“How did the person who invented the first clock know what time it was?”

People set their clocks and watches to other ones, leading to a joke:
 
“How did the person who invented the first clock know what time it was?”
 
“How did the person who invented the first clock know what time to set it to?” was cited on Twitter on January 3, 2011, and the joke went viral in 2015.  The website I Can Has Cheezburger? illustrated the saying.
   
 
Twitter
prune juice
‏@KariukiMachine
#randomthoughts how did the person who invented the first clock know what time to set it to? Can we also say he invented time?
11:59 PM - 3 Jan 2011
 
Twitter
CairaNaomiMurray
‏@CairaMurray
How did the man who invented the first clock know what time it is. MIND=BLOWN.
6:24 PM - 9 Apr 2012
 
Twitter
Alex
‏@WeSeizeTheDay
how did the guy who invented the first clock know what time it was?
5:45 AM - 3 Jan 2013
 
Twitter
DaBear
‏@astutenewf
13: How did the person who invented the first clock know what time it was?
Me: *head blows up*
4:55 AM - 29 Sep 2014
 
reddit
How did the person who invented the first clock know what time it was? (self.Showerthoughts)
November 12, 2014 by lilitaly92
 
AskReddit
How did the person who invented the first clock know what time it was? (self.AskReddit)
March 15, 2015 by dobond
   
EyeVey thoughts
March 21, 2015 by EyeVey
How did the person who invented the first clock know what time it was?