Hume's Principle or HP—the terms were coined by George Boolos—says that the number of Fs is equal to the number of Gs if and only if there is a one-to-one correspondence (a bijection) between the Fs and the Gs. HP can be stated formally in systems of second-order logic. Hume's Principle is named for the Scottish philosopher David Hume.
HP plays a central role in Gottlob Frege's philosophy of mathematics. Frege shows that HP and suitable definitions of arithmetical notions entail all axioms of what we now call second-order arithmetic. This result is known as Frege's theorem, which is the foundation for a philosophy of mathematics known as neo-logicism.
Read more about Hume's Principle: Origins, Influence On Set Theory
Famous quotes containing the words hume and/or principle:
“That three times five is equal to the half of thirty, expresses a relation between these numbers. Propositions of this kind are discoverable by the mere operation of thought, without dependence on what is any where existent in the universe. Though there never were a circle or triangle in nature, the truths, demonstrated by Euclid, would for ever retain their certainty and evidence.”
—David Hume (1711–1776)
“The sons of Judah have to choose that God may again choose them.... The divine principle of our race is action, choice, resolved memory.”
—George Eliot [Mary Ann (or Marian)