PHIL 150 Chapter Notes - Chapter 4, A-C: Formal Fallacy, Informal Fallacy, Fallacy
10 May 2018
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PHIL Logic Reading Notes: Chapter 4 Informal Fallacies (A-C)
Wireless Philosophy (Ad Hom, Ad Hom 2, Appeal to the People)
A. Why Study Fallacies?
Formal fallacy: A logical error that occurs in the form or structure of an argument
o It is restricted to deductive arguments
Informal fallacy: A mistake in reasoning that occurs in ordinary language and is different from an
error in the form or structure of argument
o Some of these fallacies are persuasive because they involve fear, anger, pity and other
emotional appeals
o Defect in the content of the argument
Recognition and the ability to expose the reasoning flaws in fallacies arms you against the
psychological power of persuasion
Fallacies: Instances of flawed reasoning whose premises do not offer good grounds for believing
the conclusion
B. Fallacies Based on Personal Attacks or Emotional Appeals
Truth of state or strength of argument should be judged objectively
Reject an argument based on truth value analysis or logical analysis
Four types of fallacies based on personal attacks
1. Ad Hominem Abusive: Fallacy is distinguished by an attack on alleged character flaws of a
person instead of the person’s argument
o Reason to reject someone’s statement is based on irrelevant information rather than on the
merits of the advice and the strength of the argument
2. Ad Hominem Circumstantial: When someone’s argument is rejected based on the
circumstances of the person’s life
o Circumstances, not character (like ad hominem abusive)
o Ex: political affiliation, educational institution, place of birth, religious affiliation, and
income
3. Poisoning the Well: The fallacy occurs when a person is attacked (based on her character or
life) before she has a chance to present her case
4. Tu Quoque: The fallacy is distinguished by the specific attempt of one person to avoid the issue
at hand by claiming the other person is a hypocrite
o Translates into look who’s talking
We can still use personal attacks/history to doubt the argument, but not completely falsify the
argument
Types of fallacies based on emotional appeals
5. Appeal to the People: The fallacy occurs when an argument manipulates a psychological need
or desire so a reader or listener will accept the conclusion
o a) Group solidarity: using an emotional response based on the power of one’s connection to
a group
▪ Ex: We must not let our country be taken over by illegal aliens!
▪ Kind of similar to mob mentality
▪ Sometimes used in poll questions to skew people’s opinions
o b) Bandwagon effect: draws on the individual’s desire to belong to a popular group
▪ Emotions involved in joining a movement merely because it is popular
▪ Everyone else is doing it
o c) Belonging to an exclusive and/or elite group
▪ Different from bandwagon – desire to be part of a small elite group instead of the
group
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