system
Given the following post, respond as if you're commenting on Reddit:
human
Real life applications of paradoxes?

I'm not a philosophy major, but I love the subject and thus I have subscribed to this wonderful subreddit.
 
One of my favorite concepts to think about are paradoxes. I'm particular to the Paradox of the Heap because I find it very applicable to many real life situations.
 
I'd like to learn about more paradoxes that can be applied in practical arguments, from politics to otherwise.

  
So I suppose the tl;dr of this post is to ask:
 
What's your favorite paradox to reference in real life situations?
gpt
I once heard a conference talk in which someone explained the following "paradox" concerning expert consensus:

Three experts are brought in to determine what should be done about a situation where a well has been potentially poisoned.  Each is asked the following two questions: 1) If the toxicity level is above X%, should we then close the well? and 2) Is the toxicity level above X%?  The three experts answer as follows...

Expert 1: 1) Yes  2) No

Expert 2: 1) Yes  2) Yes

Expert 3: 1) No   2) Yes

If we take the majority decision on each question, it seems that the expert "consensus" is that we *should* close the well if there is X% toxicity, and that there *is* X% toxicity.  Therefore, we should close the well.

*HOWEVER*, if we don't take the most popular expert opinions on each of the two questions, but instead ask each expert if the well should be closed, it would seem that the majority (on pain of violating *modus ponens*) would say that we should *NOT* close the well.  

Two seemingly equally respectable approaches (with prima facie innocuous differences) to assessing expert opinion yield opposite results.