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Logic

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,...

/ April 25, 2015

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....

/ November 9, 2014

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...

/ November 21, 2011

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...

/ November 21, 2011

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...

/ November 21, 2011

Kalām Cosmological Argument

From: W. L. Craig: “Professor Mackie and the Kalām Cosmological Argument,” in: Religious Studies, No. 20 (1985), p. 367. “The kalām cosmological argument, as opposed to the Thomistic and Leibnizian, is one of the better-respected arguments for the existence of...

/ November 18, 2011

The Unexpected Hanging Paradox

From the Wikipedia: “A judge tells a condemned prisoner that he will be hanged at noon on one day in the following week but that the execution will be a surprise to the prisoner. He will not know the day...

/ November 17, 2011

Laws of Form

, Chapter 12 Notes. “It seems hard to find an acceptable answer to the question of how or why the world conceives a desire, and discovers an ability, to see itself, and appears to suffer the process. That it does...

/ November 8, 2011