In her famous 1947 essay “The Lost Tools of Learning,” Dorothy Sayers wrote:



“Has it ever struck you as odd, or unfortunate, that today, when the proportion of literacy throughout Western Europe is higher than it has ever been, people should have become susceptible to the influence of advertisement and mass propaganda to an extent hitherto unheard of and unimagined?”



Part of the reason for the susceptibility is that most students today are no longer taught logic in school — something that used to happen in the middle school curriculum. As a result, public figures, organizations, and those we discourse with are able to regularly commit logical fallacies without the majority of people questioning them.



Here are 5 of the most common logical fallacies you come across today: 



1. Ad hominem — Most of you are all-too-familiar with this one, and probably see it daily on Facebook. It’s Latin for “toward the man,” and it means personally attacking someone rather than engaging their arguments.





2. Tu quoque — Latin for “you too.” It’s frequently used by children, but you also see it used by adults as well to point out hypocrisies. Example:



Why is it a logical fallacy? Because, in this case, pointing out the hypocrisy (though kind of funny) is not a valid argument against curbing oil usage for the sake of the environment. 




3. Straw man — Overstating or misrepresenting someone’s argument so that you can more easily refute it. 




[Credit for the example: The Non Sequitur]



4. Argument from authority — Because a famous or respected source said or did something, it must be true/good. It’s used frequently in advertising. 




[Credit for the example: Chris Perley’s Blog]



5. Either/or fallacy — Presenting two extreme options as the only possibilities, thus limiting your opponent’s options.



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