Type Theory

From the discovery of the antinomiesAntinomy of set theorySet theory, Bertrand RussellRussell, Bertrand concluded that a hierarchy of mathematical objects is necessary. As a solution, he invented type theoryType theory. His ideas were incorporated into the book “Principia mathematica” with Alfred North WhiteheadWhitehead, Alfred North. The presentation therein seemed complicated and initially did not catch on.