1. What is Knowledge?

2. you must believe the knowledge statement your belief in the knowledge statement has to be true your true belief has to be justified. justified, true belief

3. Requires: Evidence – reasonable & positive evidence that supports & justifies belief. Coherence – does this fit with our current understanding? Can you see any problems with these requirements?

4. certainty Distinguishes knowledge from belief. Truth without doubt. Language Perception Reason Emotion I think, therefore I am

5. relativism No absolute objective truth Knowledge is relative to the individual, culture or society This may be safer for ethics, politics & religion. But what about maths and science? I knew the Earth was flat I know Santa Claus exists

6. But Sir – its just common sense...

7. Class size There are three classes in year 3. One class contains 12 students, one class contains 25 students, and one class contains 23 students. What is the average class size?

8. The teachers point of view The teacher has to teach 3 classes, one of 12 students, one of 25 students, and one of 23 students. Average class size = (12 + 25 + 23)/3 = 20

9. The students point of view There are 12 students in a class of 12. When asked the size of their class they will all say 12 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12. 25 students will say 25! 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25. 23 students will say 23! 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23.

10. The students point of view Average class size for a student = ((12 x 12) + (25 x 25) + (23 x 23))/(12 + 25 + 23) = 21.6 (Remember the average from the teachers point of view was 20!

11. Whens your birthday?

12. Birthday coincidence What is the chance/probabi lity that two people in a group of 23 randomly selected people have the same birthday?

13. Birthday coincidence We need to look at how many possible pairs there are. Person 1 and person 2 Person 1 and person 3 Person 1 and person 4 etc. There are 22 possible pairs with person 1

14. Birthday coincidence There are 22 possible pairs with person 1 Then person 2 with person 3 person 2 with person 4 person 2 with person 5 etc. There are 21 possible pairs with person 2

15. Birthday coincidence There are 22 possible pairs with person 1 There are 21 possible pairs with person 2 It follows there are 20 possible pairs with person 3, 19 with person 4, 18 with person 5 etc.etc.

16. Birthday coincidence The total number of different pairs of people is therefore; 22 + 21 + 20………….+ 3 + 2 + 1 = 253 Since there are 365 possible birthdays (well ignore 29 th February for simplicity!), the chance of two people having the same birthday is 253/365 = 0.69 (69%)

17. Birthday coincidence What is the chance/probability that two people in a group of 23 randomly selected people have the same birthday? 69% If there are over 30 people the chance is nearly 100%, worth a bet at a party!

19. Logical fallacies

20. The more churches there are in a city, the more prostitutes there are.

21. People who have a tattoo are more likely to develop lung cancer. This is true.

22. Connor says that he knows someone who is 90 and who has smoked 40 cigarettes a day for 75 years and hes OK, so smoking cant be harmful.

23. Julie bought a good luck charm and he seems to be doing better at school.

24. Post hoc ergo propter hoc Assuming one thing causes another just because one follows another. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press

25. A summary of common fallacies

26. Ad ignorantiam Claiming that something is true because it cannot be proved to be false. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press

27. Hasty generalisation Generalising from insufficient evidence. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press

28. Ad hominem Attacking /supporting the person rather than the argument. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press

29. Circular reasoning Assuming the truth of what you are supposed to be proving. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press

30. Special pleading Using double standards to excuse an individual or group. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press

31. Equivocation Using language ambiguously. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press

32. False analogy Assuming that because two things are alike in one way that they are alike in other respects. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press

33. False dilemma Assuming that only a limited number of alternatives exist. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press

34. Loaded question A question that is biased because it contains a built-in assumption. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press

35. In each of the following cases, decide which best applies to the argument. Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

36. 1. Since strict gun control laws were introduced in Dodge City, the crime rate has risen. This shows that gun control does nothing to reduce crime. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

37. post hoc ergo propter hoc Since strict gun control laws were introduced in Dodge City, the crime rate has risen. This shows that gun control does nothing to reduce crime.

38. 2. Emmeline said she trusted me, and she must be telling the truth because she wouldnt lie to someone that she trusted. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

39. circular reasoning Emmeline said she trusted me, and she must be telling the truth because she wouldnt lie to someone that she trusted. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press

40. 3. Its OK to beat children to get them to behave. After all, if you want to make omelettes, you have to break eggs. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

41. false analogy Its OK to beat children to get them to behave.. After all, if you want to make omelettes, you have to break eggs.

42. 4. That cant be right, non of my friends would believe it. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

43. ad hominem That cant be right, non of my friends would believe it.

44. 5. Since many great scientists have believed in God, there must be some truth in religion. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

45. ad hominem Since many great scientists have believed in God, there must be some truth in religion.

46. 6. Teddy and Seanne got on very well on their two dates together. They are clearly well suited and should get married. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

47. hasty generalisation Teddy and Seanne got on very well on their two dates together. They are clearly well suited and should get married.

48. 7. Do you want to be part of the solution, or part of the problem? Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press

49. false dilemma Do you want to be part of the solution, or part of the problem?

50. 8. I agree that you shouldnt copy mp3s illegally, but Ive only copied a few and I do buy tracks sometimes. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

51. special pleading I agree that you shouldnt copy mp3s illegally, but Ive only copied a few and I do buy tracks sometimes.

52. 9. The average UK family has 2.5 children. The Smiths are average people, they must have 2.5 kids. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

53. equivocation The average UK family has 2.5 children. The Smiths are average people, they must have 2.5 kids.

54. 10. Since no-one has been able to prove that God didnt create the universe, we must conclude that God did make everything. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

55. ad ignorantium Since no-one has been able to prove that God didnt create the universe, we must conclude that God did make everything.

56. 11. Are all your family stupid, or is it just you? Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

57. loaded question Are all your family stupid, or is it just you?

58. 12. No scandal has ever touched Mr Porter. He must be a clean living and honest man. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

59. ad ignorantium No scandal has ever touched Mr Porter. He must be a clean living and honest man.

60. 13. Just as you are more likely to take care of a car that you own rather than a car that you rent, a slave owner would look after a slave better than an employer would look after their worker. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

61. false analogy Just as you are more likely to take care of a car that you own rather than a car that you rent, a slave owner would look after a slave better than an employer would look after their worker.

62. 14. To ignore the possibility that Norway landed the first person on the moon just because nobody has heard of a Norwegian space program is arrogant. If we are unaware of something does not mean that it never happened. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

63. ad ignorantium To ignore the possibility that Norway landed the first person on the moon just because nobody has heard of a Norwegian space program is arrogant. If we are unaware of something does not mean that it never happened.

64. 15. In the fight against terrorism, you are either with the USA or against. Theory of Knowledge for the IB Diploma, Richard van de Lagemaat, Cambridge University Press Hasty generalisation, post hoc ergo propter hoc, circular reasoning, ad hominem, special pleading, ad ignorantium, false dilemma, false analogy, equivocation, loaded question.

65. false dilemma In the fight against terrorism, you are either with the USA or against.

66. Good generalisations? So how do we make good generalisations?