hand: two apples, two oranges and two brass number plates. These are all sets of two things and ‘two’ is the collection of all these sets. In 1890, Gottlob Frege completed his theory of sets. The project had taken him five years. Unfortunately, just before sending the book to the publisher, Bertrand Russell wr

--- mathematics, for example: Whitehead and Russell’s Principia Mathematica in 1910 was the biggest showoff effort. There were previous attempts by Gottlob Frege and Giuseppe Peano that were a little more modest in their presentation. Ultimately, they were wrong in what they thought they should formalize: They

--- mathematics, for example: Whitehead and Russell’s Principia Mathematica in 1910 was the biggest showoff effort. There were previous attempts by Gottlob Frege and Giuseppe Peano that were a little more modest in their presentation. Ultimately, they were wrong in what they thought they should formalize: They