Celebrating René Descartes, the first modern philosopher, and his famous phrase Ego cogito, ergo sum, we call our model for human knowledge the Sum. Our model for an objective value, independent of humanity, we call Ergo. Our two-stage model for free will we call the Cogito. And our model for the mind we call the Ego. The Sum of all the information created by human beings is a miniscule fraction of the Ergo (negative entropy or information) in the universe. But it is the sum of all human knowledge, and in human intellectual terms we can regard it as the highest and most valuable form of information. Knowledge is information stored in human minds and in human artifacts like stories, books, and internetworked computers. Knowledge is information that forms the basis for human thoughts and actions. Among these are theories and experiments of scientists, who collaborate to establish our knowledge of the external world.
Information is stored or encoded in structures. Structures in the world build themselves, following natural laws, including physical and biological laws. Structures in the mind are partly built by biological processes and partly built by human intelligence, which is free, creative, and unpredictable. To the extent of the correspondence, the isomorphism, the one-to-one mapping, between structures (and processes) in the world and representative structures in the mind, we can claim to have knowledge of the world. The Sum is all of that knowledge, in all human minds and their works.