2. LECTURE OBJECTIVES & CA STATE
STANDARDS
• We will learn some common logical fallacies and
how to recognize them when reading texts.
Writing Standards:
Text Types and Purposes:
• 1. Write arguments to support claims in an analysis of substantive topics or texts, using valid
reasoning and relevant and sufficient evidence.
• b. Develop claim(s) and counterclaims fairly and thoroughly, supplying the most relevant
evidence for each while pointing out the strengths and limitations of both in a manner
that anticipates the audience’s knowledge level, concerns, values, and possible biases.
3. • A QUICK EXAMPLE OF
A LOGICAL FALLACY…
• FROM
• THE SIMPSONS
4. WHAT IS A LOGICAL FALLACY?
• Fallacies are common errors in reasoning that
will undermine the logic of your argument.
Fallacies can be either illegitimate arguments
or irrelevant points, and are often identified
because they lack evidence that supports their
claim. (Purdue OWL)
7. 1. SLIPPERY SLOPE
• A slippery slope fallacy occurs when someone makes
a claim about a series of events that would lead to
one major event, usually a bad event. In this fallacy, a
person makes a claim that one event leads to
another event and so on until we come to some
awful conclusion. Along the way, each step or event
in the faulty logic becomes more and more
improbable. (OWL EXCELSIOR)
9. 2. POST HOC ERGO PROPTER HOC
• The Latin phrase "post hoc ergo propter hoc"
means "after this, therefore because of this." The
fallacy is generally referred to by the shorter phrase,
"post hoc.” (Palomar.edu)
• This is a conclusion that assumes that if 'A' occurred
after 'B' then 'B' must have caused 'A.’ (OWL
Purdue)
11. 3. STRAW MAN
• A straw man fallacy occurs when someone
takes another person’s argument or point,
distorts it or exaggerates it in some kind of
extreme way, and then attacks the extreme
distortion, as if that is really the claim the first
person is making. (OWL Excelsior)
13. A FEW QUESTIONS…
• Which fallacy did Homer Simpson use in the
video from the beginning of this lecture?
• Which of these logical fallacies have you seen
before?
