What would Feynman do? (2011)(blogs.msdn.com)
blogs.msdn.com
What would Feynman do? (2011)
http://blogs.msdn.com/b/ericlippert/archive/2011/02/14/what-would-feynman-do.aspx
12 comments
True, but I think he may have had some fun with the interviewer, and thought it may be worth taking him down a peg or two.
Feynman was amazingly good at giving serious smackdowns in a convivial way. He would be cheerful, accepting and charming while creating a logical argument that was almost always faultless.
He had some negatives, but I think he was one of the most amazing people to have ever lived. I encourage everyone out there to read and watch his publications and lectures. From grad student til death, he forced people to rethink the hardest and most important problems around, and he had fun doing it.
He was also a prankster, a lock-picker and safe-cracker, and apparently a pretty good musician.
</hero_worship>
Feynman was amazingly good at giving serious smackdowns in a convivial way. He would be cheerful, accepting and charming while creating a logical argument that was almost always faultless.
He had some negatives, but I think he was one of the most amazing people to have ever lived. I encourage everyone out there to read and watch his publications and lectures. From grad student til death, he forced people to rethink the hardest and most important problems around, and he had fun doing it.
He was also a prankster, a lock-picker and safe-cracker, and apparently a pretty good musician.
</hero_worship>
I would turn one switch on, walk into the other room and see which light turned on, then walk back into the first room, flip another switch, and go back and see which light was turned on.
When inevitably someone came to my desk and asked why I was violating procedure, I would say that my way was simpler and more efficient than the alternatives, and therefore saves the company time and money. I would then offer to change my behavior if they had a better solution to the problem.
This is a management problem, not a logic problem.
When inevitably someone came to my desk and asked why I was violating procedure, I would say that my way was simpler and more efficient than the alternatives, and therefore saves the company time and money. I would then offer to change my behavior if they had a better solution to the problem.
This is a management problem, not a logic problem.
As much as yawaramin's comment about him poking fun at programmers is probably correct, Feynman wasn't a total stranger to computer science:
> Feynman worked out the program for computing Hopfield's network on the Connection Machine in some detail. The part that he was proudest of was the subroutine for computing logarithms. I mention it here not only because it is a clever algorithm, but also because it is a specific contribution Richard made to the mainstream of computer science. He invented it at Los Alamos.
http://longnow.org/essays/richard-feynman-connection-machine...
> Feynman worked out the program for computing Hopfield's network on the Connection Machine in some detail. The part that he was proudest of was the subroutine for computing logarithms. I mention it here not only because it is a clever algorithm, but also because it is a specific contribution Richard made to the mainstream of computer science. He invented it at Los Alamos.
http://longnow.org/essays/richard-feynman-connection-machine...
If you read his books (which he dictates) he also appears to have come up with a basic concept of parallelism and pipelining which he managed to do on punchcard machines of the time by mixing up groups of different computations in the punchchard stacks based on dependent variables in the computations they were doing.
Here's another telling of the story
http://www.mphpa.org/classic/HISTORY/H-06c18.htm
The new IBM punched-card machines were devoted to calculations to simulate implosion, and Metropolis and Feynman organized a race between them and the hand-computing group. "We set up a room with girls in it. Each one had a Marchant. But one was the multiplier, and another was the adder, and this one cubed, and all she did was cube this number and send it to the next one," said Feynmann. For one day, the hand computers kept up: "The only difference was that the IBM machines didn't get tired and could work three shifts. But the girls got tired after a while."
Feynmann worked out a technique to run several calculations in parallel on the punched-card machines that reduced the time required. "The problems consisted of a bunch of cards that had to go through a cycle. First add, then multiply, and so it went through the cycle of machines in this room - slowly - as it went around and around. So we figured a way to put a different colored set of cards through a cycle too, but out of phase. We'd do two or three problems at a time," explained Feynman. Three months were required for the first calculation, and Feynman's technique reduced it to two or three weeks.
Here's another telling of the story
http://www.mphpa.org/classic/HISTORY/H-06c18.htm
The new IBM punched-card machines were devoted to calculations to simulate implosion, and Metropolis and Feynman organized a race between them and the hand-computing group. "We set up a room with girls in it. Each one had a Marchant. But one was the multiplier, and another was the adder, and this one cubed, and all she did was cube this number and send it to the next one," said Feynmann. For one day, the hand computers kept up: "The only difference was that the IBM machines didn't get tired and could work three shifts. But the girls got tired after a while."
Feynmann worked out a technique to run several calculations in parallel on the punched-card machines that reduced the time required. "The problems consisted of a bunch of cards that had to go through a cycle. First add, then multiply, and so it went through the cycle of machines in this room - slowly - as it went around and around. So we figured a way to put a different colored set of cards through a cycle too, but out of phase. We'd do two or three problems at a time," explained Feynman. Three months were required for the first calculation, and Feynman's technique reduced it to two or three weeks.
I'm surprised the alleged Niels Bohr baromoter story did not show up here yet:
http://www.snopes.com/college/exam/barometer.asp
Feynman loved logical puzzles, and knew lots of them off by heart. What would actually have happened is that the interviewer would have got as far as "there are three light switches..." when Feynman would have interrupted by reciting the correct answer.
No, he wouldn't let her know that he knew it in advance :)
There's another, shorter one, answering the "why are manhole covers round" question: http://www.sellsbrothers.com/posts/details/12395
This one is actually linked to in the article, where the author writes "In that tradition, I present a sequel to Keith Michaels' 2003 exercise in counterfactual reasoning. "
That one was much more difficult to imagine being answered by a Feynman-like persona.
I heard Feynman's thick accent in my head while reading that. Well written.
The great thing about his lectures is hearing high-level physics being explained in the voice of a Brooklyn taxi driver. Always annoyed me that Asimov moderated his accent for public consumption.
You might really enjoy Leonard Susskind: https://www.youtube.com/watch?v=KR3Msi1YeXQ
He's another New Yorker, from the South Bronx, helped start String Theory back in the 60's or 70's. He has lots of stuff online: http://theoreticalminimum.com/
He's another New Yorker, from the South Bronx, helped start String Theory back in the 60's or 70's. He has lots of stuff online: http://theoreticalminimum.com/
I would round up three people and ask them to each stand near the different light and ask them to tell me when their light turned on or off.
You might look at this question as a means to discern whether or not you are a team player.
You might look at this question as a means to discern whether or not you are a team player.
That's precious.
I wonder if interviewers are still asking that question in the era of LED lamps.
In practice, this is the right answer: http://www.zircon.com/products/electrical-breaker-id-pro.htm...
I wonder if interviewers are still asking that question in the era of LED lamps.
In practice, this is the right answer: http://www.zircon.com/products/electrical-breaker-id-pro.htm...
LED lights still get pretty hot, e.g. the big metal blob at the bottom of this one [1] is a heatsink.
[1] http://i.imgur.com/suml2Ei.jpg
[1] http://i.imgur.com/suml2Ei.jpg
Very bright LED lights can get hot, but e.g. the LED bulb in the table-lamp next to me right now (a "40W equivalent" bulb) is still quite cool to the touch, even though it's been turned on all night (fell asleep without turning it off!)...
Ha, ha. Actually Feynman believed that software was a time sink, and would lead you down a rabbit hole of doing busywork solving puzzles that arose from creating levels of abstraction on top of each other.
As it turns out, he was mostly right!
As it turns out, he was mostly right!
"Well, Mr. Frankel, who started this program, began to suffer from the computer disease that anybody who works with computers now knows about. It's a very serious disease and it interferes completely with the work. The trouble with computers is you play with them. They are so wonderful. You have these switches--if it's an even number you do this, if it's an odd number you do that--and pretty soon you can do more and more elaborate things if you are clever enough, on one machine."
Straight from the man himself. Page 79 of [PDF warning] http://buffman.net/ebooks/Richard_P_Feynman-Surely_Youre_Jok...
Straight from the man himself. Page 79 of [PDF warning] http://buffman.net/ebooks/Richard_P_Feynman-Surely_Youre_Jok...
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Wow. This level of anal spelunking for the privilege to work on speeding up excel macros and word auto-completion? No thanks.
I'm no Feynman, but the "what if all three bulbs had been continuously lit for 12 hours previously, and were _all_ hot" objection always occurred to me after hearing the solution to this so-called brain teaser.
In my opinion, this looks like the sort of question originally posed by some pointy-haired type who had been reading too much 90s "Lateral Thinking" style pop lit.
In my opinion, this looks like the sort of question originally posed by some pointy-haired type who had been reading too much 90s "Lateral Thinking" style pop lit.
Fundamentally these types of questions are a tacit admission that the organization in question is incompetent at the task of identifying qualified employees.
Can you imagine hiring a surgeon, or a civil engineer, or, hell, a mechanic or carpenter based on brain-teaser questions? Nope. The interviewee would look at you like you'd grown an extra head, and probably start trying to figure out a way to bring the interview to an early end.
Can you imagine hiring a surgeon, or a civil engineer, or, hell, a mechanic or carpenter based on brain-teaser questions? Nope. The interviewee would look at you like you'd grown an extra head, and probably start trying to figure out a way to bring the interview to an early end.
These sorts of questions are psychological, not logical. They require the person being asked to make the same assumptions about the ambiguities and open questions as the person asking.
As such, they have nothing to do with reasoning ability. The "correct" answer is often completely wrong, like the claim that access hole covers are round "so they don't fall in", which misses the important point entirely. A circle is the minimum size cover that can't be dropped into the hole it covers. Make the cover twice as big as the hole and you have no problem. It is only under the common but special case of resource constraints that round covers are compelling.
There was also that ridiculous one about "how do you put an elephant in a refrigerator" where the "correct" answer depended on not knowing the difference between the definite and indefinite articles. The next question was "How do you put a giraffe in a refrigerator" and the "correct" answer was "You open the refrigerator, take out the elephant, and put in the giraffe". No one who was actually conversant with English could pass the test.
As such, they have nothing to do with reasoning ability. The "correct" answer is often completely wrong, like the claim that access hole covers are round "so they don't fall in", which misses the important point entirely. A circle is the minimum size cover that can't be dropped into the hole it covers. Make the cover twice as big as the hole and you have no problem. It is only under the common but special case of resource constraints that round covers are compelling.
There was also that ridiculous one about "how do you put an elephant in a refrigerator" where the "correct" answer depended on not knowing the difference between the definite and indefinite articles. The next question was "How do you put a giraffe in a refrigerator" and the "correct" answer was "You open the refrigerator, take out the elephant, and put in the giraffe". No one who was actually conversant with English could pass the test.
There was also that ridiculous one about "how do you put an elephant in a refrigerator"
Don't tell me someone has used that as an interview question? That's a silly kids joke, after which you'd laugh childishly. There even was a follow up question, if an elephant and a giraffe would race, who'd win to give the other guy a chance to redeem himself.
The joke works a lot better with languages without definite and indefinite versions of nouns, like Finnish, and you mess up the joke with english where using the definite preposition would ruin the joke, and the indefinite form is not honest.
Don't tell me someone has used that as an interview question? That's a silly kids joke, after which you'd laugh childishly. There even was a follow up question, if an elephant and a giraffe would race, who'd win to give the other guy a chance to redeem himself.
The joke works a lot better with languages without definite and indefinite versions of nouns, like Finnish, and you mess up the joke with english where using the definite preposition would ruin the joke, and the indefinite form is not honest.
You might be interested in this page:
http://en.wikipedia.org/wiki/Reuleaux_triangle
There is in fact a class of shapes that have the property that they can't fall into the hole which they cover (presuming a lip).
In addition to the above reason about it being the most efficient way to cover a hole, a round cover is also easy to move if heavy (you can roll it), very useful for something that likely has to be sturdy but also move-able.
There is in fact a class of shapes that have the property that they can't fall into the hole which they cover (presuming a lip).
In addition to the above reason about it being the most efficient way to cover a hole, a round cover is also easy to move if heavy (you can roll it), very useful for something that likely has to be sturdy but also move-able.
I can't help but notice your username, your critique, and then think of this: http://www.telegraph.co.uk/history/world-war-two/11151478/Co... (WW2 Bletchley Park using a crossword puzzle as a recruiting tool).
Here's the difference: Bletchley Park didn't have anything else. There were no programmers. There were no github repos. There wasn't anything, really. All kinds of proxy measures used to be used (for instance, I've heard there's a correlation between musical talent and programming ability).
Those measures were better than nothing, but not better than a good measure.
Edit, because I want to amplify on this a bit.
In the absence of any other measure, I'm willing to believe that someone who's good at brain teasers is somewhat more likely to be a good programmer than someone who isn't (though the correlation isn't going to be perfect, by any means).
The thing is that I can also believe that someone who's good at brain teasers is more likely to be a good surgeon or mechanic than someone who isn't.
Yet we don't use this type of question when we're interviewing surgeons or mechanics. Why not?
Those measures were better than nothing, but not better than a good measure.
Edit, because I want to amplify on this a bit.
In the absence of any other measure, I'm willing to believe that someone who's good at brain teasers is somewhat more likely to be a good programmer than someone who isn't (though the correlation isn't going to be perfect, by any means).
The thing is that I can also believe that someone who's good at brain teasers is more likely to be a good surgeon or mechanic than someone who isn't.
Yet we don't use this type of question when we're interviewing surgeons or mechanics. Why not?
One possible answer to that question, presumably not the one you're thinking of, is that those jobs are largely mechanical and require less creativity or generalized problem-solving ability than software engineering.
Edit: I don't mean to suggest that I think these kinds of questions are good for hiring software engineers, just that your argument for why that isn't the case may have some holes in it.
Edit: I don't mean to suggest that I think these kinds of questions are good for hiring software engineers, just that your argument for why that isn't the case may have some holes in it.
Before World War 2 crypto was done by linguists, not mathematicians. A lot of the work was like solving cryptgrams. So a crossword puzzle was actually a pretty reasonable test.
Nobody mentioned Feynman's work for "Thinking machines" A couple more Feynman computing links: https://www.youtube.com/watch?v=EKWGGDXe5MA http://www.scribd.com/doc/52657907/Feynman-Lectures-on-Compu...