Informal argument

Informal argument



Informal argument, informal logic, logical fallacy, and formal fallacy are all terms covering much the same area: how arguments ought to be constructed, what counts as evidence, and what sort of reasoning is valid or invalid.

0.  Form small groups, max. 3.

1. Many of the most common forms of invalid or otherwise faulty types of logic have been named.  Chose five of the fallacies from the list below.  Define them in plain English using your own words, and give an example argument that commits the fallacy, explaining how the fallacy manifests in the example argument.  Time permitting, some groups may present, (PPT format recommended).

ad hominem

ad populum

appeal to authority

begging the question

hasty generalization

post hoc ergo propter hoc

correlation does not imply causation

strawman

ad baculum

false dichotomy

loaded question

red herring

fallacy fallacy

slippery slope

non-sequitur

bandwagon fallacy

argumentum ad ignorantiam

equivocation

weasel words

narrative fallacy

2. Categorize as many of the following arguments by fallacy type as you can.  Note your justification.

a) "Princess Kate wears Alexander McQueen. Are you trying to say you have better fashion sense than a royal princess?"

b) "We need to stop allowing colleges to increase tuition every year. The next thing we know, it's going to cost more to attend college for one semester than it is to buy a new home!"

c) "You are so stupid your argument couldn't possibly be true."

d) "No true Scotsman puts sugar on his porridge."

e) "Everyone else is doing it.  Why shouldn't you?"

f) "Mary wore her favorite necklace today and aced her spelling test. That necklace must be lucky. "

g) "Veganism is foolish because humans have eaten meat for thousands of years."

h) "I am a good student, Frank says so.  How can we trust Frank?  Simple:  I will vouch for him."

i) "People say salmon are disappearing from this river.  Let's watch and see if one disappears."