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Negation Rules

Discover the power of negation rules, reductio ad absurdum, and indirect proof in logical reasoning. Learn how to use dash in and dash out effectively to construct sound arguments and prove statements. Enhance your critical thinking skills with practical examples and techniques.

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Negation Rules

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  1. Negation Rules Reductio Ad Adsurdum Indirect Proof Dash In and Dash Out

  2. Negation Rules Reductio Ad Adsurdum Indirect Proof Dash In and Dash Out The basic idea: To prove A, Assume -A and derive a contradiction. Since -A leads to a contradiction, -A must be wrong, and so A must be right.

  3. Negation Rules Dash In and Dash Out An illustration: Eat your SPINACH. Why? Because if you don’t you won’t get DESERT.

  4. Negation Rules Dash In and Dash Out An illustration: Eat your SPINACH. Why? Because if you don’t you won’t get DESERT. -S>-D The parent hopes the child will conclude: S

  5. Negation Rules Dash In and Dash Out Eat your SPINACH. Why? Because if you don’t you won’t get DESERT. D A -S>-D A S

  6. Negation Rules Dash In and Dash Out Eat your SPINACH. Why? Because if you don’t you won’t get DESERT. D A -S>-D A -S PA S Child’s Fantasy

  7. Negation Rules Dash In and Dash Out Eat your SPINACH. Why? Because if you don’t you won’t get DESERT. D A -S>-D A -S PA -D >O D&-D &I S Child’s Fantasy

  8. Negation Rules Dash In and Dash Out Eat your SPINACH. Why? Because if you don’t you won’t get DESERT. D A -S>-D A -S PA -D >O D&-D &I S Contradiction! So S is the only choice.

  9. Negation Rules Eat your SPINACH. Why? Because if you don’t you won’t get DESERT. 1 1. D A 2 2. -S>-D A 3 3. -S PA 2,3 4. -D 2,3 >O 1,2,3 5. D&-D 1,4 &I 1,2 6. S 3-5 -O An Official Proof

  10. Negation Rules Eat your SPINACH. Why? Because if you don’t you won’t get DESERT. 1 1. D A 2 2. -S>-D A 3 3. -S PA 2,3 4. -D 2,3 >O 1,2,3 5. D&-D 1,4 &I 1,2 6. S 3-5 -O An Official Proof

  11. Negation Rules A PA : ?&-? -A -In -A PA : ?&-? A -Out -In and -Out a.k.a. Reductio Ad Adsurdum or Indirect Proof To prove a statement, assume the opposite and derive a standard contradiction: a statement of the form ?&-?

  12. Avoiding a Confusion A PA : ?&-? -A -In -A PA : ?&-? A -Out -In and -Out a.k.a. Reductio Ad Adsurdum or Indirect Proof Indirect Proof reasoning often confuses people.

  13. Avoiding a Confusion G = My client is guilty P = My client was in Paris. G>P The crime was in Paris -P A witness saw him in Houston G PA P >O P&-P &I -G -In

  14. Avoiding a Confusion G = My client is guilty P = My client was in Paris. G>P The crime was in Paris -P A witness saw him in Houston G PA P >O P&-P &I -G -In Sleepy Juror: The defense said: ‘Suppose my client is guilty’. So even his own lawyer thinks he is guilty.

  15. Avoiding a Confusion G = My client is guilty P = My client was in Paris. G>P The crime was in Paris -P A witness saw him in Houston G PA P >O P&-P &I -G -In How to present an Indirect Proof in Court.

  16. Avoiding a Confusion G = My client is guilty P = My client was in Paris. G>P The crime was in Paris -P A witness saw him in Houston G PA P >O P&-P &I -G -In How to present an Indirect Proof in Court: Give the PA to your opponent.

  17. Avoiding a Confusion A PA : ?&-? -A -In -A PA : ?&-? A -Out -In and -Out a.k.a. Reductio Ad Adsurdum or Indirect Proof To prove a statement, assume the opposite and derive a standard contradiction: ?&-?. For more click here

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