the algebraic construction of the real numbers by Dedekind, resulting in the modern axiomatic definition of the real number field;
• the epsilon-delta definition of limit; and
• the naïve set-theoretic definition of function.

An important spinoff of the arithmetization of analysis is set theory. Naive set theory was created by Cantor and others after arithmetization was completed as a way to study the singularities of functions appearing in calculus.

The arithmetization of analysis had several important consequences:

• the banishment of infinitesimals from mathematics until the creation of non-standard analysis by Abraham Robinson in the 1960s;
• the shift of the emphasis from geometric to algebraic reasoning: this has had important consequences in the way mathematics is taught today;
• it made the development of modern measure theory by Lebesgue and the rudiments of functional analysis by Hilbert possible;
• it motivated the more extreme philosophical position that all of mathematics should be derivable from logic and set theory, ultimately leading to Hilbert's program, Gödel's theorems and non-standard analysis.

Quotations:

• "God created the natural numbers, all else is the work of man." -- Kronecker