Paradoxes That Make You Think Trivia Quiz

Answer: Why have we never detected signs of intelligent life elsewhere?

Physicist Enrico Fermi posed the famous question during a lunch conversation at Los Alamos National Laboratory in 1950. Despite the vast number of stars and planets in the universe and the possibility that intelligent civilisations exist elsewhere, we have never detected confirmed evidence of intelligent extraterrestrial life. This apparent contradiction is the central question of the Fermi Paradox: if intelligent life should be possible elsewhere, why haven't we found any signs of it?

Various solutions have been proposed, including the possibility that intelligent civilisations destroy themselves before becoming advanced enough to communicate, or that the vast distances involved make contact effectively impossible. Other ideas suggest that intelligent life may simply be far rarer than expected.

I keep an open mind about the existence of aliens. As there have been numerous reports of UFO sightings and reports of people having contact with various types of aliens, I'm inclined to believe that it's possible that they exist. I would need irrefutable proof, however, before I accepted it as fact.

Answer: Simultaneously alive and dead

I think a lot of you might be familiar with Schrodinger's Cat. It's a thought experiment which was devised by physicist Erwin Schrodinger in 1935. In the experiment, a cat inside a sealed box is linked to a random subatomic event. If a single atom decays, a mechanism releases poison and the cat dies.

Until the box is opened and observed, quantum mechanics suggests the cat exists in a superposition of both alive and dead states simultaneously. Schrodinger intended the thought experiment as a critique of applying quantum theory to everyday objects.

Incidentally, the breed of cat doesn't matter. :)

Answer: Is it still the same ship?

According to legend, the Athenians preserved the ship that Theseus used to return from Crete by replacing its planks as they rotted, one by one, until none of the original timber remained. It has since become one of philosophy's best-known thought experiments about identity and change.

The paradox asks whether the ship is still the same ship once every original plank has been replaced. It has since been applied to questions of personal identity. If every cell in a human body is replaced over time, are you still the same person? Good question. I'm now wondering if I'm a different person! :D

Answer: If it is true it is false and if it is false it is true

The Liar's Paradox is one of the oldest paradoxes in logic. It can be traced back to ancient Greek philosophers. The simplest form is the statement, 'This sentence is false.' If the statement is true, then it must be false. If it is false, then it must be true. The loop has no resolution.

This paradox influenced the development of modern mathematical logic, including the work of Bertrand Russell. Its self-referential structure resembles ideas used later in Kurt Godel's incompleteness theorems. It continues to be studied in philosophy, mathematics and computer science because it highlights the difficulties involved in defining truth and self-reference.

Answer: At least two people share the same birthday

The Birthday Paradox is a famous result in probability theory showing that in a surprisingly small group of people, the likelihood of two sharing the same birthday is much higher than most people expect.

It might surprise you to know that assuming birthdays are evenly distributed throughout the year, a group of just 23 people has a greater than 50% chance that at least two share a birthday. With 57 people, the probability rises to over 99%.

Answer: The length of the measuring tool used

The Coastline Paradox was first identified by mathematician Lewis Fry Richardson in the 1950s. While studying whether the length of shared borders between countries affected the likelihood of war, he noticed that Spain and Portugal had recorded very different lengths for their shared border.

The reason is that the smaller the unit of measurement used, the more detail is captured, including bays, inlets and headlands, and the longer the measured length becomes. In theory there is no single definitive length for a coastline because it depends entirely on the scale of measurement.

Answer: The question has no logical answer

The Barber Paradox is associated with mathematician Bertrand Russell. In a town, the barber shaves every man who does not shave himself, and only those men. The question is: who shaves the barber? If he shaves himself, he breaks the rule that he only shaves men who do not shave themselves. If he does not shave himself, then he must shave himself.

There is no logical answer to the question. Russell used similar reasoning to expose a fundamental flaw in naive set theory.

When I was writing this quiz, I must admit that out of all the paradoxes featured, this one had my brain going round and round in circles for ages! I hope it didn't have the same effect on you. :)

Answer: Each person assumes the others want it and goes along

The Abilene Paradox was described by management expert Jerry B. Harvey in his 1974 article 'The Abilene Paradox: The Management of Agreement.' In the original story, a family in Coleman, Texas, drives 53 miles to Abilene for a meal that nobody actually wants because each person assumes the others want to go and does not speak up.

The paradox describes situations in which a group takes collective action that none of its individual members actually supports because each person misreads what the others want. Today it is widely used in business, politics and organisational management to explain poor group decision-making.

Answer: The traveller could not have been born to make the journey

The Grandfather Paradox is one of the best-known paradoxes associated with time travel. It explores what happens when a journey into the past creates a contradiction that prevents the traveller's own existence. If a time traveller went back and killed their grandfather before their parent was born, the traveller could never have been born and therefore could never have made the journey back in time to kill their grandfather. This creates a logical contradiction: the traveller both must and must not exist.

Various theoretical solutions have been proposed, including parallel timelines and the idea that the universe prevents changes that would create contradictions. The paradox has appeared in countless science-fiction stories, including 'Doctor Who', 'Back to the Future' and 'The Terminator'.

Answer: They feel less satisfied and find it harder to decide

The Paradox of Choice was popularised by American psychologist Barry Schwartz in his 2004 book of the same name. He argued that having more choices does not make people happier. Instead, it makes decisions harder, increases anxiety and often leads to lower satisfaction with the chosen option because people compare it with all the alternatives they did not choose.

His work challenged the assumption that more freedom of choice always leads to greater wellbeing. The idea has influenced research into consumer behaviour, economics and psychology, and is often used to explain why choosing from hundreds of products or streaming titles can feel surprisingly difficult.