“A guy walks into a bar…” is a typical form of what has been called the “bar joke.” One “Descartes before the horse” (the cart before the horse) pun combines two jokes:
 
1. The horse joke: “A horse walks into a bar and the barman says, ‘Why the long face?’”
 
2. The Descartes joke: “René Descartes walks into a bar, see. He orders a glass of wine and drinks it. The bartender says, ‘Would you like another?’ Descartes replies, ‘I think not.’ And he disappears.”
     
     
Reddit—Jokes
Posted by u/cattailmatt March 12, 2015
The driest, most esoteric joke I know.
A horse walks into a bar. The bartender asks the horse if it’s an alcoholic considering all the bars he frequents, to which the horse replies I don’t think I am” “I think not!” POOF! The horse disappears.
This is the point in time when all the philosophy students in the audience begin to giggle, as they are familiar with the philosophical proposition of Cogito ergo sum, or I think, therefore, I am.
But to explain the concept aforehand would be putting Descartes before the horse.
COMMENTS
Weenus_gone_wild
Descartes is the originator of the phrase “I think, therefore I am.”
The horse said “I don’t think I am”, meaning he no longer thought he was, therefore he wasn’t. Hence why he disappeared.
Explaining the concept first is putting Descartes before the horse, which is what I just did. It is a pun on “putting the cart before the horse”.
     
Reddit—Jokes   
Posted by u/poppawheeelie March 31, 2016
A horse walked into a bar. The bartender said “hey.” The horse said “you read my mind.” Descartes was behind him and the Bartender said “hey” to him.
Descartes said “I think not” and disappeared. This joke works best if you don’t put Descartes before the horse.
 
Reddit—Jokes
Posted by u/cogenix October 18, 2016
A horse walks into a bar and orders a pint.
The barkeeper says “you’re in here pretty often. Think you might be an alcoholic?”, to which the horse says “I don’t think I am.”, and vanishes from existence.
See, the joke is about Descartes’ famous philosophy of ‘I think therefor I am”, but to explain that part before the rest of the joke would be to put Descartes before the horse.
 
Reddit—Jokes
Posted by u/SirMuffinIII October 29, 2016
A Horse Walks Into A Bar
A horse walks into a bar and orders a pint. The barkeep says “you’re in here pretty often. Think you might be an alcoholic?”, to which the horse says “I don’t think I am.”, and vanishes from existence.
See, the joke is about Descartes’ famous philosophy of ‘I think therefore, I am”, but to explain that part before the rest of the joke would be to put Descartes before the horse.
   
Reddit—Jokes
Posted by u/aedroogo January 4, 2017
A horse walks into a bar…
A horse walks into a bar. The bartender asks the horse if it’s an alcoholic, to which the horse replies, “I don’t think I am.” POOF! The horse disappears.
This is the point in time when any philosophy students in the audience begin to giggle, as they are familiar with the philosophical proposition of cogito ergo sum, or roughly, “I think, therefore I am.”
But to explain that concept beforehand would be putting Descartes before the horse.
   
Twitter
Elaine Hamilton
@chimerasame
A horse walks into a bar. The bartender asks, “Why the long face?”
Rene Descartes walks into a bar. The bartender asks if he wants a drink. He says “I think not!” and disappears.
Always tell these two jokes in this order; or else you would be putting Descartes before the horse.
12:36 PM · Dec 5, 2017·Twitter Web Client
   
Twitter
wait… we might be cuzins
@mightysmith
A horse walks into a bar and orders a pint. The barkeep says “you’re in here pretty often. Think you might be an alcoholic?”, to which the horse says “I don’t think I am.”, & vanishes from existence. I could explain the joke but that would be putting Descartes before the horse.
2:42 PM · Jan 25, 2018·Twitter Web Client
 
Reddit—Jokes
Posted by u/Ferdtuff October 18, 2018
A horse walks into a bar and orders a beer. The barkeeper says “you’re in here pretty often. Think you might be an alcoholic?”, to which the horse says “I don’t think I am.”, and vanishes from existence.
See, the joke is about Descartes’ famous philosophy of ‘I think therefore I am”, but to explain that part before the rest of the joke would be to put Descartes before the horse.
   
Reddit—Dadjokes
Posted by u/arayakim September 16, 2019
A horse goes into a bar and orders a pint.
The bartender says “You know, you’re in here pretty often. Do you think you might be an alcoholic?”
The horse says “I don’t think I am…” and promptly vanishes from existence.
See, this was a joke about Descartes’ famous line from philosophy, “I think, therefore I am.”
But if I had explained that before the rest of the joke, it would have been putting Descartes before the horse.
 
Reddit—Jokes
Posted by u/Anthonybrose November 23, 2019
A horse goes into a bar and orders a pint.
The bartender says: You know, you are in here pretty often. Do you think you might be an alcoholic?
The horse says: I don’t think I am… and promptly vanishes from existence.
You see this is a joke about Decartes’ famous line from philosophy “I think, therefore I am”
But if I had explained that before the rest of the joke, it would have been putting Descartes before the horse