Freya’s favourite teacher was Mrs Poole: Freya always remembers the interesting lesson when Mrs Poole told them “H 2 O is water” and it started her interest in chemistry. Mr Leake, however, was an awful teacher: Freya will never forget when he said “Water is water” – as if that was useful knowledge! Are Mrs Poole and Mr Leake saying anything different from each other?

Today we will learn what is meant by: Actually possible Logically possible Logically impossible Necessary truth Contingent truth Analytic truth Synthetic truth A priori A posteriori

Actually possible: it could genuinely happen with the laws of physics as we know them Logically possible: you can conceive of it (it may or may not be actually possible) Logically impossible: you can’t conceive of it; it’s a contradiction

Actually possible Logically (but not actually) possible Logically impossible A cow runs across a field A cow jumps over the moon A cow is not a cow

Actually possibleLogically (but not actually) possible Logically impossible

A 3 sided triangle Karen can change into a lion by clicking her fingers Karen eats her own leg Karen eating 4 bags of crisps in one sitting Fish swimming on the surface of the sun Karen marries a goblin Karen travels through time to meet Socrates Karen eats 4 aeroplanes in one sitting A cube which is 1- dimensional Karen exists and doesn’t exist at the same time = 4 Two parallel lines crossing over = 5A 4 sided triangle Karen wins the lottery this week

Actually possibleLogically (but not actually) possible Logically impossible A 3 sided triangleKaren can change into a lion by clicking her fingers Karen exists and doesn’t exist at the same time Karen eating 4 bags of crisps in one sitting Fish swimming on the surface of the sun A 4 sided triangle = 4Karen eats 4 aeroplanes in one sitting = 5 Karen eats her own leg Karen travels through time to meet Socrates Two parallel lines crossing over Karen wins the lottery this week Karen marries a goblinA cube which is 1- dimensional

Analytic truths are true as a result of their meaning. If you know the meanings (definitions) of the words, you know it is true Synthetic truths are true, but you need to understand the meanings of the words AND something about the world

AnalyticSynthetic TrueVixens are female foxes (analytically true) Vixens might bite people when cornered (synthetically true) FalseVixens are male pigs (analytically false) Vixens are capable of ballroom dancing (synthetically false) The definition of a vixen is that it’s a female fox

AnalyticSynthetic True(analytically true)(synthetically true) False(analytically false)(synthetically false)

Dogs are descended from wolves Prince William is a bachelor Karen owns a dog Most dogs are able to speak Polish Triangles have three sidesTriangles have 5 sides Bachelors are unmarried men We are in the canteenWe are in room C is a number Dogs are not descended from wolves Justin Bieber is a bachelor Bachelors are baby girls7 is a colour There are 7 dwarves in Snow White

AnalyticSynthetic True (analytically true) Dogs are descended from wolves Triangles have three sides Bachelors are unmarried men 7 is a number (synthetically true) Karen owns a dog We are in room C.1.12 Justin Bieber is a bachelor There are 7 dwarves in Snow White False (analytically false) Dogs are not descended from wolves Triangles have 5 sides Bachelors are married 7 is a colour (synthetically false) Most dogs are able to speak Polish We are in the canteen Prince William is a bachelor There are 7 counties in England Dog = a pet descended from wolves Triangle = 3-sided shape Bachelor = unmarried man 7 = the number between 6 and 8

Can analytic truths tell us anything useful or interesting about the world?

Something is necessarily true if it is true by definition, or it couldn’t have been any other way. Analytic and mathematical truths are usually necessary Something is contingently true if it is true, but it could have been otherwise.

NecessaryContingent True(necessarily true)(contingently true) False(necessarily false)(contingently false)

There are some yellow cubes Prince William has 2 children Karen is the genetic product of her father and her mother There are no yellow cubes AS Philosophy is taught in room C.1.12 at Bilborough = 4 AS Philosophy is taught in the car park at Bilborough Karen is the genetic product of a hippo and a giraffe Karen has blue hair A cube is 3-dimensionalLittle things are enormousLittle things are little Prince William has 4 children Karen has long hair A cube is round = 6

NecessaryContingent True(necessarily true) Little things are little Karen is the genetic product of her father and her mother A cube is 3 dimensional = 4 (contingently true) AS Philosophy is taught in room C.1.12 at Bilborough Karen has long hair There are some yellow cubes Prince William has 2 children False(necessarily false) Little things are enormous Karen is the genetic product of a hippo and a giraffe A cube is round = 6 (contingently false) AS Philosophy is taught in the car park at Bilborough Karen has blue hair There are no yellow cubes Prince William has 4 children

Do necessary truths – such as mathematics – tell us anything useful about the world? Are there any ambiguous examples? Philosophy of religion link: is God a necessary being (does he have to exist)?

A priori knowledge can be known without any experience (pronounced ay-pry-OR-eye) A posteriori knowledge requires experience to know if it’s true (pronounced ay-pos-teer-ee-OR-eye)

Generally speaking… Analytic and necessary truths can be know a priori Synthetic and contingent truths can only be known a posteriori ANALYTIC NECESSARY A PRIORI SYNTHETIC CONTINGENT A POSTERIORI

Fill in this table with ticks Logically possible Actually possible Actually true Necessarily true Contingently true Analytically true Synthetically true This topic is part of AS Philosophy It’s snowing in Bilborough right now The sky is blue = = 5 ‘Chair’ is a noun You can travel back in time I exist I am purple 2006 is a number Complete this table with ticks as appropriate

Fill in this table with ticks Logically possible Actually possible Actually true Necessarily true Contingently true Analytically true Synthetically true This topic is part of AS PhilosophyYYY Y Y It’s snowing in Bilborough right nowYY The sky is blueYYY Y Y = 4YYY Y Y = 5 ‘Chair’ is a nounYYYY Y You can travel back in timeY I existYYY Y? I am purpleY 2006 is a numberYYYY Y

Look on moodle links and do a mind map on Empiricism For Friday 20 November