Logical Fallacies Don’t ruin your argument with them. …Here are 18 (of many)
Logical argument structure • Premise 1: A = B • Premise 2: B = C • Conclusion: A = C • Logical fallacies occur when premises aren’t reasonable or conclusions use unsound reasoning.
Ad hominem • “To the man” • Attacking your opponent’s personal traits instead of the content of their argument.
Ad ignorantium • “To ignorance” • Stating something to be true simply because we cannot prove that it ISN’T true. Image source: http://www.telegraph.co.uk/news/newstopics/howaboutthat/ufo/9653499/UFO-enthusiasts-admit-the-truth-may-not-be-out-there-after-all.html
Anecdotal Evidence • Basing conclusions on personal experiences instead of empirical evidence. Image: http://thedailyomnivore.net/2013/01/16/anecdotal-evidence/
Appeal to Emotion • The manipulation of emotional responses instead of basing arguments on sound logic. http://pubcakes.com/blog/think-of-the-children
Argument from authority • Arguing that if an authority says something, its veracity is beyond doubt. http://www.funnyjunk.com/North+korea+master+race/funny-pictures/5218566/
Begging the question • Circular reasoning; using personal assumptions as sound logic • Interviewer: "Your resume looks impressive but I need another reference." • Bill: "Jill can give me a good reference." • Interviewer: "Good. But how do I know that Jill is trustworthy?" • Bill: “I can vouch for her." http://www.nizkor.org/features/fallacies/begging-the-question.html
Burden of Proof • Rather than proving that your claim is true, this fallacy puts the onus on your opponent to prove it is false. http://theosophical.wordpress.com/2011/04/18/bertrand-russell-and-the-celestial-teapot/
False Dichotomy • Alternatives are inaccurately limited to one of two choices. http://badquaker.com/archives/2914
Inconsistency • Arguments contradict each other. • A > B, B > C, C > A http://alltheragefaces.com/face/misc-jackie-chan
Loaded Question • Building acceptance of the answer into a question. http://www.nashvillecriminallawreport.com/articles/what-it-takes-to-be-a-great-cr/
Moving Goalposts • Explaining gaps in logic of an argument by clinging to rationalization of the argument’s value. • See: No True Scotsman
No True Scotsman • A form of moving the goalposts: doubting authenticity of counterarguments. • Person A: "No Scotsman puts sugar on his porridge." • Person B: "I am Scottish, and I put sugar on my porridge." • Person A: "Well, no true Scotsman puts sugar on his porridge."
Personal Incredulity • Negation of an argument due to lack of comprehension. http://modernmouseradio.com/2014/03/24/monday-memes-mike-wazowski-cant-believe-the-giant-hashtag/
Post hoc ergo propter hoc • Implying causal relationship when there is none. • Equating causality with correlation.
Red Herring • Focusing on a non-issue instead of the argument at hand
Slippery Slope • Negating arguments with unsubstantiated conjecture of consequences. • “If we allow gays to marry, soon it will be legal to marry robots.” http://www.electrogent.com/2012/08/argue-like-a-man-understanding-logical-fallacies-part-3/
Straw Man • Presenting an altered version of the opponent’s argument so that it seems absurd, then disproving the weak argument. http://badartcrit.tumblr.com/post/46325958071/how-not-to-react-to-criticism-the-strawman-reaction
TuQuoique • “You too” • Equating others’ lack of reasoning as proof/justification of your own. • Opponent A: • “You accepted bribes for your campaign!” • Opponent B: • “Well, so did you!”
Which fallacy? • If any aspects of evolution are not proven, creationism must be true. • I know I deserve an A in this course, especially because my grandma is sick and I’ve been working three jobs all semester. • “My doctor said Mylanta.” • “You can have a raise when you finish this project.” [project finished] “Your raise is dependent on many variables, not just that project, so you’ll have to wait.”
Which fallacy? • Lying is dishonest because it is deceitful. • Obama’s presidency is making Americans dumber. 2 years after he took office, graduation rates declined. • Heroin isn’t dangerous. My friend uses it often, and he’s just fine. • If we legalize marijuana, soon children will be forced to smoke it at school.
Sources • http://www.theskepticsguide.org/resources/logical-fallacies • https://yourlogicalfallacyis.com/ • http://writingcenter.unc.edu/handouts/fallacies/
