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Introduction to critical thinking


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A simple Introduction to what is critical thinking & how to think critically.

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Introduction to critical thinking

  1. 1. Introduction to Critical Thinking by Nalaka Gamage Aurora Computer Studies ( Aurora Computer Studies 1
  2. 2. Agenda • What is critical thinking? • How to practice critical thinking? Aurora Computer Studies ( 2
  3. 3. What is critical thinking? Aurora Computer Studies ( 3
  4. 4. What is critical thinking? • Critical thinking is the ability to think clearly and rationally about what to do or what to believe. Aurora Computer Studies ( 4
  5. 5. What is not critical thinking? • Mere criticize everything • Thinking a lot Aurora Computer Studies ( 5
  6. 6. What hinder critical thinking • Lack of awareness/practice of rational (logical) thinking o Those ignorant of how to think critically • Personal biasness o Some people deliberately avoid critical thinking on situations where out come may put him in unfavorable situation • Inherited opinion/Cultural biasness o Most of the people die with the opinions they inherit from parents and close ones o Example : More than 80% of those who born Islam will die as Islam Aurora Computer Studies ( 6
  7. 7. What hinder critical thinking • Intellectual arrogance o Arrogance due to one’s education level or qualifications refusing to think critically in open situations • Intellectual laziness o Just lazy to think critically • Black & white thinking o Those who think in one of the extremes without considering all the intermediate possibilities Aurora Computer Studies ( 7
  8. 8. Attribute of critical thinkers • Rational • Think extra yard than others • Demand reasoning • Open minded • Ask right questions Aurora Computer Studies ( 8
  9. 9. Attribute of critical thinkers (con.) • Do not take anything for granted • Do not jump into conclusions • Do not fear challenging politically/culturally dominant fallacies Aurora Computer Studies ( 9
  10. 10. How to practice critical thinking? Aurora Computer Studies ( 10
  11. 11. Critical thinking steps Analyze Reasoning Evaluate Validate Conclude Aurora Computer Studies ( 11  Use formal logic  Use scientific knowledge  Look for real world examples 
  12. 12. How to do critical thinking? 1. Do careful, intentional thinking 2. Analyze & evaluate each piece of the argument o Identify facts and opinions o Evaluate the opinions 3. Use of reason or logic to check the validity 4. Check truthfulness of each fact to see if it is a sound argument 5. Application/test with real world scenarios to verify Aurora Computer Studies ( 12
  13. 13. Fact vs. opinion Aurora Computer Studies ( 13
  14. 14. Fact vs. Opinion Fact • A statement of fact can be proved TRUE or FALSE using standard knowledge o An observable or obvious thing o It has been proved by scientific experimentation o Can be deduced by formal logic • Example o Earth is round o Smoking causes cancer o There is a force towards the earth Aurora Computer Studies ( 14
  15. 15. Fact vs. Opinion Opinion • A statement of opinion is what someone believes or thinks o He must provide enough evidence to prove his opinion • Called burden of proof o We have to test if that opinion is valid or not o If we do not accept the opinion we must show the fault in the opinion • We do not have to prove that opinion is false o We may or may not provide alternative opinion • Example o There is life after death o Mr. X is a better leader than Mr. Y Aurora Computer Studies ( 15
  16. 16. Reasoning techniques Aurora Computer Studies ( 16
  17. 17. Reasoning techniques • Deductive Reasoning o Determines whether the truth of a conclusion can be determined for that rule, based solely on the truth of the premises o The Best approach  • Inductive Reasoning o Attempts to support a determination of the rule o Use with care  • Abductive Reasoning o a.k.a. inference to the best explanation, selects a cogent set of preconditions o Use with care  Aurora Computer Studies ( 17
  18. 18. Deductive reasoning Aurora Computer Studies ( 18
  19. 19. Deductive Reasoning • Derive logically necessary conclusion from given premises/ assumptions o Determines whether the truth of a conclusion can be determined for that rule, based solely on the truth of the premises • Mathematical logic and philosophical logic are commonly associated with this type of reasoning. Aurora Computer Studies ( 19
  20. 20. How to come to judgements? • Using formal logic o Example 1: X > 4 y > x Therefore y >4 o Example 2: "When it rains, things outside get wet.” “The grass is outside.” Therefore, when it rains, the grass gets wet. • Using scientific knowledge o Example: Removing oxygen will extinguish fire Covering with blanket remove/block oxygen Therefore, Covering with blanket will extinguish the fire Aurora Computer Studies ( 20
  21. 21. What is an argument? • An argument is set of assumptions/ premises followed by a conclusion • Example: Socrates is a philosopher. (Assumption) All philosophers like thinking. (Assumption) Therefore Socrates likes thinking. (Conclusion) Aurora Computer Studies ( 21
  22. 22. Outcome of an argument Argument Valid Sound Unsound Invalid Aurora Computer Studies ( 22   
  23. 23. What is a valid argument? • An argument is said to be valid if the conclusion is logically true, whenever all the assumptions/premises are true • Example o Valid argument If there is an earthquake, the detector will send a message. No message has been sent. So there was no earthquake. o Invalid argument Whenever Anil is here, Kumar is also here. Anil is not here. So Kumar is not here. Aurora Computer Studies ( 23
  24. 24. What is sound argument? • If an argument is valid and all the assumptions are found/proved to be correct, then the argument is said to be sound. • We must accept only the sound arguments! Aurora Computer Studies ( 24
  25. 25. Valid & sound deductive argument - example If husband is the president, then she is the first lady. Barack is President of the USA. Michelle is the wife of Barack. => Therefore, Michelle is First Lady. This argument is valid & sound. Aurora Computer Studies ( 25
  26. 26. Valid but not sound deductive argument - example If the moon is made of green cheese, then astronauts can eat moon rocks. The moon is made of green cheese. => Therefore, astronauts can eat moon rocks. This argument is valid but unsound. Aurora Computer Studies ( 26
  27. 27. Invalid deductive argument - example If Abraham Lincoln died of cancer, then Lincoln is dead today. Lincoln is dead today. => Therefore, Abraham Lincoln died of cancer. (This argument is invalid.) Aurora Computer Studies ( 27
  28. 28. Inductive reasoning Aurora Computer Studies ( 28
  29. 29. Inductive Reasoning • Use patterns of concrete instances to arrive at a conclusion • Attempts to support a determination of the rule • It hypothesizes a rule after numerous examples are taken to be a conclusion that follows from a precondition in terms of such a rule o It’s a way of generalization through observation and careful systematic analysis Aurora Computer Studies ( 29
  30. 30. How to come to judgements? • By analyzing results of empirical data using concepts of statistics and probability o Above 50% chance: Strong Argument o 50% or Less chance: Weak Argument • Is the value considerably higher than average for a sample with particular feature • Example: "The grass got wet numerous times when it rained, therefore: the grass always gets wet when it rains." Aurora Computer Studies ( 30
  31. 31. Inductive Reasoning - caution • Use of smaller sample may lead to false conclusion • What is your visibility may be too narrow Aurora Computer Studies ( 31
  32. 32. Inductive Reasoning - caution Aurora Computer Studies ( 32 What you have seen is not close to reality in general.
  33. 33. Outcome of inductive reasoning Reasoning Strong Cogent Not cogent Weak Aurora Computer Studies ( 33   
  34. 34. Outcome of inductive reasoning • Strong inductive argument o The truth of the premises really does prove that the conclusion is probably true • Cogent inductive argument  o A strong inductive argument in which all the premises are actually true • Not cogent inductive argument  o A strong inductive argument in which at least one premise is false. • Weak inductive argument  o The truth of the premises really does not prove that the conclusion is probably true Aurora Computer Studies ( 34
  35. 35. Strong & cogent inductive argument - example Most recording artists have talent. Britney Spears is a recording artist. => Therefore, Britney probably has talent. This argument is strong and cogent. Aurora Computer Studies ( 35
  36. 36. Strong but not cogent inductive argument - example Most boys like to play sports. Britney Spears is a boy. => Therefore, Britney probably likes to play sports. This argument is strong but not cogent. Aurora Computer Studies ( 36
  37. 37. Weak inductive argument Britney Spears is a recording artist. Britney has blonde hair. => Therefore, most recording artists have blonde hair. This argument is weak. Aurora Computer Studies ( 37
  38. 38. Abductive reasoning Aurora Computer Studies ( 38
  39. 39. Abductive Reasoning • Abductive reasoning allows inferring a as an explanation of b • As a result, abduction allows the precondition a to be adduced from the consequence b (i.e. effect to cause) • Deductive reasoning and abductive reasoning thus differ in the direction in which a rule like " a entails b is used for inference. Aurora Computer Studies ( 39 Incomplete observation Best prediction (May be true)
  40. 40. Abadductive Reasoning - caution • Considerable risk of inferring wrong cause • You may infer A as the cause, whereas actual cause might be C in this case Aurora Computer Studies ( 40 A B C D . . P Q R . .
  41. 41. Overview of reasoning Aurora Computer Studies ( 41 General rule Specific conclusion (Always true) Specific observation General conclusion (May be true) Incomplete observation Best prediction (May be true) Deductive Reasoning Inductive Reasoning Abductive Reasoning
  42. 42. Other helpful techniques for critical thinking Aurora Computer Studies ( 42
  43. 43. Tools/techniques for critical thinking • Analysis, synthesis & application • What, Why & How? Approach • Abstraction • Root cause analysis Aurora Computer Studies ( 43
  44. 44. Analysis, synthesis & application Aurora Computer Studies ( 44 Analysis Synthesis Application
  45. 45. What, Why & How? approach Aurora Computer Studies ( 45 What? Why? How?
  46. 46. Abstraction Aurora Computer Studies ( 46
  47. 47. Abstraction - usages • Understanding mathematics • Design (model) before develop/ implement Aurora Computer Studies ( 47
  48. 48. Root cause analysis • We must try to understand the root causes rather than jump into consider immediate causes in order to solve problems • Ask why five times Aurora Computer Studies ( 48
  49. 49. Aurora Computer Studies ( 49
  50. 50. Root cause analysis - example The vehicle will not start. (the problem) Why? - The battery is dead. (First why) Why? - The alternator is not functioning. (Second why) Why? - The alternator belt has broken. (Third why) Why? - The alternator belt was well beyond its useful service life and not replaced. (Fourth why) Why? - The vehicle was not maintained according to the recommended service schedule. (Fifth why, a root cause) Aurora Computer Studies ( 50
  51. 51. References • • ing • oning • nduction • Aurora Computer Studies ( 51
  52. 52. You may also like following • If vs If and only if • Science, philosophy, religions and myths Aurora Computer Studies ( 52
  53. 53. Thank You ! Presented by Nalaka Gamage Aurora Computer Studies ( 53
  54. 54. "We are what we repeatedly do. Excellence, then, is not an act, but a habit." ~ Aristotle Aurora Computer Studies ( 54
  55. 55. Premier Study Center Aurora Computer Studies, Summerset College, # 135, 3rd Floor, DFCC Building, High Level Road, Maharagama. City Study Center Aurora Computer Studies, Summerset College, # 88/2, 2nd Floor, BOC Building, High Level Road, Kirulapone, Colombo 06 Details and enquiries : Call - 0719 842030 E-mail – Web - Aurora Computer Studies