Evaulauting Arguements 10/08/2013
When we are we make claims or assertions and back them up with reasons
there are 2 necessary components
a persuasive claim or assertion
at least one supporting reason
Every Argument has 1. A conclusion the statement being supported, your persuasive claim, premises
Truth: whether premises and conclusion correspond to the facts
Validity: whether the conclusion follows from the premises. The conclusion of valid arguments are the
logical consequences of its premises
Soundness: when the premises of an argument are true and the conclusion validly derived from them.
Unsound arguments: Unsound arguments can use valid reasoning but are based on untrue premises
An unsound argument can have true premises but invalid reasoning is used to draw the conclusion:
Sound arguments: use valid reasoning to reach the conclusion –
Only sound arguments have both true premises & conclusions Necessity and Sufficiency
when evaluating an argument you should ask yourself if the premises are necessarily true.
And if they are sufficient to prove the conclusion. That is, is there enough evidence
Almost all arguments have strengths and weaknesses: few are perfect and few
it would be unrealistic to demand that an argument be proven beyond any doubt or criticism
when evaluating an argument we are concerned with validity and truth
we are not interested in extra logical merits such as clarity, elegance, persuasiveness, or economy of
style, agrees with our opinion or if the argument is considered true.
Fallacies are the illusion of a good argument. They have the power to fool you into thinking that you are
agreeing with an argument for good reasons when you are actually agreeing for poor reasons
Fallacies must be explained, not simple identified
Make up your own definitions and explanations don’t depend on the textbook or slides. You will be allowed
to bring your notes into the test
Sometimes there may be 3 fallacies for a single premise
Even when argument contains fallacies the conclusion may be true There is no complete inventory of fallacies we will be covering approx. 20
You should only be using the info on slides, textbooks, etc.
1. Appeal to force or threat of force
Instead of offering reasons this fallacy threatens to use force to get another to do something to accept an
(You scare someone in to making you do something)
Instead of offering reasons to support a conclusion they persuade us by manipulating our emotions and
2.a Appeal to pity Don’t determine the defendant guilty because they have suffered enough
2.b Appeal to fear if you don’t find the defendant guilty, you may be his/her next victim
2.c Appeal to guilt or shameyou should make an exception or ill lose my scholarship fail out of
university 2.d appeal to flattery you should make an exception to my late assignment because you are such a
( Emotions aren’t always negative, can be positive)
3a)Opponent is insulted or abused the mayor is sexiest pig so we shouldn’t listen to his plans to reorganize
is effective because once the arguer is made to look suspicious, ridiculous or inconsistent, they seem
untrustworthy, and by extension their argument shouldn’t be trusted
sometimes is confused with question beginning epithet
3.b) circumstantial ad Hominem
Argument criticized on basis that it merely advocates the interests of the opponent
distinct from abusive ad hominem because focus is on persons circumstances or situation, not their
personal chracteristics Example: sure he opposes rent control, he owns two apartment buildings, dosen’t he?
3.c gult by association
instead of offering reasons, an opponents argument is discredited because she or he is the member of a
if you agree with therioes about global warming you must be a radical environmentalist
opponent, or person advocating a position, is accused of acting in a manner which contradicts that position.
Charge of hypocrisy pot calling the kettle back
3.e Poisoning the well
a physchological technique which aims to make it impossible for the opponent to reply or disagree
it dispenses with objections by making anyone who object appear foolish
or the opponent is discredited before they present their argument
a rebuttal seems to only strengthen the accusation
Anyone who has any sense would agree that gun control is necessary
Sometimes what appears to be an ad hominem fallacy is justified For example: if someone is testifying based on his or her experience
4. Shifting the burden of proof
When someone who introduces an argument, shifts the burden of proof to the critic rather supporting their
argument with reasons
Example: You will have to show me why I shouldn’t believe in astrology before I will consider giving it up
Not a fallacy if the opponent notes that the arguer has not supplied support for the argument and
5. Self evident truth
The arguer presents his or her position as selfevident and not requiring defense.
Indicator phrases: “it is self evident that”
“ it is obvious to everyone”
“ no one can deny that”
“it is common sense”
This man has lied his way out of far tougher situations than this. Obviously we shouldn’t listen to him.
6. Appeal to ignorance the listeners inability to disprove the conclusion is used as proof of the arguments correctness
“ You cant prove me wrong, therefore, I must be right” or “ If you cant prove it is right then it must be
Appealing to the lack of evidence
There must be extraterrestrial life. No one has proven there isn’t.
*the difference is appeal to ignorance appeals to a lack of evidence, while shifting the burden of proof is
7. Loaded presupposition
Also known as fallacy of many questions, fallacy of loaded questions or fallacy of complex questions
An argument is made which has a controversial presupposition buried within it.
Example: the scandalous goods and services. Tax introduced by the liberals needs to be rejected if the
country is to regain its economic health.
8. Circular reasoning
Instead of presenting reasons to support the conclusion, the premises merely resasserts the conclusion
in different words
Arguments that beg the questions are circular arguments
Example: the belief in god is universal because everyone belives in god. Miracles are impossible
because they cannot happen.
Question: MODR LECTURE #2 10/08/2013
9a) appeal to popularity we are told to accept something as true because it is widely believed
accepted or done MODR LECTURE #2 10/08/2013
Instead of reasons we are told to accept something as true because it is widely believed accepted or done
9b) Appeal to tradition
1. Appeal to common belief Mc dicks burgers are healthy because there popular
2. Appeal to common practice tradition and custom can be result of a history or oppression
The institution of marriage is as old as human history and thus must be considered sacred.
Everyone uses formal logic in teaching critical thinking so it must be the best way for students to learn
9.c Appeal to group membership or patriotism( mob appeal)
uses patriotism, repetition, sarcasm, innuendo, high mindedness to exploit our emotions
exploits our need to beong to a group and assures us that group is right flattering the or appealing
to their prejudices
The presentation is theatrical, repetition is used
Makes it difficult for us to disagree or express the opposite opinion
For if we disagree we are excluded from the group
All individuals loyal to their country will agree with the security measures put in place since Sept. 11 .
I’m a working man myself, and I know how hard it is to make ends meet today.
Because you are a college audience, I know I can speak to you about difficult matters seriously. MODR LECTURE #2 10/08/2013
9.d appeal to novelty or change
somethings old fashioned so lets just toss it lets do something else
That’s oldfashioned and must be wrong.
Thomas Aquinas’ views on marriage may have been correct for his time, but they are dated and don’t fit the
values of the 20 century.
9.e Appeal to dislike or unusual or uncommon beliefs or habits
The majority of society is disgusted by sadomasochism, therefore it must be wrong.
Polygamy is rightfully disliked by most people.
9.f appeal to racial religious or social prejudice
We all know that homosexuals are…..
10. Appeals to authority
not always fallacious, can be good but their criteria have to meet
appeals to authority are a secondary way of getting evidence. You are being asked to e convinced
on someones word or authority
Criteria for good arguments from Authority
1 The authority has to be knowledgeable, trustworthy, and free of bias and their credentials should be
stated. MODR LECTURE #2 10/08/2013
The knowledge of the authority is current
3. Those credentials should be relevant to the argument
4. Authority shouldn’t be biased or stand to gain from their argument
Claim should be one with wide agreement among experts
If you like people, be sure you brush with Colgate. Walt Frazier wouldn’t think of brushing