errare humanum est (to err is human)

1. errare humanum est (to err is human)

2. FALLACIES

3. PART 1: INDUCTIONvs.DEDUCTION

4. INDUCTION (S  G) • think “increase” (induction, increase) • from specific/particular instance or instances • to generalization • quantity: (#) sufficient # of items or people asked, sufficient data (stats) • quality: reliable source (authority), accurate & in-depth observation *PROBABILITY, not certainty*

5. INDUCTION BAD EXAMPLE: • You compare the prices of 4 textbooks at store #1 with those at store #2 and notice that the prices are higher at the former than at the latter. You conclude that store #1 is more expensive.

6. INDUCTION GOOD EXAMPLE: • A television documentary focuses on the issue of unwed teenage mothers in a particular city neighborhood. Four girls are interviewed and followed for several days. Then, a noted and respected sociologist who has studied thousands of unwed teenagers is interviewed, and she claims these four girls are representative of the many.

7. INDUCTION *INDUCTIVE FALLACIES: • wrong use of data— • insufficient sample (not enough people interviewed) • ignore evidence (other possibilities)

8. DEDUCTION (G  S) • think “decrease” (deduction, decrease) • from inductive generalization • to conclusion

9. DEDUCTION 3 Propositions of a Deductive Syllogism • 1) MAJOR PREMISE: • inductive generalization • “All” • All humans are mortal. *(“syllogism”: Greek, to calculate using logic)*

10. DEDUCTION 3 Propositions of a Deductive Syllogism • 2) MINOR PREMISE: • statement about a specific member of that group • “This” • My English professor is a human.

11. DEDUCTION 3 Propositions of a Deductive Syllogism • 3) CONCLUSION: • Major Premise + Minor Premise = Conclusion • 1 + 2 = 3 • S  G, G  S • “Therefore” • Therefore, my English professor is mortal.

12. DEDUCTION • If the MAJOR premise = absent or faulty induction, • if the MINOR premise = faulty observation concerning the individual at issue, • then conclusion = faulty, invalid. • HOWEVER, if the opposite is true, then the conclusion is a valid, strong one — stronger than induction. *CERTAINTY, validity, truth*

13. DEDUCTION *BAD EXAMPLE: • A man is sitting opposite you on a train. He has what appears to be chalk dust on his fingers, and you conclude that he is a teacher.

14. DEDUCTION *BAD EXAMPLE: • Major premise = “All men with chalk on their fingers are school teachers.” • Minor premise = “This man has chalk on his fingers.” • Conclusion = “Therefore, this man is a school teacher.”

15. DEDUCTION *BAD EXAMPLE: • Faulty Conclusion: • other occupations: • draftsmen, carpenters, • tailors, artists • other powders: • flour, confectioner’s sugar, • talcum, heroin

16. DEDUCTION *DEDUCTION & your INTRODUCTORY PARAGRAPH • “Funnel Effect,” “Inverted pyramid” • G  S, • syllogism, conclusion of syllogism = thesis statement • Major premise = “Reducing awareness of social differences is a desirable goal for the school.” • Minor premise = “A uniform dress code would help to achieve that goal.” • Conclusion/thesis = “Therefore, students should be required to dress uniformly.”

17. DEDUCTION *DEDUCTIVE FALLACIES: • failure to follow the logic of a series of statements • an error in one premise or both premises • other possibilities exist that were not taken into consideration • reliance upon support other than facts

18. PART 2: FACTSvs.IMPLICATIONS, ASSUMPTIONS, INFERENCES *OCCAM’S RAZOR*

19. FACTS vs. OTHERS 1) FACTS: • provable, verifiable * • probable • primary evidence: • senses • science • secondary evidence: • testimony = secondary (beliefs, ideas not from senses) • historical evidence (documents, testimony, articles)

20. FACTS vs. OTHERS 2) IMPLICATIONS: • unspoken message • suggestion • with indirect words * SUBTEXTS * Rhetorical Questions, Mincing Words

21. FACTS vs. OTHERS 3) ASSUMPTIONS: • supposition • idea taken for granted • based on prior knowledge • based on little knowledge

22. FACTS vs. OTHERS 4) INFERENCES: • logical deduction • based on evidence or observation • educated guess

23. FACTS vs. OTHERS • ASSUMPTION vs. INFERENCE: • assumption = based on belief • inference = based on sense data or premises • IMPLICATION vs. INFERENCE: • implication = made by the speaker • inference = made by the listener

24. FACTS vs. OTHERS *Implications, Assumptions, Inferences: • not = facts • you fill in the gaps • you make connections • you supply missing data • you draw conclusion without all of the information/facts

25. OCCAM’S RAZOR *RULE OF SIMPLICITY: (in textbook) • When there are competing possibilities, choose the answer that requires the fewest assumptions. • “Cut” through the obfuscation (BS) and choose the solution that would not appear on The X-files . *The simplest solutionis often the best.

26. PART 3: THE FALLACIES

27. I. INSUFFICIENT EVIDENCE

28. INSUFFICIENT EVIDENCE • FAULTY INDUCTION: Inductive Fallacies • quantity: not enough evidence upon which to draw a reasonable conclusion • quality: unreliable data or sources • bad Ethos • implications, assumptions, inferences (not facts) • FAULTY DEDUCTION: Deductive Fallacies • flawed Major Premise (generalization) • flawed Minor Premise (specific, observation)

29. INSUFFICIENT EVIDENCE 1) OVERGENERALIZATIONS: • hasty, false, sweeping generalizations • dicto simpliciter (spoken simply) • implies ALL • uses INDEFINITE PRONOUNS: • all, everyone, everybody • no one, nothing • everything, anything, always

30. INSUFFICIENT EVIDENCE 1) OVERGENERALIZATIONS: • EASILY DISPROVED: too many exceptions and too many complications (life = too complex) • QUALIFY WITH: • many, some, few • usually, often, in my experience • DANGER with qualifying: too many maybe’s in your writing may make you look indecisive

31. INSUFFICIENT EVIDENCE *EXAMPLES of OVERGENERALIZATIONS: • *stereotypes, prejudices, superstitions: • racism, ageism, sexism • “Teenagers today are fat and lazy.” • “Men don’t cry.” • Hasty generalization: “Jim Bakker was an insincere Christian. Therefore, all Christians are insincere.” • Sweeping generalization: “Christians generally dislike atheists. You are a Christian, so you must dislike atheists.” (senior citizens, Asians, guys, Americans = materialistic, war-mongers)

32. INSUFFICIENT EVIDENCE 2) STACKING the DECK (a.k.a. “card stacking”): • poker metaphor: • dealing yourself a good hand; • stacking the card deck in your favor • selecting only the data that supports your position • ignoring contradictory data • (only 1 side of the issue) • (*needs other side/s of the issue) • news bias, politicians, tobacco/oil industries • fraudulent, misleading

33. INSUFFICIENT EVIDENCE *EXAMPLES of CARD STACKING: • “Ninety-five percent of the people I interviewed agreed with the Democratic Opposition.” • BUT I only interviewed people at the Democratic National Convention! • “According to a Left-Wing Nut magazine poll, the Vice President has a low approval rating.” • BUTonly those people who read—i.e., agree with the ideology of—this publication were polled.

34. INSUFFICIENT EVIDENCE 3) AD IGNORANTIUM: • since cannot disprove (or prove), then must be true • assumes a lack of information (“ignorance”) is a source of information (*needs more info) • yet, an absence of evidence is not evidence

35. INSUFFICIENT EVIDENCE • CARD STACKING vs. AD IGNORANTIUM: • Don’t be fooled by the “ignoring” part – • CS: purposefullyignoresexisting evidence • data that will disprove or weaken that side • the data does exist but is ignored • AI: uses ignorance as evidence • uses the lack of existing evidence as evidence • the lack of evidence = the proof • the data does not exist

36. INSUFFICIENT EVIDENCE *EXAMPLES of AD IGNORANTIUM: • “Since the library has no books on Eva Braun’s intimate relations with Adolf Hitler, then she must not have had any.” • “Of course the Bible is true. Nobody can prove otherwise.” • “Of course telepathy and other psychic phenomena do not exist. Nobody has shown any proof that they are real.” (aliens, ghosts)

37. INSUFFICIENT EVIDENCE 4) POST HOC ERGO PROPTER HOC: • “after this, therefore b/c of this” • assumes a causal relationship; • no other explanations • faulty Cause-Effect relationship • assumes a later event was caused by an earlier one • simply because of chronology • *needs more info, more research • B follows A; therefore, A causes B

38. INSUFFICIENT EVIDENCE • DISPROVE with: (more information) • prove A and B are merely coincidences • show how A is merely 1 cause of many • show how A is not even a significant cause of the many • *more than 1 cause of an effect, more than 1 effect of a cause • indirect and direct causes • complexity of life, of situations • OCCAM’S RAZOR: • simpler, more credible answer or explanation is best

39. INSUFFICIENT EVIDENCE • PHEPH: Superstitions • <boston.com >

40. INSUFFICIENT EVIDENCE *EXAMPLES of P.H.E.P.H.: • superstitions, astrology • Consider additional causes for the following: • “Because you left the milk out last night, it was spoiled this morning.” • “The Soviet Union collapsed after instituting state atheism. Therefore, we must avoid atheism for the same reasons.” • “A rooster crows every morning, and shortly after, the sun rises. Therefore, the rooster causes the sun to rise.”

41. INSUFFICIENT EVIDENCE *EXAMPLE of P.H.E.P.H.: • “After the school principal suspends daily prayers in the classroom, acts of vandalism increase, and some parents are convinced that the failure to conduct prayer is responsible for the rise in vandalism.” • But…decline in disciplinary actions, a relaxation of academic standards, a change in school administration, changes in family structure in the school community.

42. INSUFFICIENT EVIDENCE Post hoc ergo propter hoc: • after this (subsequency), therefore because of this Cum hoc ergo propter hoc: • with this (synchronicity), therefore because of this • mistakes a correlation for causation • overlooks coincidence, others causes • because of simultaneous occurrence • “Clinton had great economic policies because the economy was great during his two terms.”

43. INSUFFICIENT EVIDENCE 5) AD HOC: • “for this (specific purpose)” – “impromptu, provisional” • an after-the-fact explanation • does not apply to other situations (for this special case alone) • “God cured me of my cancer.” “But most patients with brain cancer die. Why did She save you? Are you special? Does She love you more than the rest of us?” “She moves in mysterious ways.” • because God treats all people equally, no special treatment • refuted by more evidence (radiation, medication, remission) • see also God & war, God & sports 1 time only!

44. INSUFFICIENT EVIDENCE 6) The Natural Law Fallacy -- Appeal to NATURE: • draws a false analogy between the human and natural worlds • assumes that humans are part of the natural world (animals) and should thus mimic “animalistic” behavior • assumes that whatever is “natural” or consistent with “nature” is good AND that whatever is “unnatural” is bad • supplements, herbal remedies • “law of the jungle” arguments for genocide, capitalism • “Homosexuality is natural because monkeys have been observed engaging in homosexual behavior.” (or the opposite)

45. INSUFFICIENT EVIDENCE 6) The Natural Law Fallacy -- Appeal to NATURE: • BUT • “natural” and “nature” = poorly defined • just because animals do it (or don’t) does not mean humans should (or shouldn’t) do so automatically, necessarily, unquestionably • naïve environmentalism • poison ivy, Ebola, climate, eat their young, eat bugs • bathrooms, plumbing, fire, literature, clothes, utensils

46. II. IRRELEVANT INFORMATION

47. IRRELEVANT INFORMATION DIVERSIONARY TACTICS • They introduce ideas that are off-topic. • Their data is NOT germane to the present case. Diversions, Distractions from the argument at hand

48. IRRELEVANT INFORMATION 1) AD BACULUM: • intimidation • threat of harm: • physical or psychological * • economical, political, environmental • extortion, blackmail • Rather than make a claim, point, or counter-argument, I make a threat, which isn’t discussing the issue at hand. • Because my evidence is rather weak, I try to win the argument with a “scare tactic.”

49. IRRELEVANT INFORMATION *EXAMPLES of AD BACULUM: • “If citizens don’t start patronizing downtown stores, then businesses will be forced to close and then the city will be in ruin.” • “If you don’t (believe in God, convert to our religion, illegalize that practice), then you’ll burn in Hell! • “... In any case, I know your phone number and I know where you live. Have I mentioned I am licensed to carry concealed weapons?” • “If we make abortions illegal, women will be getting butchered again in back alleys.” (ad misericordiam, slippery slope)

50. IRRELEVANT INFORMATION 2) AD HOMINEM: • *name calling • (think hombre, hommé) • personal attack, insults • attack the person, not the facts or issue • a way to avoid dealing with the issue (*diversion)