1. FALLACIES COMMON AND RECURRENT ERRORS IN REASONING
IMPORTANT STRATEGY TO IDENTIFY THEM: TREAT PASSAGE AS AN ARGUMENT WITH PREMISE AND CONCLUSION AND DETERMINE WHAT SORT OF STRUCTURE IT FOLLOWS.

2. THE TWO CLASSES
Irrelevant Premises
Unacceptable Premises

3. IRRELEVANT PREMISES GENETIC FALLACY
Origin of claim used as reason why claim is true or false
Source of claim is irrelevant to its truth
“Russell’s idea about job creation was produced when he was in a drunken state, so it must be flawed.”

4. COMPOSITION COMPOSITION: P IS TRUE OF ONE PART OF SOMETHING
P IS TRUE OF THE WHOLE THING
Watch for context of statistics!

5. DIVISION Flip side of composition P IS TRUE OF THE WHOLE THING
P IS TRUE OF ONE SPECIFIC PART OF THING

6. APPEAL TO THE PERSON Ad hominem (to the person) Structure:
X SAY P + X HAS SOME NEGATIVE TRAIT
P IS NOT TRUE
FORMS:
CRUDE FORM: NAME CALLING AND INSULTS

7. OTHER FORMS AND SPECIES OF AD HOMINEMS
TU QUOQUE “YOU’RE ANOTHER” OR THE POT CALLING THE KETTLE BLACK
(hypocrisy)
POISONING THE WELL:
X HAS A VESTED INTEREST IN THE TRUTH OF P
P IS UNTRUE

8. EQUIVOCATION EQUIVOCATION (MANY VOICES)
SWITCHING MEANING OF WORD IN MIDSENTENCE OR IN ARGUMENT, EITHER PREMISES OR CONCLUSIONS.
PLAY ON WORD MEANING
P. 174 EXAMPLE

9. APPEAL TO POPULARITY Also called “appeal to majority” Structure:
Everyone (or almost everyone) believes X,
X is true
“The vast majority of Canadians believe that the monarchy is a good thing.”
Therefore …

10. APPEAL TO TRADITION
Truth of claim is dependent on being part of tradition
Also similar to “subjectivism”
Subjectivism: “I belief X, therefore X is true.”
“I was brought up to believe that X is true, therefore X is true”
“Acupuncture has been used for a thousand years in China. It must work.”

11. APPEAL TO IGNORANCE Use of lack of evidence for support of claim
TWO STRUCTURES:
1. P HAS NOT BEEN PROVED FALSE
P IS TRUE
2. P HAS NOT BEEN PROVED TRUE
P IS FALSE

12. APPEAL TO IGNORANCE, cont.
Scientific research and justification when evidence is lacking
Burden of Proof
When burden of proof is placed on wrong side!
Burden always falls on claimant
A form of baiting

13. APPEAL TO EMOTION STRUCTURE: AN EMOTIONAL RESPONSE OCCURS DUE TO P
P IS TRUE OR P IS FALSE

14. RED HERRING
USE OF HERRINGS TO DIVERT THE SMELL OF A HOUND DOG AWAY FROM THE CRIMINAL’S PATH.
FORM 1.
PROPOSITION P IS TRUE
PROPOSITION Q IS TRUE

15. RED HERRING, continued FORM 2.
THERE IS GOOD REASON TO BELIEVE Q IS TRUE
P IS TRUE

16. STRAW MAN
MISREPRESENTATION, DISTORTION, OVERSIMPLIFYING AN ARGUMENT OR CLAIM OR THEORY TO WEAKEN IT AND FIND IT FAULTY.
Structure:
Reinterpret claim X so it is weak or absurd
Claim X is faulty of untrue

17. FALLACIES WITH UNACCEPTABLE PREMISES
Begging the Question or Circular Argument
Structure:
P (a claim is made)
P (same claim is made)
SAME CLAIM IS PREMISE AND CONCLUSION!

18. BEGGING THE QUESTION, cont.
Bible says that God exists
Therefore, God exists
Why is Bible to be accepted? (asking for evidence for premise)
Because God exists. (Use of conclusion as premise for first premise)

19. FALSE DILEMMA (ALTERNATIVE)
Presents only 2 alternatives, rejects one so as to assert the other.
Disregard for other possibilities
“either those lights you saw in the night sky were alien spacecraft or you were hallucinating.”
“You were not hallucinating, therefore….”

20. FALSE DILEMMA cont. Sometimes applies to stand-alone phrases
e.g. “Microsoft: Bad cop or evil genius.”
“Jesus: lunatic or the son of God.”

21. Slippery Slope
Taking some step will lead down a slope towards some undesirable consequence
False consequence; appeal to fear
Structure:
Doing action X will lead to Y
Therefore, this will lead to Z, etc
Domino effect
e.g. Latimer case: Hunting season on the disabled.

22. Hasty Generalization
Drawing a conclusion about a group or about all events from the experience of one or an individual. (Stereotypes) (inadequate sample)
Structure:
One event or person y has X
Therefore all events or all persons of y have X

23. Faulty Analogy Context: argument by analogy
Fault: comparing different things or essentially different things as if they were sufficiently similar
E.g. Watch and Intelligent design