/lectures /logic

Fantasy Logic League A weekly competition… …in the art of deduction

Previously on THG…

22 November, 1963 Nightmare on Elm Street

Oswald Sentences [A] If Oswald didn’t shoot Kennedy, then somebody else did. [B] If Oswald doesn’t shoot Kennedy, then somebody else will. [C] If Oswald hadn’t shot Kennedy, then somebody else would have.

The scientific study of: English Grammar

Miss Ann Widdecombe

Spinster of this parish…

…and, indeed, of all the other parishes as well

A woman of many parts…

….clumsily assembled

Truly, the face that ate a thousand chips.

Miss Anne Widdecombe at the Conservative Party Conference

A Counterblast English has NO infinitive English has NO moods – neither indicative nor subjunctive nor any other English has but TWO tenses – present and past

Madness! Ignorance! Stupidity! Snobbery!

Ambiguity

We must have the worst JCR food in Oxford

That dart might have landed in baby’s eye

Sentence vs. Message

Truth is not a property of Sentences

Truth is a property of Messages

Message determines Sentence

If Oswald didn’t shoot Kennedy, then somebody else did

April, 1985 A train from Paddington to Bodmin…

The Adventure of….

The curious incident of the dog in the night-time “Is there any point to which you would wish to draw my attention?” “To the curious incident of the dog in the night-time” “The dog did nothing in the night-time.” “That was the curious incident,” remarked Sherlock Holmes.

The Mystery of…. Modus Ponens

P If P, then Q So: Q

Oswald didn’t shoot Kennedy… And if Oswald didn’t shoot Kennedy… …then somebody else did. So: Somebody else did.

April, 1985 Oxford

The Reverend Charles Lutwidge Dodgson

Lewis Carroll

"What the Tortoise Said to Achilles," Mind 4, No. 14 (April 1895):

Zeno of Elea

A Farewell to Arms

Zeno of Elea

Achilles and the Tortoise

[A] Someone shot Kennedy [B] Oswald didn’t So [Z] Somebody else did

[A] Someone shot Kennedy [B] Oswald didn’t [C] If A and B, then Z [D] If A and B and C, then Z [E] If A and B and C and D, then Z [F] If A and ……oh, forget it!

Words/Sentences Ideas/Messages Logic

Words

Although it was very hot, Her Majesty wore a cardiganAlthough Because it was very hot, Her Majesty stripped offBecause Since there are no trees in Orkney, it is a desolate placeSince Unless I have made a mistake, the answer is 42Unless Whether or not you like them, carrots are good for youWhether or not

Despite the fact that Mike Tyson is a convicted rapist, this government let him in Even if Grannie was gunned down this morning, she’s chirpy enough nowEven if If Oswald didn’t shoot Kennedy, somebody else didIf

Compound Sentences Compounded out of prior sentences

AlthoughAlthough it was very hot, Her Majesty wore a cardigan BecauseBecause it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

Although it was very hot, Her Majesty wore a cardigan BecauseBecause it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

Although it was very hot, Her Majesty wore a cardigan Because it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

Although it was very hot, Her Majesty wore a cardigan Because it was very hot, Her Majesty stripped off Since there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

Although it was very hot, Her Majesty wore a cardigan Because it was very hot, Her Majesty stripped off Since there are no trees in Orkney, it is a desolate place Unless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

Although it was very hot, Her Majesty wore a cardigan Because it was very hot, Her Majesty stripped off Since there are no trees in Orkney, it is a desolate place Unless I have made a mistake, the answer is 42 Whether or not you like them, carrots are good for you

The Independent Sentence

AlthoughAlthough it was very hot, Her Majesty wore a cardigan BecauseBecause it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

AlthoughAlthough it was very hot, Her Majesty wore a cardigan BecauseBecause it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

AlthoughAlthough it was very hot, Her Majesty wore a cardigan BecauseBecause it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

AlthoughAlthough it was very hot, Her Majesty wore a cardigan BecauseBecause it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

AlthoughAlthough it was very hot, Her Majesty wore a cardigan BecauseBecause it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

AlthoughAlthough it was very hot, Her Majesty wore a cardigan BecauseBecause it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

The Subsidiary String

AlthoughAlthough it was very hot, Her Majesty wore a cardigan BecauseBecause it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

Although it was very hot, Her Majesty wore a cardigan BecauseBecause it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

Although it was very hot, Her Majesty wore a cardigan Because it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

Although it was very hot, Her Majesty wore a cardigan Because it was very hot, Her Majesty stripped off Since there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

Although it was very hot, Her Majesty wore a cardigan Because it was very hot, Her Majesty stripped off Since there are no trees in Orkney, it is a desolate place Unless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

Although it was very hot, Her Majesty wore a cardigan Because it was very hot, Her Majesty stripped off Since there are no trees in Orkney, it is a desolate place Unless I have made a mistake, the answer is 42 Whether or not you like them, carrots are good for you

A Subordinating Conjunction prefixed to The Dependent Sentence

Although it was very hot, Her Majesty wore a cardiganAlthough Her Majesty wore a cardigan, although it was very hot.although Her Majesty - although it was very hot -wore a cardiganalthough Her Majesty wore - although it was very hot - a cardiganalthough

Although Her Majesty wore a cardigan, it was very hot

Ideas

AlthoughAlthough it was very hot, Her Majesty wore a cardigan BecauseBecause it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

Compound Messages Compounded out of prior messages

Independent message: m i Dependent message: m d Status modifier: * Compound message: m c

m c : m d *, m i

Ambiguity

(In those days) Her Majesty wore a cardigan (Yesterday) Her Majesty wore a cardigan

(In those days) Her Majesty wore a cardigan (Yesterday) Her Majesty wore a cardigan

(In those days) Her Majesty wore a cardigan (Yesterday) Her Majesty wore a cardigan

m c : m d *, m i

AlthoughAlthough it was very hot, Her Majesty wore a cardigan BecauseBecause it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

Despite the fact that Mike Tyson is a convicted rapist, this government let him in Even if Grannie was gunned down this morning, she’s chirpy enough nowEven if If Oswald didn’t shoot Kennedy, somebody else didIf

Selection of ‘if’ grants accords the dependent message the status of an hypothesis

Which means: It is being treated as true… …whether or not it really is.

? Structure Truth Affirmation

m c : m d *, m i

Compound Messages cannot be True (or False)

AlthoughAlthough it was very hot, Her Majesty wore a cardigan BecauseBecause it was very hot, Her Majesty stripped off SinceSince there are no trees in Orkney, it is a desolate place UnlessUnless I have made a mistake, the answer is 42 Whether or notWhether or not you like them, carrots are good for you

Despite the fact that Mike Tyson is a convicted rapist, this government let him in Even if Grannie was gunned down this morning, she’s chirpy enough nowEven if If Oswald didn’t shoot Kennedy, somebody else didIf

m c : m d *, m i

The Independent message is affirmed outright, unless there is rational reason to think otherwise

Although it was very hot, Her Majesty wore a cardiganAlthough Because it was very hot, Her Majesty stripped offBecause Since there are no trees in Orkney, it is a desolate placeSince Unless I have made a mistake, the answer is 42Unless Whether or not you like them, carrots are good for youWhether or not

Despite the fact that Mike Tyson is a convicted rapist, this government let him in Even if Grannie was gunned down this morning, she’s chirpy enough nowEven if If Oswald didn’t shoot Kennedy, somebody else didIf

Logic

October 1928 The 20 th Century Limited

Waistcoat by Sally Bayley

THE END