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If Richard Feynman applied for a job at Microsoft... (sellsbrothers.com)
189 points by Indyan 2396 days ago | hide | past | web | 77 comments | favorite

Reminds me of the bit in Cryptonomicon where Lawrence Waterhouse takes an intelligence test for the navy:

"They gave him an intelligence test. The first question on the math part had to do with boats on a river: Port Smith is 100 miles upstream of Port Jones. The river flows at 5 miles per hour. The boat goes through water at 10 miles per hour. How long does it take to go from Port Smith to Port Jones? How long to come back?

Lawrence immediately saw that it was a trick question. You would have to be some kind of idiot to make the facile assumption that the current would add or subtract 5 miles per hour to or from the speed of the boat. Clearly, 5 miles per hour was nothing more than the average speed. The current would be faster in the middle of the river and slower at the banks. More complicated variations could be expected at bends in the river. Basically it was a question of hydrodynamics, which could be tackled using certain well-known systems of differential equations. Lawrence dove into the problem, rapidly (or so he thought) covering both sides of ten sheets of paper with calculations. Along the way, he realized that one of his assumptions, in combination with the simplified Navier-Stokes equations, had led him into an exploration of a particularly interesting family of partial differential equations. Before he knew it, he had proved a new theorem. If that didn't prove his intelligence, what would?

Then the time bell rang and the papers were collected. Lawrence managed to hang onto his scratch paper. He took it back to his dorm, typed it up, and mailed it to one of the more approachable math professors at Princeton, who promptly arranged for it to be published in a Parisian mathematics journal.

Lawrence received two free, freshly printed copies of the journal a few months later, in San Diego, California, during mail call on board a large ship called the U.S.S. Nevada. The ship had a band, and the Navy had given Lawrence the job of playing the glockenspiel in it, because their testing procedures had proven that he was not intelligent enough to do anything else."

Similarly, though not as funny, from "The Legend of John Von Neumann" - http://stepanov.lk.net/mnemo/legende.html

'Then there is the famous fly puzzle. Two bicyclists start twenty miles apart and head toward each other, each going at a steady rate of 10 m.p.h. At the same time a fly that travels at a steady 15 m.p.h. starts from the front wheel of the southbound bicycle and flies to the front wheel of the northbound one, then turns around and flies to the front wheel of the southbound one again, and continues in this manner till he is crushed between the two front wheels. Question: what total distance did the fly cover ? The slow way to find the answer is to calculate what distance the fly covers on the first, northbound, leg of the trip, then on the second, southbound, leg, then on the third, etc., etc., and, finally, to sum the infinite series so obtained. The quick way is to observe that the bicycles meet exactly one hour after their start, so that the fly had just an hour for his travels; the answer must therefore be 15 miles. When the question was put to von Neumann, he solved it in an instant, and thereby disappointed the questioner: "Oh, you must have heard the trick before!" "What trick?" asked von Neumann; "all I did was sum the infinite series." '

all I did was sum the infinite series

This is meant to sound very difficult (and might be, if you majored in journalism), but summing infinite geometric series is easy enough to do in your head if you're facile with fractions: (first_term) / (1 - step_multiplier).

Observe that, of the combined velocity of the fly and the bike approaching him, the fly always makes up 60%. That makes math easier since it eliminates division and time from the problem entirely.

On the first trip, the fly travels 12 miles and the bike approaching him travels 8 miles. There are now 4 (20 - 2 * 8) miles between the bikes.

On the second trip, the fly travels .6 * 4 = 2.4 miles and the bike approaching him travels 1.4 * 4 = 1.6 miles. There are now 0.8 miles between the bikes.

The part where people who are really good with math distinguish themselves from people who are not is realizing quickly that the problem they are looking at, with flies and bikes, quickly decomposes into "sum the series that starts 12, 2.4, etc".

12 / (1 - 0.2) = 12 * 5 / 4 = 15 miles total fly travel.

You can do it a little more formally if you want to verify the intuition that each step takes 1/5th the time (covers 1/5th the distance) of the previous step. (My intuition says "In the time that it takes the fly to go 5 units, the two bikes will chew up 4 units of that distance, so he is only left with 1 unit to travel the next time.")

I don't think it's about difficulty per se but the number of computations required. If 25 miles were covered by the fly and a bicycle, the fly covers 15 making it 60% (first calculation). Thus for 20 miles, the fly covers 12, bicycle 8 (second calculation). 20-16 or 4 miles are remaining of which the fly covers 2.4 (third computation). 2.4 is one-fifth of 12 (fifth computation). 12 / 0.8 => 12 * 5/4 = 15 (sixth computation). This route will always be slower because it requires more computations.

Where intuition really comes in is finding the right hill to climb - http://en.wikipedia.org/wiki/Hill_climbing

There is another "trick" solution : Let's denote a point when the fly turns around to be a step. Then just notice, from any one step the next, the fly travels exactly 1.5x the distance of any of the bicycles, since it goes 15mph versus the bicyclye's 10mph. This holds at each step, so is true of the total distance traveled as well. But alltogether, one bicycle will travel exactly half of the 20miles, so 10miles. So the fly will travel 15miles.

If you like this kind of puzzle, you might enjoy "Thinking Physics" by Lewis Carroll Epstein. This one is right on page 10 of the 3rd edition.

I wish that there was a universal credits system on the internet, and that I could purchase books by the page.

Just use Google books (or something similar). It allows you to view certain pages. It's not optimal, though.

It's rather arguable that Waterhouse's inability to recognize that the question scenario was a deliberate simplification justifies his naval assignment. Because while he's clearly a brilliant mathematician in the story, he's really too damn dim about everything else to trust with much practical responsibility...

unfortunately, there is some practical truth in this Navy evaluation - Lawrence would definitely failed (ie. wouldn't complete them on-time and according to SOP) most of the assignments in the Navy or military in general.

That would simply be an indication that he was not suited for applying to the Navy. I find that many people who suck and fail at something may truly suck at whatever it is, but they're actually quite awesome at something else. The sad thing is that most people don't know how to find their path and even fewer people know how to set people on the right path where they can achieve their potential.

Don't worry - he ends up doing the right thing in the end. Read the book, though, it's full of good stuff like that.

For those who think this doesn't sound at least a little bit like Feynman, I highly recommend this video: http://www.youtube.com/watch?v=wMFPe-DwULM

This video reminds me of an essay from Eliezer Yudkowsky¹. Feynman was basically forced to give a mysterious answer to a mysterious question. He did so, but not before talking about semantic stop-signs², how "magnetic force" could be one, and why it shouldn't be. Brilliant.

[1]: http://lesswrong.com/lw/iu/mysterious_answers_to_mysterious_... [2]: http://wiki.lesswrong.com/wiki/Semantic_stopsign

His chess analogy is the best thing of his you can find on youtube, I think: http://www.youtube.com/watch?v=o1dgrvlWML4

This comes up every now and then on social websites and every time I completely disagree that it reads like Feynman or that Feynman would react that way.

Really? Have you read the piece (I believe it's in Surely You're Joking...) where Feynman gets evaluated by an Army psychologist? It reads very similarly to this.

He basically said those things in an interview once. So while he might not react that way when looking for a job it really just depends on how much he wanted the job.

it really just depends on how much he wanted the job

I disagree. Feynman was famous for speaking his mind regardless of the context (Bohr insisted on Feynman's presence at critical points during the Manhattan project for exactly this reason, in fact -- everybody else was too inhibited around Bohr to speak up).

Feynman might have kicked himself afterwards, but wanting a job wouldn't have prevented him from pointing out an interviewer's errors.

There is a huge gap between speaking truth to power and being snippy to make yourself feel better. As a ridiculously intelligent and anti authoritarian friend put it. "You don't walk around barefoot on the first day of a new job, you need to break people in."

PS: And yes, he would eventually walk around the office / data centers without footwear.

You don't walk around barefoot on the first day of a new job, you need to break people in

I agree. And I'm sure Feynman would have agreed... until he got excited about something, at which point he would have completely forgotten.

I do to. There's nothing to it.

What things? The manhole stuff? Do you have a link?

Yea the manhole stuff was on google video, I think it may have been:


Or something linked from there.

PS: "Tuva or Bust"

Edit: Sorry, I am having trouble finding it. There are several interviews that video is based on but they don't show the whole video.

"The Pleasure Of Finding Things Out"?

From the BBC Horizon program in 1981.


Oh? Do you have a source?

His name has become a kind of strawman.

A ficitonal interloculor to whom one attributes poor arguments in order to easily refute them?

No. My usage is perhaps a new use of the word, but it fits with the metaphor of a man of straw.

Is there another word already in existence, that describes what I wanted to say? "A ficitonal interloculor to whom one attributes one's own's arguments in order to make them sound more profound."

"Oscar Wilde".

I'm not sure Feynman would respond this way, but he's one of my personal heroes. If you haven't read "Surely You're Joking, Mr. Feynman" please do yourself a favor and pick up a copy immediately.

The follow up "What Do You Care What Other People Think?" is also a great read and incredibly heartbreaking.

And the next logical step is to read the book that has his compiled letters. Great stuff.

And of course Mr. Feynman Goes To Washington . I think the ultimate point is that all of his books are awesome. I even liked some of the science stuff. ;-)

The first few chapters of his Lectures on Physics are suprisingly readable as popular science. Later on it gets more hard-science-y.

I'd say the next logical step is to read James Gleick's biography "Genius", which gives a slightly more well-rounded view.

If you rename this 'If Sheldon Cooper applied for a job at Microsoft' this works beautifully :)

Or Paul Dirac. He had a very literal mind.

(I just read Graham Farmelo's bio of Dirac, and I highly recommend it for those who are fascinated by genius physicists like I am)

I just bought the book after I found out while reading parts at the store that I lived 2 buildings over from his house in Florida (Tallahassee) while in college at FSU.

Dirac is a legend there not only does he have a library named after him there, the National High Magnetic Field Laboratory at FSU is on Paul Dirac drive ;p

Feynman or not, it's entertaining to anyone who has waded through several hours of contrived interview questions that supposedly relate to programming ability, and that always have a "right" answer.

I had a four hour long interview for a systems programming/administration position where plebeian admins were allowed to grill me for about 25% of the time, asking me to whiteboard viable algorithms for cute little problems they concocted. All of my solutions would have functioned flawlessly and would have met all of the stated requirements, but they didn't involve the same thought processes that the interviewers had used. I "failed" but in the end, I won. I would not have fit in there anyway.

As much as they're interviewing you, you're interviewing them as well. If you're a smart guy, you hopefully have enough prospects that if you don't want to work with pedantic nitwits, you don't have to.

I was interviewing them as well, but I was 4 months unemployed with a disabled wife that couldn't work but whose disability claim was in limbo. I might have actually taken the job had I been offered one, sadly.

Fortunately, all's well that ends well. An old headhunter I'd used in the past tossed my info along (for FREE!) to my current boss. After talking to me on the phone, he gave me the old "We don't have a position open, but I'll call you if something opens up" line. I wrote it off, but he worked to get a position opened up for me and I'm genuinely doing what I love to do for a living these days. It involves Information Security, physical security/surveillance and general-purpose IT work (Sysadmin, programming and networking). I'm basically in geek heaven. It's also 6 miles from home, giving me the perfect excuse to ride my bike to work every day, rain or shine.

Hang on - in the US the candidate pays the headhunter?

No. In my case, I worked for the headhunter as a consultant to a company that eventually hired me. The agency takes a percentage of the first year's salary in many of these situations. That said, I had really good luck with this agency and the recruiter himself personally. Many are scum-bags. If you find a good one, keep 'em on speed dial. You never know when you or a friend will want some help finding work.

Many interviewers don't realize it.

I had a similar experience, asked to design a sudoku solver.

Coming from an AI background, I coded up an algorithm for state-space search.

They were expecting me to approach it as a person would, reasoning about how you rule out certain numbers (the constraint propagation), which is a second-order consideration for a game the size of sudoku.

I felt pretty smug when Peter Norvig shortly thereafter put up a blog post that essentially mirrored my solution.

Were they duly impressed or was it "wrong"?

As far as I know Norvig's solver has constraint propagation (maybe it didn't have it in the first version though).

Nothing really clever though - he only applies the two most basic sudoku strategies:

   If a square has only one possible value, eliminate it from the square's peers.
   If a unit has only one possible place for a value, then put the value there.
And then he notes that those simple strategies combined with search yields very reasonable run times.

Actually, for 9x9 Sudoku doing any more advanced propagation is pointless, since it will slow down the time to find the solution (assuming a reasonably fast search process). If one wants to solve 9x9 Sudokus without search, full propagation combined with shaving (hypothetical reasoning: if I assigned this square this value, woould it lead to an inconsistency) suffices as far as is known currently (no proof, just experiments, http://www.4c.ucc.ie/~hsimonis/sudoku.pdf).

For 16x16, it is more of a toss-up if one should use more advanced propagation. The solve-times are still so low though, that it doesn't really matter (tens of milliseconds). For 25x25 it starts to get interesting. In my experience, full propagation on lines, rows, and regions is needed, but more than that slows it down. Without a good heuristic (some learning process, prefferably coupled with randomized restarts), the solve-time easily goes up into hours. Wih a good heuristic, minutes seems to be a reasonable time-span to hope for.

It might not be that clever, but it is able to considerably reduce the running time of the algorithm (even if the speedup in a 9x9 puzzle is not perceived).

In fact, if you ask people not from a CS background to explain the steps they would take to solve a puzzle, they probably wouldn't be able to think of a DFS, but they would state that they should rule out from each cell the numbers already present in its respective column, line and block. And for a Sudoku solver I don't think you really need more constraint propagation than that.

Anyway, I think you approached the problem the right away, I just think that you were so close to succeed in that test and it wasn't something that difficult to add to your solution.

EDIT: wrote the above before your edit. It's still appropriate though.

Right - my point was that they were expecting the naive approach, starting from human heuristics and building up.

They were confused when I took a more disciplined approach and provided a solution that is robust to simple CP methods.

Of anyone I've read or seen (in person or from videos), Feynman has the best fundamental grasp of meta-knowledge. By meta-knowledge, for lack of a better term, I mean understanding what it means to know something.

mhartl has already posted this excellent video: http://www.youtube.com/watch?v=wMFPe-DwULM, where he explains what the word "why" means in scientific inquiry. When we answer a "why" question, we don't really explain a concept in its entirety. At best, we're able to remove a layer of skin off the onion, but no one has ever really reached the center. I suppose science at it's heart is really just the elucidation of intermediate cause and effect scenarios.

For the question "why did the ball fall?", "Jimmy dropped it" is a perfectly valid answer. So is "Jimmy's motor neurons passed an action potential threshold, causing the muscles in his wrist to contract". So is "the ball moved along the curvature of space caused by the earth".

How far do we go?

"meta-knowledge" is called epistemology. http://en.wikipedia.org/wiki/Epistemology

The best part : If we are just considering the round ones, then they are round by definition. That statement is a tautology.

Feynman wouldn't have said that particular line, was my own reaction.

To be fair, MS hasn't used this sort of "puzzle based" interviewing system for years.

Uhh. I had one such question asked by the MSFT interviewer 2 weeks or so ago...

Anyone can still ask you whatever questions they want during an interview, but as a matter of policy and culture MS moved away from puzzles years ago. Notwithstanding there may still be hold outs.

That's very surprising. I was pretty sure we had stopped asking those questions a long time.

What type of position? Software engineering or something else?

What was the question?

That Feynman is not very Feynman-like.

I think I've seen this before, except Feynman was going on about how circles aren't the only constant width shapes:


Someone used this principle to create this strange bicycle: http://www.china.org.cn/china/photos/2009-05/07/content_1773...

To be a touch prosaic, is it simplest to cover a round hole with a round cover? No, Round holes are drilled. Covers for them can be simply cut squarely from stock. Why have a geometric match? Either way provision has usually to be made for covers to he bolted and locked down even if they are resting on a flange.

I liked the surprise ending.

Me too. But on second thought, he didn't come across as a marketing type. Not to me, at least. More like a R&D guru.

I read it as "Microsoft is too incompetent to put him in the right department", but maybe that wasn't the intent.

Heard this one before, and it made me think of the barometer problem:


Holy crap, anyone else notice the number of totally obvious paid links on that site? What not to do...

Of course TRWTF is that he's applying for a job at Microsoft.

Well its not real, but also it wouldn't be that crazy I don't think. I mean it is weird they would interview him, but he was a computer and then later actually worked on computers (the machines) http://www.longnow.org/essays/richard-feynman-connection-mac...

Wonderful essay. I especially love this:

I remember a conversation we had a year or so before his death, walking in the hills above Pasadena. We were exploring an unfamiliar trail and Richard, recovering from a major operation for the cancer, was walking more slowly than usual. He was telling a long and funny story about how he had been reading up on his disease and surprising his doctors by predicting their diagnosis and his chances of survival. I was hearing for the first time how far his cancer had progressed, so the jokes did not seem so funny. He must have noticed my mood, because he suddenly stopped the story and asked, "Hey, what's the matter?"

I hesitated. "I'm sad because you're going to die."

"Yeah," he sighed, "that bugs me sometimes too. But not so much as you think." And after a few more steps, "When you get as old as I am, you start to realize that you've told most of the good stuff you know to other people anyway."

We walked along in silence for a few minutes. Then we came to a place where another trail crossed and Richard stopped to look around at the surroundings. Suddenly a grin lit up his face. "Hey," he said, all trace of sadness forgotten, "I bet I can show you a better way home."

And so he did.

Just finished reading "Surely you're joking, Mr. Feynman" - one of the best reads ever!

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