Alfred North Whitehead and Bertrand Russell published Principia Mathematica in three volumes from 1910 to 1913. The project attempted to derive all mathematical truths from a set of axioms using symbolic logic. The proof that 1+1=2 doesn't appear until Volume II, around page 362. Russell later said the work took them ten years of grinding labor and nearly broke both of them intellectually.
This is a completely different book from Isaac Newton's Philosophiae Naturalis Principia Mathematica (1687), which laid out the laws of motion and universal gravitation. They share a name and nothing else. Newton's is physics; Whitehead and Russell's is pure logic.
Alfred North Whitehead and Bertrand Russell published Principia Mathematica in three volumes from 1910 to 1913. The project attempted to derive all mathematical truths from a set of axioms using symbolic logic. The proof that 1+1=2 doesn't appear until Volume II, around page 362. Russell later said the work took them ten years of grinding labor and nearly broke both of them intellectually.
This is a completely different book from Isaac Newton's Philosophiae Naturalis Principia Mathematica (1687), which laid out the laws of motion and universal gravitation. They share a name and nothing else. Newton's is physics; Whitehead and Russell's is pure logic.