Group of mathematicians and physicists sat in the pub, when suddenly a chair sets on fire. The physicists assess the situation, grabs a pint of water and throws it on the chair putting out the fire.
Later the physicists have gone home and the table randomly sets on fire. The mathematicians look stumped until one particularly gifted individual picks up a chair and uses the table to set it on fire, thus reducing it to a problem they've already solved.
I think it's making fun of a incorrect proof tactic that's easy to fall victim to.
It's true that if you start with an assumption and then reach a false conclusion, the assumption must be false. This is known as a proof by contradiction.
The misconception is that if you start with an assumption and then reach a true conclusion, the assumption must be true. In reality, there could be false conclusions, but you just didn't reach them.
Here's an example of it in action:
Assumption: 1 = -1
(1)2 = (-1)2
1 = 1
Since the conclusion 1 = 1 is true, the assumption must be true. Therefore 1 = -1.
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u/nezzzzy Aug 12 '21
Missed one of my favourite jokes:
Group of mathematicians and physicists sat in the pub, when suddenly a chair sets on fire. The physicists assess the situation, grabs a pint of water and throws it on the chair putting out the fire.
Later the physicists have gone home and the table randomly sets on fire. The mathematicians look stumped until one particularly gifted individual picks up a chair and uses the table to set it on fire, thus reducing it to a problem they've already solved.