1. How to Argue without Cheating
Exploring Syllogisms and Avoiding Fallacious Reasoning

2. Today Goals Focus Questions What is an argument? What is a fallacy?
To investigate how to “delineate” an argument
To begin evaluating arguments
To look for valid reasoning
Determine if arguments use fallacious reasoning
What is an argument?
What is a fallacy?
How can we argue effectively?

3. How to Argue without Cheating
Arguing is fun
Whether it’s a persuasive essay, a formal debate, or unenthusiastic discussion with a parent over the precise moment at which the garbage should be removed, we humans like to argue.

4. Using Logic Generally, these arguments don’t seem to have much method.
You say this, they say that, and you go back and forth until somebody storms away. Little do you suspect that underneath this chaos, there is (or should be) a structure.
There are whole sciences devoted to making a good argument, and one of them, logic, gets down to the nitty-gritty of proving even a single point.

5. First Look:
In the world of logic, you can make a point (called the conclusion) by using two sentences called premises. Like so:
premise: All dogs have a liver.
premise: Froofi is a dog.
conclusion: Therefore, Froofi has a liver.
You may not be thrilled by this perky factoid, but in the world of logic, this syllogism is a slam dunk.

6. Syllogism All dogs have wings. Froofi is a dog.
Therefore, Froofi has wings.
Let’s consider: If all dogs had wings, Froofi would have wings.
The syllogism is valid. But dogs don’t have wings.
So although the syllogism is valid, the conclusion is false.
When the error is in the facts, not the logic, the argument is unsound.
When the facts are right, but the logic isn’t, the syllogism has a fallacy.

7. What’s a Logical Fallacy?

9. What is a Fallacy?
According to Webster’s Dictionary, a fallacy is an error in reasoning or a flawed argument.
It’s an argument that does not conform to the rules of logic, but appears to be sound.

11. Fallacy Example: Cheryl jumped inside the house.
Then the house collapsed.
Therefore, Cheryl made the house collapse.
Let’s say that happened.
The premises are true, but is the syllogism valid?
No. Even if Cheryl is a bit overweight, it’s unlikely she caused the house to collapse.
The syllogism is invalid.
It’s fallacious (it has a fallacy).
Your teacher won’t be happy. Nor will Cheryl.

12. Where Fallacies come in:
Fallacies become important within the premises, or the claims.
They also are important when reviewing the conclusion- can you come to this conclusion from these premises?
We will be going over common fallacies and their problems in logic.
You will be expected to know what the fallacy means, and apply it to a syllogism for your quiz (Friday, May 11th)

14. Fallacies we’ll cover Post Hoc Ergo Proctor Hoc Non Sequitur
Ad Hominem
Either/Or
Slippery Slope
Hasty Generalization
Red Herring
Ad Verecundiam
Bandwagon
Card Stacking
Circular reasoning

15. 1. Post hoc ergo propter hoc (aka Post Hoc)
After this, therefore, because of this
Just because Thing 1 happened before Thing 2, it doesn’t mean Thing 1 caused Thing 2

16. Post hoc ergo propter hoc
Ms. Bugica sneezed. Then her students laughed. Therefore Ms. Bugica’s sneezing makes her students laugh.

17. 2. Non Sequitor
“it does not follow”
The writer’s conclusion is not necessarily a logical result of the facts.

18. Non Sequitor

20. Attacks the person and the person’s character, not the issue
3. Argument Ad Hominem
“to the man”
Attacks the person and the person’s character, not the issue

21. Example:Ad Hominem

22. 4. Either/or “False Dilemma”
The writer tries to convince the reader that there are only two sides to an issue. Most reasonable people understand that there is often a middle ground, especially when dealing with complex issues.

24. The assumption that one thing lead to another after another
Slippery Slope
Chain reaction
The assumption that one thing lead to another after another

26. Jumping to conclusions about a population based on a small sample.
Hasty Generalization
Jumping to conclusions about a population based on a small sample.
Bases argument on insufficient data

28. Red Herring
Presenting an irrelevant topic to divert attention away from the original issue
(A red herring is a fish that smells really bad that people would use to distract bloodhounds)

29. Example: Red Herring

30. Ad Verecundiam argument from inappropriate authority
an appeal to the testimony of an authority outside the authority's special field of expertise.
From a logical point of view, anyone is free to express opinions or advice about what is thought true; however, the fallacy occurs when the reason for assenting to a statement is based on following the recommendation or advice of an improper authority.

31. Ad Verecundiam These can come from:
(1) experts in a particular field of knowledge (cognitive or epistemic authority);
(2) prestigious or powerful individuals or institutions;
(3) governmental, legal or administrative officials;
(4) social, family, religious, or ancestral heads; and so forth.
Oprah is reading this book, so you should too!
Wait, what makes her an “expert” at anything?

32. Bandwagon Appeal
Creates an impression that everybody is doing it, and so should you
In other words, if you suggest that someone’s claim is correct simply because it’s what most everyone is coming to believe, then you’re committing the bandwagon fallacy.

34. Card Stacking
The writer selects only data that supports his own viewpoint and ignores contradictory data

35. Card Stacking
They’re still fries!!!! !!!!!!!!! !!

36. Circular Reasoning A claim which contains it’s own evidence
Can often be said both ways, and proves nothing.
You can trust me because I would never lie to you.
I would never lie to you because you can trust me.

38. Let’s try some! #1
Trees have roots fact/error This maple is a tree. Fact/error Therefore, this maple has roots. Valid/invalid ___________________________sound/unsound
X has Y
Z is X
=Z has y

39. Let’s try some! #2
Birds can fly fact/error Airplanes can fly. Fact/error Therefore, airplanes are birds. Valid/invalid ___________________________sound/unsound
X can Y
Z can y
=Z are X

40. Let’s try some! #5 X has Y All Y is Z =X’s Y are Z
Kangaroos have pouches. fact/error All pouches are made of denim. Fact/error Therefore, kangaroos pouches are denim. Valid/invalid ___________________________sound/unsound
X has Y
All Y is Z
=X’s Y are Z

41. https://www. youtube. com/watch
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