Logical+Fallacies

= A **//fallacy//** is a deceptive, false, or misleading argument, notion, belief, etc. = === __**//Formal Fallacies//**__ are characterized by the logical structure of an argument being flawed. The advertisement below is a kind of **//formal fallacy// called a //non-sequitur//** in which the conclusion does not follow logically from the previous argument or statement. Note that the conclusion: "We make Virginia Slims especially for women," does not follow logically from the statement: "Women are biologically superior to men." **//Formal Fallacies//** then are the result of //invalid// deduction and one could argue that all //invalid// deductive arguments are a form of **//non sequitur//**. Remember that we can use venn diagrams to visualize deductive thinking to determine if an argument is valid or invalid === = =

=== Another kind of //__formal fallacy__// that we have examined is concerned with inductive logic. The //Hasty Generalization// is the result of making a generalization on the basis of insufficient evidence and we have already seen that we are not always in agreement of what constitutes sufficient evidence. ===

=== __**//Informal Fallacies//**__ are reasoning that //seem// logical, but are actually Lazy logic. //**Informal Fallacies**// are characterized by premises that fail to support the proposed conclusion, but an argument is structured properly. So the argument looks valid (and could be). === = = =Here are some common Fallacies.=

= __Post hoc ergo propter hoc__ (after this, therefore this) =

In this kind of fallacy one is mistaking correlation for cause and effect (needs more evidence)
The following Post hoc fallacies use true statistics. There might be a causal connection but could there be another reason for the ‘connection’?
 * AS THE NUMBER OF CHURCHES IN THE USA INCREASES, SO DO THE NUMBER OF PROSTITUTES
 * CRIME IS INCREASING IN GERMANY, BUT SO IS THE NUMER OF COLLEGE GRADUATES. SO EDUCATION IS CORRUPTING THE YOUNG
 * THE HOMELESS MAN WAS SEEN IN FRONT OF THE SHOP BEFORE IT WAS ROBBED, SO HE DID IT

Ever since I've started presuming that correlation equals causation, Mr. Abizaid has been clean shaven. media type="youtube" key="-_0_suZntks" height="282" width="381"

=__ Circular Reasoning __ (begging the question) =

Assuming the truth of what you are trying to prove, BEFORE proving it
Can you find the unproven part of these arguments?
 * THE SOLDIER GAVE OUT THE GUNS, BUT KEPT AN EXTRA ONE FOR HIMSELF. WHEN ASKED WHY, HE SAID “I AM THE LEADER”. WHY ARE YOU THE LEADER? “BECAUSE I HAVE MORE GUNS”
 * I KNOW MY PRESIDENT IS A GOOD MAN, BECAUSE HE SAYS HE IS AND A GOOD MAN WOULD NOT LIE
 * I KNOW I AM SMARTER THAN YOU, BECAUSE IT WOULD BE FOOLISH TO SAY SO IF IT WASN’T TRUE, AND I AM NOT A FOOL.

Circular reasoning is the best fallacy and is capable of proving anything. Since it can prove anything, it can obviously prove the above statement. Since it can prove the first statement, it must be true. Therefore, circular reasoning is the best fallacy and is capable of proving anything.

=__Ad hominem fallacy__=

Attacking the person you disagree with or appealing with the person you agree/disagree with, instead of their argument

 * Ad hominem** fallacies are usually understood to be an attack on a person but they can also be seen as an "**appeal to authority,**" which we have said can be a //justification for a Knowledge Claim//. Should we allow **Appeals to Authority** as such?
 * AS HITLER'S INTEREST IN ART ATTESTS, THE LOVE OF ART IS A DANGEROUS ANTECEDENT TO FASCISM
 * EMINENT BIOLOGIST FRANK FENNER, WHO HELPED ERADICATE SMALLPOX, SAYS HUMANS WILL BE EXTINCT WITHIN THE NEXT 100 YEARS AND I AGREE.

Political advertisement that engages in an ad hominem attack. The advertisement raises some policy points but is mostly focused on attacks on Harold Ford’s character. media type="youtube" key="kkiz1_d1GsA" height="290" width="389"

Ad hominem is the best logical fallacy and if you don't agree with me, then you are a fool.

=__ Equivocating __=

This fallacy uses a word/idea with two different meanings in two different ways to support an argument

 * FRIES AND A COKE ARE BETTER THAN NOTHING, AND NOTHING IS BETTER THAN GOOD HEALTH, SO FRIES AND COKE ARE BETTER THAN GOOD HEALTH
 * SCIENTISTS SAY THAT RED WINE CAN PREVENT HEART DISEASE. I DRINK A BOTTLE EVERY NIGHT, SO I MUST HAVE A REALLY HEALTHY HEART.
 * THERE ARE LAWS OF NATURE, AND LAWS ARE CREATED BY LAWGIVERS, SO A COSMIC LAWGIVER LIKE GOD MUST HAVE CREATED THE LAWS OF NATURE.

=__Arguing using ad ignorantium__=

Arguing using ad ignorantium is a very common logical error!

 * IF THERE ARE PARTS OF SCIENCE WE CAN’T UNDERSTAND YET, THEN THAT PROVES THERE IS A GOD (because only something smarter than ourselves could have created something we can’t understand)
 * THERE ARE MILLIONS OF THINGS WE CAN BELIEVE IN (FAIRIES, MAGIC, UNICORNS ETC.). JUST BECAUSE WE CAN’T PROVE THEM, DOES THAT MEAN THEY CAN'T EXIST?
 * CAN YOU THINK OF THEORIES (CONSPIRACY) THEORIES) THAT PEOPLE USE TO DEFEND DIFFICULT TO PROVE/EXPLAIN CONUNDRUMS?

You cannot prove that Ad ignorantium arguments weren't created by the extraterrestrials that built the pyramids so it must be true.

=__ The false dilemma __=

Binary thinking-black/white thinking. This fallacy presents a limited choice as the only possible options when there may be many other choices/conclusions.
media type="youtube" key="-23kmhc3P8U" height="282" width="376"
 * IF YOU DON’T LET ME GO TO THIS PARTY, I’LL BE A TOTAL LOSER AT SCHOOL
 * ARE PEOPLE WHO WANT TO SPEND MONEY ON THE MILITARY AWARE THAT WE’LL HAVE TO CLOSE SCHOOLS AND HOSPITALS?
 * IF YOU ARE AGAINST THE WAR IN IRAQ, THEN YOU MUST HATE AMERICA.
 * IF YOU ARE ARAB AND ANTI-ISRAEL, YOU MUST BE A TERRORIST SYMPATHIZER

Watch your thinking! The world is more than shades of grey than black and white.
Either he is arguing a false dilemma fallacy or he is a maniac.

=__ The loaded question __=

Contains a built in assumption
CAN YOU PHRASE THE QUESTIONS ABOVE IN A MORE NEUTRAL/UNBIASED WAY? media type="youtube" key="G0ZZJXw4MTA" height="315" width="420"
 * DO YOU ALWAYS CHEAT ON EXAMS?
 * DID YOU BEAT YOUR STUDENTS TODAY?
 * WHY DO YOU HATE AMERICA AND FREEDOM SO MUCH?
 * ARE YOU AWARE THAT OBAMA IS A SOCIALIST?

= There are a lot more logical fallacies that you can explore [|here], [|here], and [|here]. =

media type="youtube" key="fXLTQi7vVsI" width="560" height="315" =A Great Series on Logic and Critical Thinking= media type="youtube" key="iSZ3BUru59A" height="315" width="560"

= Logical Fallacy 60 Second Challenge =


 * Write a dialogue, argument, song, skit, playlet, etc. that uses as many logical fallacies as possible. Practice performing it. It should be no more than 60 seconds long.
 * You may choose to work in groups of up to three.
 * RECORD YOUR MASTERPIECE or perform it live in class.
 * Turn in script/lyrics identifying all of the fallacies you used and a fallacy count
 * Sock puppets are encouraged!

Prizes for the presentation of most fallacies (in an amusing manner).

=Student Example= media type="youtube" key="OiJAQIRB8tY" width="560" height="315" = =