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Various IQ tests have shown the connection between recognising valid inferences (arguments) and the level of ones intelligence; our aim here is to observe what people consider as "valid inference"

A valid argument is said to be impossible for its premise(s) to be true and its conclusion false; a valid argument is free of counterexamples.

For example two valid inferences (arguments):
⁃ Messi is 6 feet tall therefore (=>) Messi is 6 feet tall
⁃ Messi is an Argentinian therefore (=>) Messi is an Argentinian

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This questionnaire is in 3 stages:

• Initial stage: 8 questions with pairs of inferences; our aim here is to acquaint you with the kind of arguments we are interested in; you can run through these questions if you like
• Training stage:
• Final stage: same kind of questions as Initial stage; please answer calmly.

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IQ1. Which inference looks valid to you?

Obama tweeted yesterday ⇒ Obama tweeted yesterday

vs

Messi travelled to Argentina ⇒ Messi travelled to Argentina

i.e

A ⇒ A

vs

A ⇒ A

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IQ2. Which inference looks valid to you?

Aristotle is smiling ⇒ Aristotle is smiling

vs

Albert Einstein had dinner ⇒ Joe Biden is in France

i.e

A ⇒ A

vs

A ⇒ B

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IQ3. Which inference looks valid to you?

The clock is brown or the grass is green => the clock is brown

vs

It will rain tomorrow or It will not rain tomorrow => It will rain tomorrow

i.e

A ∨ B ⇒ A

vs

A ∨ ¬A ⇒ A

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IQ4. Which inference looks valid to you?

She is a friend and She is not a friend => 5 + 5 = 11

vs

2+2=4 => It is snowing or It is not snowing

i.e

A ⋀ ¬A ⇒ ⏊

vs

⏉ ⇒ A ∨ ¬A

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IQ5. Which inference looks valid to you?

The correct spelling for “colour” is with a ‘u’ and The correct spelling for “colour” is without a ‘u’ => 5+5=11

vs

Galicia is in Spain and Galicia is in Spain => Galicia is in Spain

i.e

A ⋀ ¬A ⇒ ⏊

vs

A ⋀ A ⇒ A

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IQ6. Which inference looks valid to you?

2+2=4 => I know your name or I do not know your name

vs

The boy is my brother or The boy is my brother => The boy is my brother

i.e

⏉⇒ A ∨ ¬A

vs

A ∨ A ⇒ A

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IQ7. Which inference looks valid to you?

The chair is green or The chair is not green => The chair is green

vs

Aristotle is a philosopher and Aristotle is not a philosopher => 5+5=11

i.e

A ∨ ¬A ⇒ A

vs

A ⋀ ¬A ⇒ ⏊

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IQ8. Which inference looks valid to you?

Aristotle is a philosopher or Messi is a footballer => Aristotle is a philosopher

vs

2+2=4 => she is a friend or she is not a friend

i.e

A ∨ B ⇒ A

vs

⏉ ⇒ A ∨ ¬A

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