Featured image of post Richard's Paradox: The Contradiction Caused by Infinite Decimals and the "Diagonal Argument"

Richard's Paradox: The Contradiction Caused by Infinite Decimals and the "Diagonal Argument"

Listing all real numbers that can be defined in words, only to create a new real number different from all of them. We provide an easy-to-understand explanation of "Richard's Paradox", which shook the foundations of mathematics, and Gödel's brilliant inspiration that broke through it.

Featured image of post Berry Paradox: The Contradiction That Occurs When Trying to Define a "Number" Using "Words"

Berry Paradox: The Contradiction That Occurs When Trying to Define a "Number" Using "Words"

The very phrase "the smallest integer not expressible in 19 characters or less" ends up expressing that number in under 19 characters!? An explanation of a short, beautiful paradox that occurs at the boundary of everyday language and mathematics.

Featured image of post The Unexpected Hanging Paradox: The Day a Logically "Absolutely Impossible" Test Takes Place

The Unexpected Hanging Paradox: The Day a Logically "Absolutely Impossible" Test Takes Place

"Next week, on one of the days from Monday to Friday, I will give you a surprise test in an unpredictable manner." —— In response to the teacher's declaration, the students proved that "a surprise test is logically impossible." However...

Featured image of post Sleeping Beauty Paradox: Is the coin probability 1/2 or 1/3? A difficult problem dividing probability theory

Sleeping Beauty Paradox: Is the coin probability 1/2 or 1/3? A difficult problem dividing probability theory

"Now that you are awake, what is the probability that the coin toss resulted in heads?" We explain the latest paradox that continues to divide mathematicians and philosophers worldwide into the "1/2 camp" and the "1/3 camp" despite its very simple setup.

Featured image of post Newcomb's Paradox: Can You Beat a Superbeing Who Foresees the Future?

Newcomb's Paradox: Can You Beat a Superbeing Who Foresees the Future?

A transparent box with 100,000 yen and an opaque box with either 100 million yen or nothing. Which would you choose in a game prepared by a superbeing who perfectly predicts the future? We explain the greatest puzzle in modern philosophy where free will and determinism clash.

Featured image of post Simpson's Paradox: The Mysterious Phenomenon of Winning in the Parts but Losing in the Whole

Simpson's Paradox: The Mysterious Phenomenon of Winning in the Parts but Losing in the Whole

Even though the "pass rate" is higher in every department, when the company's overall "total pass rate" is calculated, it reverses and loses!? We explain the terrifying trap of "Simpson's Paradox" where statistical data deceives us in an easy-to-understand way.

Featured image of post Hilbert's Grand Hotel: How to Accommodate Infinite New Guests in a Fully Booked Hotel

Hilbert's Grand Hotel: How to Accommodate Infinite New Guests in a Fully Booked Hotel

The "Grand Hotel" with infinite rooms never turns away a new guest, even when it is completely full. We explain the astonishing logical trick (properties of infinite sets) that allows it to accommodate 1 person, a million people, or even an "infinite number" of guests arriving on a bus.

Featured image of post St. Petersburg Paradox: How Much Would You Pay for a Gamble with "Infinite" Expected Value?

St. Petersburg Paradox: How Much Would You Pay for a Gamble with "Infinite" Expected Value?

A gamble that is mathematically supposed to make you "infinite money". Yet, in reality, nobody would pay a large sum for it. We explain the historical paradox that highlighted the gap between probability theory and human psychology (utility), laying the foundation of modern economics.

Featured image of post Russell's Paradox: Does the "set of all sets that do not contain themselves" contain itself?

Russell's Paradox: Does the "set of all sets that do not contain themselves" contain itself?

“Does the barber who shaves all those in the town who do not shave themselves, shave himself?” This article explains Bertrand Russell's terrifying paradox that shook the foundations of mathematics, “set theory”, and changed the history of logic.

Featured image of post The Prisoner's Dilemma: Why Do We Make Choices Where "Everyone Loses"?

The Prisoner's Dilemma: Why Do We Make Choices Where "Everyone Loses"?

Even when we know that "cooperating with each other yields the best result", why do humans end up betraying each other? Through "The Prisoner's Dilemma", the most famous model in game theory, we will explain mathematically and psychologically the mechanism by which individual rationality creates collective irrationality.

Featured image of post Banach-Tarski Paradox: Cut one sphere and get two spheres of the same size?

Banach-Tarski Paradox: Cut one sphere and get two spheres of the same size?

Did you know that if you cut a single pea and reassemble it like a puzzle, it can become as large as the sun? We explain the bizarre world of the "Banach-Tarski Paradox", the most counterintuitive yet logically perfectly correct theorem caused by the "Axiom of Choice" in modern mathematics.

Featured image of post Achilles and the Tortoise: Can He Catch Up or Not? The Paradox of "Infinity" from Ancient Greece

Achilles and the Tortoise: Can He Catch Up or Not? The Paradox of "Infinity" from Ancient Greece

Can the swift hero Achilles never catch up to the slow-footed tortoise? The most famous of Zeno's paradoxes has troubled philosophers and mathematicians for over 2,000 years. We will mathematically unravel the trick of this logic using the concepts of the sum of infinite series and limits.

Featured image of post Monty Hall Problem: The Trap of Probability Theory that Betrays Intuition and its Complete Resolution using Bayesian Inference

Monty Hall Problem: The Trap of Probability Theory that Betrays Intuition and its Complete Resolution using Bayesian Inference

A TV show game where you choose a winning prize from 3 doors. Should you change your choice after the host opens a losing door? We thoroughly explain the "Monty Hall Problem", which caused a huge controversy involving mathematicians worldwide, from the perspectives of probability theory, Bayesian inference, and cognitive psychology.

Featured image of post The Birthday Paradox: Over 50% with just 23 people? The magic of "combinations" that deceives intuition

The Birthday Paradox: Over 50% with just 23 people? The magic of "combinations" that deceives intuition

Whether it is a school class or a company department, when just 23 people gather, the probability of two people sharing the same birthday exceeds 50%. We explain visually and mathematically using probability theory and graphs how easily human intuition overlooks this "combinatorial explosion".

Featured image of post The Missing Dollar Riddle: Learning Logical Thinking and Accounting Basics from an Intuition-Deceiving Math Paradox

The Missing Dollar Riddle: Learning Logical Thinking and Accounting Basics from an Intuition-Deceiving Math Paradox

Three guests pay $30, later $5 is returned, but the waiter pockets $2 and only returns $3. The guests pay $9 each, totaling $27. Adding the waiter's $2 makes $29. Where did the remaining $1 go? A complete explanation from the perspectives of mathematics, psychology, and accounting.

Featured image of post Principles and Mechanisms of Quantum Computers [Complete Guide]: From the Limits of Moore's Law to Quantum Mechanics

Principles and Mechanisms of Quantum Computers [Complete Guide]: From the Limits of Moore's Law to Quantum Mechanics

Provides a thorough explanation of the background leading to the dawn of quantum computers, from the physical limits of classical computers and the end of Moore's Law to the barriers of quantum mechanical effects like quantum tunneling. This is Chapter 1 of the complete guide to understanding next-generation information processing technologies.