coffee-and-theorems
Explanation
The Joke
A mathematician shares a well-known joke within the math community: "A mathematician is a machine that turns coffee into theorems." This is a real and famous quote widely attributed to the Hungarian mathematician Paul Erdos (though sometimes credited to Alfred Renyi). The other person says she does not get it.
The mathematician then "explains" the joke by saying, "The joke is that it's actually amphetamines." The other person responds with a drawn-out "Ahhhhhh" of sudden understanding, as if this darker explanation makes the joke click. The implication is that mathematicians are not merely fueled by coffee but by amphetamines (stimulant drugs), and that this is the hidden truth behind their prodigious output.
The Humor
The humor operates on multiple levels. First, there is the meta-comedy of "explaining" a joke by making it darker and more disturbing rather than actually clarifying it. Second, there is a real historical reference: Paul Erdos, who is associated with the original coffee-into-theorems quote, was famously known to use amphetamines to fuel his extraordinarily prolific mathematical output. So the "joke" the mathematician is telling is actually a thinly veiled confession about drug use in academia. The fact that the non-mathematician only understands the joke once it becomes about drugs -- rather than about the more innocent idea of coffee-fueled productivity -- adds another layer of absurdity.
References
The quote "A mathematician is a machine that turns coffee into theorems" is most commonly attributed to either Paul Erdos or Alfred Renyi. Paul Erdos (1913-1996) was one of the most prolific mathematicians in history, publishing around 1,500 papers. He was also well-known for his use of amphetamines, which he claimed helped him work productively. When a friend bet him he could not stop taking them for a month, Erdos won the bet but complained that mathematics had been set back by a month because he could not work without them.