Irreligion: A Mathematician Explains Why the Arguments for God Just Don't Add Up

Irreligion: A Mathematician Explains Why the Arguments for God Just Don't Add Up is a book by John Allen Paulos published in 2008. As the subtitle indicates, Paulos presents various arguments that have been proferred as evidence for God and briefly explains why they are lacking. Along the way, he occasionally digresses onto different topics.

Four Classical Arguments

 * Argument from first cause
 * The Argument from design (and Some Creationist Calculations)
 * A Personally Crafted Pseudoscience
 * The Argument from the Anthropic principle (and a Probabilistic Doomsday)
 * The Ontological argument (and Logical Abracadabra)
 * Self-Reference, Recursion, and Creation

In the A Personally Crafted Pseudoscience chapter, Paulos shows how easy it is to come up with numerical coincidences that appear meaningful. For instance, the ratio between your hair length and shoe size might be the same as the ratio of the heights of the tallest and second-tallest building in the United States.

Four Subjective Arguments

 * The Argument from coincidence (and 9/11 Oddities)
 * The Argument from Prophecy (and the Bible Codes)
 * An Anecdote on Emotional Need
 * The Argument from Subjectivity (and Faith, Emptiness, and Self)
 * The Argument from Interventions (and Miracles, Prayers, and Witnesses)
 * Remarks on Jesus and Other Figures

The argument from interventions is, briefly, that some event is claimed to be a miracle or other divine intervention, which implies that God caused it, and therefore God exists.

Four Psycho-Mathematical Arguments

 * The Argument from Redefinition (and Incomprehensible Complexity)
 * The Argument from Cognitive Tendency (and Some Simple Programs)
 * My Dreamy Instant Message Exchange with God
 * The Universality Argument (and the Relevance of Morality and Arguments)
 * The Gambling Argument (and Emotions from Prudence to Fear)
 * Atheists, Agnostics, and "Brights"

The argument from cognitive tendency is, briefly, that since most humans, regardless of culture, historical era, etc., believe in God, that such belief is a universal natural phenomenon. Therefore, this belief is warranted, and God exists.

In the same chapter, Paulos talks about the notion that "like causes like": good people do good deeds, diseased trees produce diseased fruit, and so forth. If like does indeed cause like, then complex systems like living beings require a complex cause. This leads naturally to the watchmaker argument.

The universality argument starts by noting that people across a wide range of cultures have roughly similar moral codes, and that the most plausible source for this universal morality is God. (See also Moral argument.)