## Birthday Puzzle

Albert and Bernard just met Cheryl. “When’s your birthday?” Albert asked Cheryl. Cheryl thought a second and said, “I’m not going to tell you, but I’ll give you some clues.” She wrote down a list of 10 dates: May 15, May 16, May 19 June 17, June 18 July 14, July 16 August 14, August […]

## List of common fallacies

In daily conversations, we come across many logical fallacies. Discussions and debates often lead nowhere, because the underlying logic is already wrong. Looking for better explanations or more evidence is a good approach, and another one is attacking the problems in your opponents position. The following list briefly describes some of the most common fallacies: You don’t need to […]

## Kurt Gödel

Here is the biographical sketch of Kurt Gödel’s life from the Stanford Encyclopedia of Philosophy: Biographical Sketch Kurt Gödel was born on April 28, 1906 in what was then the Austro-Hungarian city of Brünn, and what is now Brno in the Czech Republic. Gödel’s father Rudolf August was a businessman, and his mother Marianne was a […]

## Incompleteness Theorem

The Incompleteness Theorem is Gödel’s main contribution to 20th century thought. Gödel showed that within a logical system such as Russell and Whitehead had developed for arithmetic, propositions can be formulated that are undecidable or undemonstrable within the axioms of the system. That is, within the system, there exist certain clear-cut statements that can neither be proved or […]

## A History of Set Theory

A set is a collection of things. A set can consist of numbers or letters (such as 1, 2, 3, 4 or a, b, c, d) or of objects (such as chairs or books). Set theory is the field of mathematics that deals with the properties of sets that are independent of the things that […]