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Comment by jjgreen | Hacker News Reader

A physicist, walking home at night, spots a mathematician colleague under a street lamp staring at the ground, "something wrong?" he asks; "I've dropped my keys" he replies, "whereabouts?" asks the physicist, keen to help. "Over there" says the mathematician pointing; "So why don't you look over there?" retorts the physicist, "the light is better here" says the mathematician.

Disclosure, I'm a mathematician.

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Another mathematician joke:

Interviewer -- "Consider a situation where you are in your office and there is a fire outside in the hall. There is a fire escape outside your window but you can't reach it because the window is stuck. However, there is a hammer on the table. What do you do?"

Physicist -- "I use the hammer to break the window, allowing me to get out to the fire escape."

Interviewer -- "Now consider the same situation except that the hammer is on the floor. What do you do?"

Mathematician -- "I move the hammer from the floor to the table, thereby reducing it to the previously solved problem."

Physics faculty wants to buy a new expensive research machine. University rector is furious at all this spending and tries to talk some sense into them: "Why aren't you more like the mathematicians, they just need a paper a pencil and an eraser. Or like the philosophers, they just need a paper and pencil"

Or one more related to this article: Mathematicians waste time designing the topology of coats for people with 3 arms. Physicists find people like that.

Oh and my favorite: Mathematician's son goes to school for the first time. The teacher asks: "Who knows how much is 1+2?", the son stands up and says "I don't know how much it is but I do know that it's the same as 2+1 as addition is commutative in the monoid of natural numbers"

I had a lecturer (for a fairly advanced set theory course) who said he told his young son, when teaching him to count, that he, as a set the theorist, ‘doesn’t do finite’. I guess when his son got to school 1+2 might have been ‘the successor of 2’, but anything else would have been ‘less than omega’.

Software developer: It is more important to find out how the keys were dropped in the first place. And after I do that it will be more efficient to just generate new keys.

Disclosure, I'm a software developer

Write a unit test to prevent future key droppings.

Now I didn’t drop them but forgot to even bring them..

Just execute `make building` again and you should get new keys generated.

Right. Just regenerate the keys and the house, then just delete the unneeded house. Storage is cheap.

(The actual unit test merely confirms that dropping the keys in one highly specific way is now impossible. The keys cannot fall from between your fingers because the code now mandates that you wear mittens)

When the regression is handed off to QA, they find that it's still possible to drop keys when: the keys weigh 100 tons, there are thousands of keys, there is no keyring, the keys are actually marbles, or the keys are covered in oil. They also find that when no keys are present initially, one blank key spontaneously appears out of thin air.

When the new anti-key-dropping code ships to users, they find they can no longer put down any singular held objects.

The universe blue screens cause those keys were never supposed to be dropped

I think the typical software solution is to make hundreds of copies of your keys and stash them everywhere you might need them in advance.

Denormalization.

This is actually a variant on a very old joke from Persia originally told about Mullah Nasreddin rather than mathematicians[1]

[1] https://en.wikipedia.org/wiki/Nasreddin#cite_ref-32

True, but Nasreddin was not from Persia but from Asia Minor during Seljuk rule.

I think the person you were replying to was saying that the joke about Nasreddin was from Persia, not that Nasreddin was from Persia. And, they cite that joke to a Wikipedia article, which in turn cites it to a blog post, which quotes it from a book which claims to be translated from Persia. So the attribution of (at least that specific instance of) the joke to Persia is correct.

Also, it is unclear if Nasreddin ever actually existed, or if he is purely legendary. Turkish folklore claims he lived in Asia Minor during the Seljuks, but Uzbek folklore claims he was an Uzbek who lived in Uzbekistan. Some Azerbaijani scholars have identified him with the 13th century Persian polymath Nasir al-Din al-Tusi.

Physicist: but that doesn't get you any closer to a solution.

Mathematician: not yet, but if I wait here long enough someone will come by and drop their keys, which will then be retrieved, proving the possibility of retrieving lost keys when light conditions are optimal.

Physicist drops keys.

Mathematician: Eureka!

I guess it should really be proving the general proposition that dropped keys are discoverable.

Great, it's been proven. Should we go pick up our keys now or just move onto another math problem?

I need to publish first.

on edit: can I stay at your house for a bit while waiting for publication?

Not related, but there is a quote by someone regarding statistics which goes like:

"Don't use statistics like how a drunkard uses a lamp-post, for support rather than for illumination".

An engineer, a physicist, and a mathematician are on a train from London to Edinburg. It will be the first time any of them have been to Scotland.

In Scotland the train passes a field and there is a single sheep standing in that field. The sheep is black.

The engineer says, "Look! The sheep in Scotland are black!".

The physicist sighs, shakes his head, and says, "No...at least one sheep in Scotland is black".

The mathematician sighs, shakes his head, and rolls his eyes, and says, "No...at least one sheep in Scotland is black on at least one side at least some of the time".

Buddhist would say - There is just changing patterns, sensations and thoughts that create an illusion that there is a sheep outside and seperate you watching it. In reality there is just emptiness.

I don’t get it.

Disclosure: I’m a software developer

Non-software-developer humans often use things called "lamps" to illuminate spaces at night. Unfortunately, illumination inhibits effective nighttime coding.

> humans often use things called "lamps" to illuminate spaces at night

I call those "monitors."

That's a bug. We should fix that.

Mathematicians like to develop new math right at the boundary of what is known. Physicists don’t have that luxury because they have to describe/model/build/etc things that correlate to what is actually going on in the world.

The mathematician of this joke would scan the edge of the light, finding nothing. Then he would keep lighting little lanterns at the perimeter to make the lighted area larger until finally his keys were within sight.

The physicist in this joke would presumably root around in the dark where she thinks her keys actually were. Upon finding them through brute force and luck, she might think “wow maybe one day this place will be illuminated so I can tell wtf I just did”

The idea is that often a breakthrough in mathematics isn't achieved by tackling a problem directly, but converting it to a simpler problem, then solving that one.

Disclosure: I'm a software developer.

Funny joke. Reminded me of this xkcd comic but with the roles reversed.

https://xkcd.com/435

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