ToK Rationalism: ToK Rationalism: the use of reasonthe use of reason

Rational & EmotionalRational & EmotionalRational & EmotionalRational & Emotional

If you want to annoy someone, explain to them, logically and rationally, why they are wrong.

J Baylock

If you want to annoy someone, explain to them, logically and rationally, why they are wrong.

J Baylock

ToK Rationalism: introductionToK Rationalism: introduction

ToK Rationalism: the use of ToK Rationalism: the use of reasonreason

Rational & EmotionalRational & EmotionalRational & EmotionalRational & Emotional

What has reason told us about prehistoric man?What has reason told us about prehistoric man?

How might our emotions inform us about prehistoric man?

How might our emotions inform us about prehistoric man?

ToK Rationalism: the use of ToK Rationalism: the use of reasonreason

ReasoningReasoningReasoningReasoning

• Reasoning and deduction….• Reasoning and deduction….Example:

A: All humans are mortal

B: I am human

C: (deduction)I am mortal

Example:

A: All humans are mortal

B: I am human

C: (deduction)I am mortal

Example:

A: I am either a schnooglepopper or a birshteinwaller, or both

B: I am not a schnooglepopper

C: I am a birshteinwaller

Example:

A: I am either a schnooglepopper or a birshteinwaller, or both

B: I am not a schnooglepopper

C: I am a birshteinwaller

ToK Rationalism: the use of ToK Rationalism: the use of reasonreason

In groups of 3 or 4, In groups of 3 or 4, please please

A.A.Make up 2 other Make up 2 other absolutely convincing absolutely convincing examplesexamples

B.B. Make up 2 Make up 2 arguments which arguments which seem convincing, but seem convincing, but in fact, are notin fact, are not

In groups of 3 or 4, In groups of 3 or 4, please please

A.A.Make up 2 other Make up 2 other absolutely convincing absolutely convincing examplesexamples

B.B. Make up 2 Make up 2 arguments which arguments which seem convincing, but seem convincing, but in fact, are notin fact, are not

ToK Rationalism: the use of ToK Rationalism: the use of reasonreason

•Reasoning and induction…•Reasoning and induction…All adult swans are whiteAll adult swans are white

ToK Rationalism: the use of ToK Rationalism: the use of reasonreason

•Reasoning and induction…•Reasoning and induction…

It’s induction because…

The speaker has drawn a general conclusion from many specific sightings – maybe thousands(remember induction in science?)

It’s induction because…

The speaker has drawn a general conclusion from many specific sightings – maybe thousands(remember induction in science?)

ToK Rationalism: the use of ToK Rationalism: the use of reasonreason

•Reasoning and induction…•Reasoning and induction…

The problem with The problem with induction?induction?

The problem with The problem with induction?induction?

The way it has been, may not be the way it always will be…..

The way it has been, may not be the way it always will be…..For example, there is a species of black swan

For example, there is a species of black swan

Australian Black Swan chicks

ToK Rationalism: the use of ToK Rationalism: the use of reasonreason

Reasoning and deductiondeduction again.. Reasoning and deductiondeduction again..

Example:

A: No emperors are dentists

B: All children fear dentists

C: No children fear emperors

Example:

A: No emperors are dentists

B: All children fear dentists

C: No children fear emperors

ToK Rationalism: the use of ToK Rationalism: the use of reasonreason

Reasoning and deductiondeduction again.. Reasoning and deductiondeduction again..

Example:

A: No monkeys are soldiers

B: All monkeys are smelly

C: Some smelly creatures aren’t soldiers

Example:

A: No monkeys are soldiers

B: All monkeys are smelly

C: Some smelly creatures aren’t soldiers

Soldiers

Smelly creatures

Monkeys

Soldiers

Smelly creatures

Monkeys

Venn diagramVenn diagram

Once you understand Once you understand the logic, try drawing the logic, try drawing

your own for the your own for the examples on page 78 in examples on page 78 in

books..books..

Once you understand Once you understand the logic, try drawing the logic, try drawing

your own for the your own for the examples on page 78 in examples on page 78 in

books..books..

ToK Rationalism: the use of ToK Rationalism: the use of reasonreason

DeductionDeduction truth and validity… DeductionDeduction truth and validity…Example:

A: All students are lazy

B: I am a student

C: I am lazy

Example:

A: All students are lazy

B: I am a student

C: I am lazyTruth of premises

Validity of logic

True False

Valid Conclusion must be T

Conclusion must be T or F

Invalid Conclusion must be T or F

Conclusion must be T or F

ToK Rationalism: the use of ToK Rationalism: the use of reasonreason

Once you understand Once you understand the logic, do the the logic, do the exercises on p79exercises on p79

Once you understand Once you understand the logic, do the the logic, do the exercises on p79exercises on p79