Critical Thinking Episode 2: Fallacies

Critical Thinking Terms # 2:  Fallacies and the fallacy of “argument from ignorance”


A quick warning when you try to get kids to learn about critical thinking: Be careful when you train your adolescent to spot fallacies! You may empower them to thwart you and make you look silly.  But it’s worth it if you want them to be inspired critical thinkers.  Inspired critical thinkers are sometimes annoying… just ask Socrates’ accusers. 


A fallacy is an error in logic.  There are many kinds of fallacies and they all have names… which makes them fun to spot. They are sometimes made intentionally to trick people and other times by accident with no ill intent. The first one we will consider is call the argument from ignorance.


An argument from ignorance can come up when people don’t follow the burden of proof rule… see earlier post.  (The person making the proposition is responsible for providing evidence.) 


Here is how it might happen in real life:


Bobby: There is intelligent life in outer space. (Proposition)


Cindy: Oh, that’s interesting. I don’t have any proof that there isn’t life in outer space. (Expresses ignorance on the matter)


Bobby: So that settles it!  There is life in outer space. (Fallacy of argument from ignorance.)


Cindy: That is so amazing.  I wonder what planet the extraterrestrials are living on! (Cindy forgets her critical thinking skills and accepts Bobby’s proposition.)


The point here is not that there is or isn’t life in outer space, it is that Bobby and Cindy are not being inspired critical thinkers like we want Bolinas-Stinson students to be.  If they were, Cindy might ask for (or Bobby might offer) evidence of such life.  If that evidence is absent, both would wisely withhold their judgement on the matter until such evidence was found.


Kids and adults are especially susceptible to this fallacy when they want to believe something is true.  If an idea gives someone deep emotional satisfaction, their inclination to seek out evidence to the contrary might be not be very strong.  This will bring us to next week’s topic- confirmation bias.


Thanks for reading.