Calculus Made Easy (1914) [pdf] - <AUTHOR> http://djm.cc/library/Calculus_Made_Easy_Thompson.pdf <comment><USER2> MIT recorded a set of Calculus video courses back in 1970s that they have since made publicly available. It is taught by a lecturer named Herbert Gross. His style of lecturing is clear, he states why things are defined the way they are and derives everything from first principles. There is an unusual mix of rigor and focus on building understanding - where everything comes from. It also taught me that math is about reasoning logically and rigorously and we shouldn't always rely on intuition (at least while doing math). Deriving almost all the basic calculus results that were drilled into me from the basic concept of a limit, deltas and epsilons was really refreshing.

Compared to more recent OCW calculus videos, I found this to be better in terms of respecting the learner's intellect, presenting the whole proof rigorously and teaching the student to think a certain way.

Calculus Revisited: Single Variable Calculus | MIT OpenCourseWare - [https://ocw.mit.edu/resources/res-18-006-calculus- revisited-...](https://ocw.mit.edu/resources/res-18-006-calculus-revisited- single-variable-calculus-fall-2010/index.htm)

Complex Variables, Differential Equations, and Linear Algebra - [https://ocw.mit.edu/resources/res-18-008-calculus- revisited-...](https://ocw.mit.edu/resources/res-18-008-calculus-revisited- complex-variables-differential-equations-and-linear-algebra- fall-2011/index.htm)

Calculus Revisited: Multivariable Calculus | MIT OpenCourseWare - [https://ocw.mit.edu/resources/res-18-007-calculus- revisited-...](https://ocw.mit.edu/resources/res-18-007-calculus-revisited- multivariable-calculus-fall-2011/index.htm)

<comment><USER3> I just had a look at the first video in the first course on YouTube [0] and was delighted to see Herb Gross responding in the comments. Clearly this is a man who loves his subject and loves introducing it to others.

[0] [https://www.youtube.com/watch?v=MFRWDuduuSw](https://www.youtube.com/watch?v=MFRWDuduuSw)

<comment><USER4> Yes, what a gem of a man.He also posted his email address in the comments for a young high school student for any further help. He is 88 years old now, I hope he is in good health.

</comment></comment></comment><comment><USER5> That PDF is just a bunch of scanned images of the book. It's large and cumbersome in many readers.

There is a _much_ better PDF at Project Gutenberg [1].

The Gutenberg PDF is only 1.9 MB, compared to 12 MB for the scanned image PDF.

The Gutenberg page for this book [2] also has a link to the LaTeX source for the PDF.

[1] [http://www.gutenberg.org/files/33283/33283-pdf.pdf](http://www.gutenberg.org/files/33283/33283-pdf.pdf)

[2] [http://www.gutenberg.org/ebooks/33283](http://www.gutenberg.org/ebooks/33283)

<comment><USER6> You say 1.9MB, the Gutenberg page says 1.8MB, and the download itself is only 1.18MB thanks to gzip. The main difference is that the Gutenberg PDF is a transcribed, cleaned-up version.

As much as this probably makes me sound like an audiophile, I actually prefer the raw scans over what may essentially be a reprint. They show all the blemishes, unofficial additions, and other marks that make the book look more "real" and give it character.

In this instance, the raw scan has a picture of the cover, as well as an interesting note handwritten near the beginning: "Property of Edward M Sumner" with an address. IMHO these sorts of historical artifacts are worth preserving too. I've come across scans with random notes, bookmark fragments, and newspaper clippings included, and it's always fun to ponder how they got there. (Who is this person and how did he get the book? Is he the one who scanned it? Etc.)

<comment><USER7> This is why I love used books. My copy of Schopenhauer's collected essays has gone through 4 owners since 1914, all 4 of whom have signed and dated the front cover, all of 4 of whom have marked and underlined at different spots (including, now, myself). My copy of Riverside Chaucer went through two students before me. And they all pick up their own unique scents along the way (my girlfriend jokes that I only buy books to smell them).

<comment><USER8> I'm with you guys! This book has some serious character. The cover, handwriting, imperfections, and on top of it all, the writing style.

The problem with used books tho is that sometimes I find hair. Ugh.

<comment><USER9> Might be proof of DNA of a previous owner. Depending on the historical value that could be golden

</comment></comment></comment></comment></comment><comment><USER10> I'm embarassed somewhat to say this, but over the past few weeks I've been taking the courses on Khan Academy on mathematics. I'm nearly 30.

and I'm not talking about brushing up on my linear algebra, that comes later, I'm talking high school level mathematics, stuff that I've largely forgotten or didn't "get" first time round.

I've seen these "machine learning for hackers!" articles who try to dish out a bit of maths saying that's all you need, but I don't think you can escape the fact that sometimes you just need to start from the beginning and work your way up

<comment><USER11> I don't think anyone can ever fault you for taking the initiative and learning it in your own time.

I feel the same way though, I've been looking back through some basic algebra on Khan Academy too because I feel maths is very much my weak point.

<comment><USER12> My mom always told me I'd need better Math grades to become a programmer.

Since the 2nd program I ever wrote was a script to do my math homework for me, I laughed at her.

Then I failed to pass the first year of CS bachelor. Twice.

I am very glad to see this most excellent book here, and will add it to my collection.

<comment><USER13> How did that happen? The required math courses got in the way?

<comment> J-J Also attempting to finish CS BS but I have hit a wall in my late 30s unable to pass pre-calc. I shudder at the daunting levels of Calc that come after to the point that I'm debating switching majors just to "get a degree".

<comment><USER14> This may not work for you, but I honestly didn't understand calculus until I worked through Knuth's _Concrete Mathematics_. There's a portion of it detailing rules on summations, which were (I realized at the time) the discrete equivalent of integration (summation of functions over integers versus integration which is summation of continuous functions). With my (stronger) CS than math background, it just "clicked" for me. You could check out the book from your university's library and see if this material helps you. I can't put my finger on which specifically now (too many years later) but various calculus concepts just fell into place as I worked through those portions of the book.

</comment></comment></comment></comment></comment></comment><comment><USER15> Summer of 1980, going into my senior year in high school, I mentioned I'd be taking Calculus next year to a co-worker a couple years older than I. He said he had the best book in the world on Calculus, and he loaned me his copy of Silvanus P Thompson's _Calculus made easy_. I thoroughly enjoyed that book, benefited from its intuitive explanations, and forever appreciated his recommendation.

If I may similarly influence anyone here, for themselves or someone they know, to read _Calculus made easy_ to supplement their calculus coursework, I will be happy to have paid the favor forward in some small way.

By the way, Kalid Azad may be our modern day Silvanus P Thompson. And he has better tools[1], which he wields masterfully, than just pen and paper. Recommended too.

[1] [https://betterexplained.com/](https://betterexplained.com/)

<comment><USER16> Would you happen to know of any websites, video series, books, etc that would be in the same vein as these 2 sources but geared towards very young students (elementary/middle school math)? ...so that they can understand it conceptually from a young start.

EDIT: I'm working through Khan Academy with one of my kids...would like to find other resources as well.

<comment><USER15> Hmm, how about a technique rather than a resource...

Look for opportunities to expand what they're doing in school. For example, after my kids had covered place values in school, I taught them binary. Their knowledge of base 10 is so much more robust when they learn base 2 as well.

Point is, I bet you already know plenty to be that ideal resource you seek for them. Good for you for wanting to start early.

<comment><USER16> Thanks for that affirmation. I actually taught them binary counting too over a weekend a few months back...I was amazed how quickly they were able to pick up on it (3rd and 5th graders). With limited time/energy, I was hoping to find some great resources to add to what I can provide them individually.

</comment></comment></comment></comment><comment><USER7> In a similar vein: "Probability Through Problems": [https://archive.org/details/springer_10.1007-978-0-387-21659...](https://archive.org/details/springer_10.1007-978-0-387-21659-1)

I love this book. What's the best way to learn a mathematical field? To discover it yourself, piece by piece!

I wish this were a series.

<comment><USER17> It _is_ a series: [http://link.springer.com/search?facet- series=%22714%22&facet...](http://link.springer.com/search?facet- series=%22714%22&facet-content-type=%22Book%22) .

</comment></comment><comment><USER18> I have an embarrassing amount of Calculus books. My dad taught the subject in a high school and community college; I suppose I have a soft spot for it. "Calculus Made Easy" is a good book though I do think there are better ones these days. Some of the lexicon has changed and there are topics covered in a modern Calculus textbook that aren't covered in the original book (that I personally think are worthwhile spending time on). The updated version with Martin Gardner does have blurbs where necessary to point it out. The Kline book is a MUCH larger read, but is what I would recommend if you want a reasonably priced Calculus book that's easy to grok. Otherwise, I think it's hard to go wrong w/ the Stewart books. Work through the problems as they do in the book, you will come away w/ what you need. Finally, if you want a whirlwind tour, Calculus for Dummies by Mark Ryan is great.

Time spent learning Calculus is worthwhile; and if nothing else, understand the fundamental theorem. Overwhelmingly impressive.

</comment><comment><USER19> For what it's worth, this is available as a much leaner pdf [1] on Project Gutenberg now, including the TeX source that some kind person used to update it.

[1]: [http://www.gutenberg.org/ebooks/33283](http://www.gutenberg.org/ebooks/33283)

</comment><comment><USER20> The prologue is 100% dead on and what I have always thought in terms of the easy part of calculus needs to be taught early. I would have never been able to vocalize what he said in the short half page of text.

We teach math backwards. We have a population that can barely do 4th grade arithmetic and it is socially okay.

Children and people believe that decimal points are accurate and that fractions are abstract when the exact opposite is true. 1/3 of a pizza is real and 0.333333 is a fake number.

We also teach movement and change as a word problem i.e. a train leaves Chicago at 25 MPH and another train leaves Flint, MI at 35 MPH when will the trains meet? That answer is an estimation of an unattainable constancy but people believe it is logical conclusion.

Pre-Calculus (needs to be repackaged with the idea of the one consistent in our world is change) should be taught before Algebra and Geometry. Make math into something where people can truly understand abstract and concrete. People actually think calculus is a hyper abstract algebra when in fact it is putting math into real world solutions.

The number one problem is calculus is 100% dependent on the teacher. A great teacher will make this work and a lower skilled teacher can absolutely kill almost all learning.

<comment><USER21> I think you this will interest you. Its a mathematician's lament on how the current system of teaching math is wrong.

[https://www.maa.org/external_archive/devlin/LockhartsLament....](https://www.maa.org/external_archive/devlin/LockhartsLament.pdf)

</comment></comment><comment><USER22> I assigned this in an Honors Calc II class I taught at a state university.

The main text was Stewart (decided at the department level), but I was teaching the Honors section which provided a good opportunity for me to ask for something extra. I had my students read this book alongside Stewart, and write weekly short essays comparing the two approaches. Many of the students turned in some quite good writing.

This is an outstanding book.

</comment><comment><USER23> Heavens - I'd have never guessed titles like '~ Made Easy' were as old as that.

I don't know why exactly, it just sounds modern.

<comment><USER24> 1914 is pretty modern.

<comment><USER23> It's all relative. Obviously I mean that it sounds vastly more recent than 1914 to my ear.

And anyway, I confess I don't know the industry at all, but I doubt anyone would talk about 1914 as representing 'modern publishing'.

<comment><USER24> A lot of the elements of what we'd call "modernity" were either introduced or became widespread in the course of the first World War so I'm not trying to just be a jerk here; I think it really is a useful dividing line.

<comment><USER23> I'm not sure I agree to it being anything stronger than a 'catalyst' period, but regardless; as elsewhere, by 'modern' I meant 'more recent than it is'.

</comment></comment></comment></comment></comment><comment><USER25> I learned calculus from this book, as did my dad, and my grandfather. My daughters will learn from this book.

</comment><comment><USER26> Good lord. I somehow took (and passed!) a year of high school calculus plus a semester in college, and I never had a good sense for the word "Integral" in a math context as anything but arbitrary jargon. _And_ I've spent a not-tiny amount of time with BetterExplained's calculus. 30 seconds with this book and it's obvious. Now I'm making connections with the French (of which I have barely any, but any port in a storm) and it's solid in my mind.

Well. Now I have to read the whole thing I guess.

</comment><comment><USER27> After scanning for a few minutes, I was amazed at how readable the book is given its age and my experience with books of similar age.

The book also does appear to go out of its way to keep language simple. For example:

 _We call the ratio dx /dy "the differential coefficient of y with respect to x." It is a solemn scientific name for this very simple thing. But we are not going to be frightened by solemn names, when the things themselves are so easy. Instead of being frieghtened we will simply pronounce a brief curse on the stupidity of giving long crack-jaw names; and, having relieved our minds, will go on to the simple thing itself, namely the ration dx/dy._

</comment><comment><USER28> It's crazy the kids have to pay hundreds of dollars for the horrible books the colleges require when brilliant things like this can be had for free...

<comment><USER29> It's not rare that supports the people teaching the class. Nothing like pushing your own book to students that just _have_ to buy it. In some cases the books don't even get used.

<comment><USER30> > Nothing like pushing your own book to students that just have to buy it.

This is a very small fraction of what goes on -

1) Many many professors have not written a/the book

2) You're not going to sell 1000000's of books through the 1 class you teach every semester. A few, yes. But lots, no.

</comment></comment></comment><comment><USER31> Just about missed the attribution in the epigraph:

 _What one fool can do, another can. -Ancient Simian Proverb_

Monkey see, monkey do?

<comment><USER32> A fool that can plainly explain matters to another fool is not a fool.

</comment></comment><comment><USER33> This is an incredible book. I'm a visual thinker, and while this book lacks all the glossy pages of illustration found in a modern Calculus textbook, the writing style helps develop that visual intuition. In the same vein of concise Calculus books, Serge Lang's Short Calculus is also great (if you need a refresher, or if you're just starting out).

[https://www.amazon.com/Short-Calculus-Original- Undergraduate...](https://www.amazon.com/Short-Calculus-Original- Undergraduate-Mathematics/dp/0387953272)

</comment><comment><USER34> This is, actually, a really good book. Don't let the cheesy title throw you off. I learned more in the first few chapters than I did after a semester of calc classes. Highly recommended.

</comment><comment><USER35> Reading it as a kid I wasn't sure I trusted the author - Silvanus P. Thompson FRS ('FRS' \- which I knew to be something rather prestigious) when he wrote in the prologue "Being myself a remarkably stupid fellow, I've had to unteach myself the difficulties . . . What one fool can do, another can."

</comment><comment><USER36> Why didn't any one tell me about this book when I was younger! This is so good. :)

<comment><USER37> As someone who struggled through calculus, this book would have made a huge difference for me. Just reading through the first few pages brought a smile to my face that someone could so plainly explain these critical concepts in such a familiar way. Why didn't my professors do that?

<comment><USER29> > Why didn't my professors do that?

Because to them it's obvious. Most maths teachers are so far ahead of the students they forgot they once were students themselves.

I've had 3 different ones in high school and the difference was incredible. All the way from 'only the best students learn anything' to 'everybody _earns_ at least a passing grade'.

Maths and physics were the classes where the quality difference between the teachers stood out the most.

<comment><USER38> > Because to them it's obvious.

And to them it's wrong! Much is said in this book which is difficult (but not impossible) to rigourously justify. It took centuries for calculus to be placed on a rigourous mathematical foundation; this foundation (called "real analysis", largely developed in the 19th century) is quite different from the intuitive ideas presented in this book. The presentation here (in particular the idea that dx² is negligible) _can_ be made rigourous through "non-standard analysis", but this 20th century development is less-known (in fact, unknown to many mathematicians) and perhaps even more difficult than real analysis.

Rigour is not necessary to understanding, and can even be fatal to understanding, but it's how mathematicians work, and generally mathematics is taught by mathematicians.

<comment><USER39> > this foundation (called "real analysis", largely developed in the 19th > century) is quite different from the intuitive ideas presented in this book. > ... (in particular the idea that dx² is negligible)

Thank you for posting this! Such things always bothered me in high school, seemed like approximations that ought to bite you in the behind at least in some corner cases. Another example from TLA:

> dy = 2cos(θ + 1/2 dθ) · sin 1/2 dθ

> But if we regard dθ as indefinitely small, then in the limit we may neglect > 1/2 dθ by comparison with θ, and may also take sin 1/2 dθ as being the same > as 1/2 dθ. The equation then becomes:

> dy = 2cosθ × 1/2 dθ

This again seems like very sloppy and careless kind of approximation that ought to bite you in the back - but knowing there are just (supposed-to-be) intuitive non-rigorous methods, and that these have actual rigorous backing, somehow soothes me.

<comment><USER40> But this is true of every level of mathematics. See humorous proofs that 2=3 amounting to manipulations like 0 _a = 0_ b, cut the zeros, a=b. This is no fault of "nonrigorous elementary algebra", it's a matter of remembering all notations are abbreviations and you have to know how to manipulate them.

You can get away with dy and dx if you just think "I'm not writing integral signs because they're annoying" and remember the rules of working with integrals. This is how stochastic differential equations work -- they're not even differential equations because Brownian motion is not differentiable, they're just notation.

</comment></comment></comment></comment></comment></comment><comment><USER41> Since no one else has mentioned it, there is an updated edition available in print, with updates by Martin Gardener.

<comment><USER42> > ... a 1998 update by Martin Gardner is available from St. Martin's Press > which provides an introduction; three preliminary chapters explaining > functions, limits, and derivatives; an appendix of recreational calculus > problems; and notes for modern readers. Gardner changes "fifth form boys" to > the more American sounding (and gender neutral) "high school students," > updates many now obsolescent mathematical notations or terms, and uses > American decimal dollars and cents in currency examples.

[https://en.wikipedia.org/wiki/Calculus_Made_Easy](https://en.wikipedia.org/wiki/Calculus_Made_Easy)

Seems like a good update to a classic, but there are some in the reviews complaining about Gardner [https://www.amazon.com/Calculus-Made-Easy-Silvanus- Thompson/...](https://www.amazon.com/Calculus-Made-Easy-Silvanus- Thompson/dp/0333772431)

</comment></comment><comment><USER43> The prologue had me hooked... I have never read anything like this in a text book. The self-deprecating humor immediately disarms you if you're the type that would go into something like this intimidated. I am definitely reading this.

</comment><comment><USER44> Oh wow. Imagine typesetting that in hot metal, many many decades before TeX and LaTeX!!

</comment><comment><USER45> I've been looking for something similar to this but for Algebra, Trig, etc. before relearning Calculus and came across this: Mathematics For The Pracicle Man by Howe (1918?) [http://www.aproged.pt/biblioteca/mathematicsforthehowe.pdf](http://www.aproged.pt/biblioteca/mathematicsforthehowe.pdf) It's targeted to Engineering students and it's not lengthy, won't take me two years to learn. Hopefully it'll be of same quality as Thompson's book?

</comment><comment><USER46> I love calculus, it's such an amazing collection of fascinating, elegant (and useful!) concepts that give you a transformative insight on mathematics in general. It's very frustrating to see it taught so poorly so often though.

One problem that teaching calculus has is that it's very dependent on having a solid foundation in other mathematics such as advanced algebra, trig, etc. In today's school systems that encourage gaming the system as students and teaching to the test as educators it's rare for most students to actually understand or be competent with material they've allegedly studied. When they hit something that starts off where they left off and builds upwards, if they have any weaknesses in that foundation it will show immediately and slow them down immensely.

Add on to that all the other problems of typical calculus instruction such as a desire to make it hard as a matter of protecting calculus education as a status symbol for "smart" people, the ability to ratchet up the difficulty arbitrarily through requiring memorization of a potentially infinite set of "trivia" (every trig. identity, every method of differentiation/integration, and so on), while generally not concentrating on the abstract concepts or the fundamentals.

</comment><comment><USER47> There is a 1998 update to the book with "modernized" english (I think it is clearer while preserving a dated style) and some additional chapters. ISBN-10: 0312185480

</comment><comment><USER48> It's funny that a book from 1914 is formatted in a way that it is much easier to read on my mobile phone than pretty much anything I can download from google books.

</comment><comment><USER49> IIRC this the book Richard Feynman said he checked out of the library and learned calculus from. Also, Feynman made comments similar to those in the Prologue.

<comment><USER50> no that was Calculus for the practical man

[http://www.goodreads.com/book/show/7398477-calculus-for- the-...](http://www.goodreads.com/book/show/7398477-calculus-for-the- practical-man)

<comment><USER51> Feynman had read both books. He mentioned the prefatory quote from 'Calculus Made Easy' in an interview given to Omni Magazine in 1979:

"... I had a calculus book once that said, 'What one fool can do, another can'..."

I have this in Chapter 9: 'The Smartest Man in the World' in Feynman's book 'The Pleasure of Finding Things Out'.

<comment><USER50> Thanks for the correction, I didn't know that

</comment></comment></comment></comment><comment><USER52> It's for sale on Amazon: [https://www.amazon.com/Calculus-Made-Easy-Silvanus- Thompson/...](https://www.amazon.com/Calculus-Made-Easy-Silvanus- Thompson/dp/0312185480/ref=sr_1_1?s=books&ie=UTF8&qid=1492741701&sr=1-1&keywords=calculus+made+easy)

</comment><comment><USER53> In Italy there is a "similar" (in the sense that it manages to explain calculus in a friendly and easy manner) book, that has been re-edited and re- published since - I believe - 1929 or so:

[https://books.google.it/books?id=oHPmx_v1H6QC&pg=PP5&hl=it&s...](https://books.google.it/books?id=oHPmx_v1H6QC&pg=PP5&hl=it&source=gbs_selected_pages&cad=2#v=onepage&q&f=false)

the original is French, the Author Gustave Bessiere was an engineer, mathematician and inventor:

[https://books.google.it/books/about/Le_calcul_intégral_facil...](https://books.google.it/books/about/Le_calcul_intégral_facile_et_attrayant.html?id=d7tKMQAACAAJ&redir_esc=y)

I don't think they are (yet) copyright free, though.

</comment><comment><USER54> This popped on my twitter yesterday, that single page was more effective than 10 years of sweating. Speechless.

</comment><comment><USER55> I love how the first page (Ch. 1) tries to show that 'terrifying' calculus symbols have very simple meanings, and so there's no reason to run away.

Less pleased, though not at _all_ surprised, that the book addresses 'fifth form boys', with no mention of girls.

</comment><comment><USER56> As someone who dropped out of Cal II, the first few paragraphs of this book gave me more understanding than I ever had in college... Either I was very lazy, or my teachers couldn't express these simple ideas clearly, or both.

</comment><comment><USER57> Fun fact: The author Silvanus Thompson was an early pioneer of what is now known as transcranial magnetic stimulation. You can see him posing with his head in a device for testing neurophysiological effects of alternating magnetic fields in figure 4 of this paper: [http://rsnr.royalsocietypublishing.org/content/61/1/5.figure...](http://rsnr.royalsocietypublishing.org/content/61/1/5.figures- only)

</comment><comment><USER58> This book is staggering. I'm on page 1. I've read a couple of dozen lines. This has explained more about calculus then a decade and a half of seeing related concepts.

</comment><comment><USER59> I believe this was Feynman's favorite book on calculus.

<comment><USER60> actually I believe that was "Calculus for the Practical Man" by J.E. Thompson and it is also an excellent read.

</comment></comment><comment><USER61> So many of these old textbooks are much clearer than ones of today. And they're no-nonsense, "What one fool can learn, another can learn."

</comment><comment><USER62> I read this book when I was 14, it belonged to my grandfather. I'd completely forgotten about it but seeing it has really brought back memories.

</comment><comment><USER63> This looks like a brilliant resource.

My problem with advanced math is not so much the understanding of principles but the application of these to solve new problems creatively.

I was able to master partial differential equations and pass exams but was never able to apply what was learned to solve new problems which I found very frustrating and was what ultimately led me to not pursue a career in the field.

</comment><comment><USER64> It's like "Calculus for dummies" except with pounds, shillings and pence, and Mrs. Ayrton's electrical arcs.

<comment><USER18> There is an actual "Calculus for Dummies", written by Mark Ryan, it's a great book.

</comment></comment><comment><USER65> Wish my prof in college gave this as a course reading.

</comment><comment><USER66> In my experience, everything is easy if you DON'T try to learn it using analogies and metaphors.

<comment><USER67> Terrible advice! I tell all of my students to find _as many_ analogies as they can. You can never lose by increasing the number of ways in which you understand something. Analogies, some may argue, are at the heart of mathematics.

> Mathematics is the art of giving the same name to different things

Poincare.

> The art of doing mathematics consists in finding that special case which > contains all the germs of generality

Hilbert.

> The vast majority of us imagine ourselves as like literature people or math > people. But the truth is that the massive processor known as the human brain > is neither a literature organ or a math organ. It is both and more.

John Green.

> Sometimes I think that creativity is a matter of seeing, or stumbling over, > unobvious similarities between things - like composing a fresh metaphor, but > on a more complex scale.

David Mitchell.

There is an ounce of truth in what you say -- metaphors can be abused to draw false conclusions. This does not mean one should cower from using them.

<comment><USER66> Everyone has their own philosophy of mathematics. To me, the core idea is the idea of representations, such that those representations allow you to extract patterns (aka similarity or commonality) from various cases.

<comment><USER68> I can't help but indulge a bit and now ask whether or not we can't extract a common pattern from the two representations of mathematical cognition offered by yourself and GP. :-)

<comment><USER66> Not here but may be on "meta hacker news".

</comment></comment></comment></comment></comment><comment><USER69> Does anyone have a recommendation in the similar vein for probability and statistics?

</comment><comment><USER70> That's a great prologue. A foreshadowing of the for Dummies/Idiots books.

</comment><comment><USER71> Thanks for this - I had not heard of this book, and it looks remarkable!

</comment><comment><USER9> First chapter alone is a jewel. This is how great teachers sound like!

</comment><comment><USER72> I have nothing to say other than that I adore this book

</comment><comment><USER73> i know this is supposed to be a beginner textbook, but his discussion of infinitesimal geometry uses an awful amount of Scheme Theory to justify.

</comment><comment><USER74> Disappointing, I thought this was about making renal calculus...

(joke)

</comment><comment><USER75> Great book! I have a hard copy, really recommended!

</comment><comment><USER73> these figures are so exquisite and the typography lazily guides me through

</comment><comment><USER76> This is a good book. But on page 5 you have an error: it should say _trillionth_ instead of billionth. I find myself liking your approach, though. You should change the font and insert some more diagrams.

Oh, what's that... you can't just republish instantly because electronic computers haven't been invented yet? Well, just iterate and do things that don't scale :)

<comment><USER77> It's actually circa 1914 British usage rather than an error.

<comment><USER76> Really? What'd they call a one followed by nine zeros then?

<comment><USER78> A milliard.

The word is still used by countries that use the 'long scale', which has the nice property that a billion = (1 million)^2 and a quadrillion = (1 million)^4 etc. If you can count in greek this also means that an n-illion times an m-illion equals an (n+m)-illion.

<comment><USER30> This strikes me as a vastly superior way of doing things..

Any insight as to why things went 'the wrong way'?

<comment><USER39> Apparently [1], both ways of counting originate from France. This 'superior' way came first and was adapted by the British, then our current way of naming was created and adopted by the US. Wiki says this one then became the standard because of USA's dominance in the financial world.

[1] [https://en.wikipedia.org/wiki/Names_of_large_numbers#Extensi...](https://en.wikipedia.org/wiki/Names_of_large_numbers#Extensions_of_the_standard_dictionary_numbers)</comment></comment></comment></comment></comment></comment>


Free Internet porn isn't unfair competition to pay sites - <AUTHOR> http://arstechnica.com/tech-policy/news/2011/02/appeals-court-free-porn-isnt-unfair-competition-to-pay-sites.ars?utm_source=rss&utm_medium=rss&utm_campaign=rss

<comment><USER2> If the decision turned out differently, Microsoft would have grounds to sue every F/OSS dev with a product similar to something MS is selling.

<comment><USER3> True, but open source developers aren't known for the piles of money they're sitting on.

Besides, F/OSS has never been a huge threat to Microsoft. They're the ones that set the price of things like web browsers to $0, and they came mostly late to the party for serious server deployments (vs. IBM, SUN, Linux, etc.)

</comment></comment><comment><USER3> If they won this lawsuit, would that let Classmates.com shut down Facebook?

I love how the judges decided it was a SLAPP lawsuit, which means not only is the lawsuit baseless, but it's obviously completely ridiculous.

</comment><comment><USER4> If tube sites steal content why don't they simply get sued for copyright infringment?

<comment><USER2> They don't steal content, they give it away, thus undercutting for-pay sites. They were trying to pull the 'unfair competition' angle.</comment></comment>


Cinnamon 2.0: What's new for users - <AUTHOR> http://segfault.linuxmint.com/2013/10/cinnamon-2-0-released/

<comment><USER2> > Becomes An `Entire Desktop Environment`

</comment><comment><USER3> Kudos for this major release !</comment>


The Bubble, she gonna burst - <AUTHOR> http://sdtimes.com/bubble-gonna-burst/

<comment><USER2> I'd describe this as "could have been written by a Markov chain" but that does a disservice to Markov chains.</comment>


Uber self-driving test car involved in accident resulting in pedestrian death - <AUTHOR> https://techcrunch.com/2018/03/19/uber-self-driving-test-car-involved-in-accident-resulting-in-pedestrian-death/ <comment><USER2> [https://news.ycombinator.com/item?id=16619917](https://news.ycombinator.com/item?id=16619917)

1400+ points</comment>


Transit App: They have lots of resources.… But then again… we have Anton. - <AUTHOR> https://medium.com/@transitapp/transit-maps-apple-vs-google-vs-us-cb3d7cd2c362#.d7g9rth7t <comment><USER2> You can see where my head is. Anton is person who is an algorithms designer. I was thinking it was the parallel supercomputer [https://en.wikipedia.org/wiki/Anton_(computer)](https://en.wikipedia.org/wiki/Anton_\(computer\)) . I couldn't figure out why a molecular dynamics computer would be good for a transit app! :)

</comment><comment><USER3> I appreciate the map nerdery, having worked with a bunch of geo nerds, but I also want to say this is my go-to transit app. It provides features like traditional mapping apps (routing) and features like One Bus Away but without required knowledge of routes.</comment>


Mental Models I Find Repeatedly Useful - <AUTHOR> https://medium.com/@yegg/mental-models-i-find-repeatedly-useful-936f1cc405d <comment><USER2> Interestingly, I find my favourite nitpick: Ockam's razor. The article quotes it as "The simplest solution is usually the correct one". This is a common misinterpretation of it and it's interesting that the quote links to the wikipedia page that has a better statement: "Among competing hypotheses, the one with the fewest assumptions should be selected."

The key problem is equating simplicity with correctness. This is usually disastrous. Once you feel that something is "correct" you stop looking for ways to falsify it. That's the exact opposite for what Occam's razor is used for.

Instead, if you have 2 competing hypotheses (two hypotheses for which the evidence supports both), you use the one with less assumptions. Partly because the one with less assumptions will be easier to work with and lead to models that are easier to understand. But mostly because less assumptions makes it easier to falsify.

Abusing this principle outside of the scientific method leads to all sorts of incredibly bad logic.

<comment><USER3> My conclusion on reading this discussion is that if a bunch of smart people can't agree on what Occam's razor is useful for, it isn't useful!

<comment><USER4> >> drzaiusapelord ,scoot

Occams razor does not ask that you accept the simplest explanation. It asks that one take into account as many, and only as many factors as necessary to explain a phenom. It does not promote fallacy or lessen rigour. It is a "loose leash but a tight chain"

As originally defined, it stated: Entities should not be multiplied without necessity(Entia non sunt multiplicanda praeter necessitatem).

Bertrand Russel held the principle in high regard. This quote from Newton encapsulates its application: "We are to admit no more causes of natural things than such as are both true and sufficient to explain their appearances." and simplified for scientists in this form: ""when you have two competing theories that make exactly the same predictions, the simpler one is the better" [http://math.ucr.edu/home/baez/physics/General/occam.html](http://math.ucr.edu/home/baez/physics/General/occam.html)

There is a line of scholarship that believes William of Occam (c1287-1347) never made the quote attributed to him. [http://www.logicmuseum.com/authors/other/mythofockham.htm](http://www.logicmuseum.com/authors/other/mythofockham.htm)

What is termed Occams razor by vog asQuirrel asmad and others is a statistical/logicians derivative not really of concern to most people.

</comment></comment></comment><comment><USER5> Two adjustments that I would make.

Remove Metcalfe's law. It is a massive overestimate. See [http://www.dtc.umn.edu/~odlyzko/doc/metcalfe.pdf](http://www.dtc.umn.edu/~odlyzko/doc/metcalfe.pdf) for the better n log(n) rule for valuing a network.

And I find Le Châtelier's principle generally applicable, and not just to Chemistry. It says that if you observe a system at equilibrium, and try to induce a change, forces will arise that push it back towards the original equilibrium. It is one thing to recognize this at work in a chemical reaction. It is quite another to be blindsided by it in an organization.

See [http://bentilly.blogspot.com/2010/05/le-chateliers- principle...](http://bentilly.blogspot.com/2010/05/le-chateliers-principle- not-just-for.html) for my explanation of why this holds in general outside of chemistry.

<comment><USER6> One thing I question with Le Châtelier, is how do you know which equilibrium will be pushed back towards?

Humans have a desire pro-speed and anti-risk. Supposedly, if you introduce seatbelt laws, speed increases and risk stays the same. How do you predict that in advance? Why doesn't risk decrease and speed stay the same? Or why not speed increase a bit and risk decrease a bit?

<comment><USER5> Push it back towards does not mean that it necessarily arrives at its original position. Just that it didn't wind up as far away from it as you'd naively hope.

</comment></comment></comment><comment><USER7> Ugh, maybe I'm the only one but I don't find this list useful. Not because it isn't interesting, but the implication that it will actually make you smarter. The problem today isn't information, it's knowledge. Even if you can correctly and fully understand all these models, something that could take years, you still most likely wouldn't be able to implement them, especially when they are in conflict with each other.

I think it's a much better idea to study things like critical thinking, practical reasoning and operational leadership. Back in the day hacker values stated that you could ask for directions, but not for the answer. Because the process itself was as important as the answer. Not just for amusement, but because there might not be a right answer and the next time you're confronted with a similar problem you now have some experience of making those decisions.

A great deal of "stupidity" in technology these days seem to stem from schools that promote check box answers to complex problems and the popularity of these "laws" that make people so sure of themselves that it prevents them from proper reasoning.

<comment><USER8> This list is useful for people who are already used to thinking in these ways, intuitively, by being exposed to other people and learning by osmosis. Formalizing intuition leads to easy growth.

For other people, you're right, it's about as useful as reading through a list of course descriptions rather than taking the actual courses.

<comment><USER7> "This list is useful for people who are already used to thinking in these ways, intuitively, by being exposed to other people and learning by osmosis. Formalizing intuition leads to easy growth."

That's exactly what I'm questioning though, if that's the right way to learn things. Especially with the premise of the article, there's a risk that people are just "collecting facts" to be used as anecdotes to avoid reasoning.

"For other people, you're right, it's about as useful as reading through a list of course descriptions rather than taking the actual courses."

Somewhat ironic I read course curriculums all the time to figure out which subjects are covered and what are good beginner books.

<comment><USER9> I think everything on this page is about encouraging reasoning rather than just collecting facts. If someone takes each one as a truism and blindly follows it, then yes, it would turn these mechanisms (which are supposed to help us identify and fight our own cognitive biases) into just another form of cognitive bias. That's why they're not laws, they're just handy patterns to help us reason about things that we see every day.

I'm not sure what you mean by using them as tools to avoid reasoning- they are explicitly meant to help with reasoning. I don't know what sort of reasoning could be done without incorporating any sort of logical frameworks at all. That's all this stuff is, tools to aid reasoning by identifying common patterns and antipatterns in thoughts and perceptions about the world around us. Anyone who treats these ideas as absolute laws rather than occasionally (frequently) useful abstractions is doing it wrong.

<comment><USER7> "That's all this stuff is, tools to aid reasoning by identifying common patterns and antipatterns in thoughts and perceptions about the world around us."

Identifying patterns is second to learning something. Logical fallacies are examples of bad arguments. You should first learn how to evaluate an argument [0] before trying to identify logical fallacies. Not only will you learn more, but there's a greater chance you will be able to put any given "model" in context. That people find things like logical fallacies useful is an indication that they don't understand the fundamentals.

[0] [https://www.google.com/search?q=critical+thinking+argument+e...](https://www.google.com/search?q=critical+thinking+argument+evaluation)

</comment></comment></comment></comment></comment><comment><USER10> This is super useful, I have a similar list but it also includes techniques and ideas

      * Dimensionality Reducing Transforms
      * Hysteresis, Feedback
      * Transform, Op, Transform
      * Orthogonalization for things that are actually dependent
      * Ratios, remove units, make things dimensionless

A big one, that helps me immensely, is that when I need to do a big/risky/complex task, is to imagine myself doing with with sped up time. Instantly creates an outline and list of tools that one will need.

<comment><USER11> Can you write more about "sped up time"? I'm reminded of something like this: [http://lesswrong.com/lw/mnp/travel_through_time_to_increase_...](http://lesswrong.com/lw/mnp/travel_through_time_to_increase_your_effectiveness/)

<comment><USER10> This is more metaphysical than the basic technique. If I was going to exchange the hard drive in my laptop. I would visualize the entire process, noting the questions and problems as I completed each step.

      * do I have the proper tools? Lookup special fasteners
      * I will misplace the screws, a magnet or plastic cups would help
      * It might be dirty inside, I need something to clean
      * I might drop a screw inside, tweezers
      * Could be dark, headlamp
      * cable might not stay in place, tape

It might take 20-30 seconds to run through all the steps in ones mind, anticipating problems before they arise.

</comment></comment></comment><comment><USER12> Good list! A few suggested tweaks:

Veblen goods clearly exist, but the evidence for the existence of Giffen goods is much more suspect. (Did the poor really eat more bread because the price of bread rose, or because there was an across-the-board increase in the price of all kinds of food?)

The Precautionary Principle is not just dangerous or harmful, but guaranteed suicide; as things stand right now, we are all under a death sentence. It needs to be replaced by the Proactionary Principle, which recognizes that we need to keep making progress and putting on the brakes is something that needs to be justified by evidence.

Any list that has sections for both business and programming needs some entry for the very common fallacy that you can get more done by working more hours; in reality, you get less done in a sixty-hour week than a forty-hour one. (Maybe more in the first such week, but the balance goes negative after that.)

The distinction between fixed and growth mindset is well and good as far as it goes, but when we encourage the latter, we need to beware of the fallacious version that assumes we can conjure a market into existence by our own efforts. You can't become a movie star or an astronaut no matter how hard you try, not because you lack innate talent, but because the market for those jobs is much smaller than the number of people who want to do them.

</comment><comment><USER13> A technique I often use to test a theory is to change the inputs to be the maximum and minimum possible values and see if the model still holds true. I've found it to be incredibly useful in a few specific situations.

<comment><USER14> I've always thought this _should_ be a very effective way to explain a point to someone, but in practice it rarely seems to work....maybe that saying applies, something about you can't use logic to change the mind of someone that didn't use logic to arrive at their conclusion.

<comment><USER12> That might be because you're trying to use it to argue politics, where it's less applicable; hard cases often make bad law, and you can easily end up with a straw man. It works better in science and engineering.

</comment></comment></comment><comment><USER15> I think pg also wrote an essay about a mental model that I find interesting: When in doubt, it's probably not about you.

There are many events that we usually think are related to us, but actually aren't, like your boss or customer being angry is in most cases not about you but something else.

I have looked through a lot of pg's essays but didn't find it. He probably removed it just that I can't find it (/example).

If someone else finds it, please link.

<comment><USER16> When shop personel is not friendly, we tend to think that that person is not a friendly person, as a character trait. When I'm not friendly in the same situation, it's because I didn't get enough sleep, or because I had a fight with my girlfriend that morning. So in my case it's circumstantial, temporary, not my fault, in the other person's case it's the person's fault and permanent.

What you describe is our inner voice doing the same thing. (This is my personal explanation!)

Google for "inner voice doubt" and find out more!

<comment><USER12> Yes. For another search term, the fallacy in question is sometimes called the Fundamental Attribution Error.

</comment></comment></comment><comment><USER17> I'm surprised he rates cost-benefit analyses as a 2 ("occasionally" used) rather than a 1 ("frequently" used). Making good decisions almost always requires taking a hard look at both the costs and the benefits. It cannot be overstated how often bad decisions are made because the parties involved simply neglected to factor in the costs (including opportunity costs).

I personally use cost-benefit analyses for every non-trivial decision in my life.

<comment><USER18> Yeah, the "X has a benefit, so we should do X" fallacy is really common, both in software development, politics, and most everywhere.

</comment></comment><comment><USER19> Some commenters here are saying, "I already know this stuff." Indeed. I'd be curious if people could put out a list of "advanced" mental models. For example, Bayes' theorem is more advanced than Occam's razor.

What's clearly more advanced than Bayes' theorem, and as useful? ET Jaynes' flavor of probability theory? I'd posit the more advanced version of active listening as, "being able to perform a bunch of kinds of therapy--freudian, rogerian, family and systems etc." Of course I don't mean you go get a license for these things. I'm positing them as difficult, generally-applicable life skills. I'm not claiming these are good examples; I think HN can come up with better ones.

<comment><USER20> Thinking being a flux of information, and EE telecom theory having discovered all kinds of laws about flow of information, its no surprised that those models apply pretty well to the engineering tradeoffs of general mental models of thinking or thinking about information in other contexts.

EE control theory class IS an entire senior year class on applying a model to something (a thermostat?) which isn't terribly hard, and then modeling and measuring its performance and finally optimizing the model which is pretty hard.

Shannons law explains how good ideas, noise/distraction/bad ideas, depth of concentration or maybe total volume of information, and rate of mistakes all interrelate and how changing one (or several) will affect the others in general.

There are some interesting tradeoffs in communication filter design (analog hardware or modeled in DSP) along the lines of you can freely trade smoothness in response (group delay, ripple, latency, monotonicity kinda), accuracy in response, and complexity/cost. These tradeoffs apply to everything in the world that processes things not just filter synthesis.

There is some kind of chaos theory "thing" where as feedback mechanisms become more complicated, oscillation becomes inevitable and unpredictable. Doesn't matter if we're talking about high gain amplifier design or world economic models.

This is aside from the general engineering mental models of a good engineer can freely exchange cost, reliability/safety, and performance. In fact it being enormously easier to exchange in those rather than expand, you can pretty much see thru transparent marketing that only mentions one or some factors. This applies to all of reality not mere structural engineering.

I think the optics people could say a lot about their seemingly endless stable of aberrations. There are so many effects and interactions its surprising anything optical works at all, much less works well. Optics is almost a meta law that everything interacts with everything and constants aren't.

</comment></comment><comment><USER21> I'm just getting exposed to this line of thinking and find it fascinating. Another resource I found recently was [https://www.farnamstreetblog.com/mental- models/](https://www.farnamstreetblog.com/mental-models/)

 _Disclaimer: I 'm not sure if it's derivative blogspam or legitimately insightful / original_

</comment><comment><USER22> A nice metacognitive cheat sheet.

Missing a couple interrelated mental models I find very important:

\- emergence: a process whereby larger entities, patterns, and regularities arise through interactions among smaller or simpler entities that themselves do not exhibit such properties

\- decentralized system: a system in which lower level components operate on local information to accomplish global goals

\- spontaneous order: the spontaneous emergence of order out of seeming chaos. The evolution of life on Earth, language, crystal structure, the Internet and a free market economy have all been proposed as examples of systems which evolved through spontaneous order.

</comment><comment><USER23> Could someone give me a real example of somebody using mental models in a real world application? I just find the idea of learning and studying mental models to be distracting and confusing. Pardon my ignorance.

<comment><USER24> To be honest, I think that the process is something like:

I struggle with problems and eventually find a solution,

I encounter a name for a similar solution,

as I encounter new, similar problems, I begin to recognize "how the model works",

I forget about the model when I don't use it,

occasionally I come across a list like this one where it's fun becasue it validates the usefulness of the models I've already found and introduces me to new names for ones I already have encountered.

I don't feel that a list like this is super useful to me outside of that framework-- I wouldn't take it as a "study guide".

But I feel that framework has given me a lot of personal validation and pointers on how to better deal with problems I encounter.

</comment></comment><comment><USER25> I still think Social Psychology was one of the most useful classes I ever took in college. Sure some if it is probably dated by now but the cognitive biases theories really helped me further in life.

I remember telling some class mates to take the class and they assumed it was for an easy A and not for how useful the class would be (and I went to a GaTech a long time ago and well the social sciences were just not respected like engineering disciplines at the time).

<comment><USER26> As a fellow Georgia Tech grad, I wholeheartedly concur. The course on Political Philosophy was not only one of the most challenging classes, but also the most useful in daily life. It really changed how I think about the world--so much so that I decided to to double major in international affairs/modern languages. It's a pity that the social sciences/liberal arts aren't as respected at engineering schools. Those courses were equally enriching (if not more so) to my life as combinatorics, differential equations, and quantum mechanics.

</comment></comment><comment><USER27> To the development section, I would add the concept of computational context/state, caching, and queue/event loop.

This HN comment summarizes it pretty nicely "everything in an OS is either a cache or a queue" [https://news.ycombinator.com/item?id=11655472](https://news.ycombinator.com/item?id=11655472)

Also Overton window

</comment><comment><USER28> I have a similar list of useful concepts. My goal so far this year was to expose myself to those concepts as often as possible. I made an app for my phone that displays the concept of the day on my home screen (right now it's the rhetorical concept of periodic sentences). I also made images for each of the concepts that I use as my chromecast backdrop. I've seen each of them dozens of times by now, mostly unconsciously.

So far, mixed results. I would like to say that I think of "Bayes Theorem" at the perfect time because I wrote it on a list, but that never happens. I guess I've benefitted from thinking about these concepts more, but that's almost impossible to measure. A list of 100 useful mental models has limited value if you can't hold all of them in memory at once and retrieve them at the right time. I'm still trying to come up with a solution for this. Unfortunately I think this might be a fundamental limitation of human learning.

<comment><USER29> Instead, try and think of a situation in the previous day when you might have applied it, and imagine applying it to a problem in the coming day.

</comment></comment><comment><USER30> > _What am I missing?_

In planning a strategy, I've found it helpful to consider _Win Conditions_. It forces me to think backwards from the goal, construct a dependency tree, and consider resource allocation. I first heard about it from videogames but I've also seen it in math, engineering, logistics, recipes, etc. I also pattern- match it the insight that solved the _Problem Of Points_ [0] which motivated Probability Theory. If it were on the curated list, I'd expected to find it under "models" next to cost-benefit analysis.

[0] [https://en.wikipedia.org/wiki/Problem_of_points#Pascal_and_F...](https://en.wikipedia.org/wiki/Problem_of_points#Pascal_and_Fermat)

</comment><comment><USER31> Great list, although I prefer the term "thought technology" (as coined by John Roderick) to "mental model".

<comment><USER32> So, a question back at you. Let's suppose an ontology of technological _mechanisms_. That is, describing technologies by _how they operate_. I've kicked some ideas around and come up with:

1\. Process-knowledge. Arts and practical stuff, say, agriculture, construction, boatbuilding, sailing, etc.

2\. Fuels & combustion, generally. Wood, plant and animal oils, charcoal, coal, petroleum, steam, otto, deisel, turbine engines.

3\. Materials. Functions dependent on specific properties, and abundance of materials they're based on.

4\. Power and transmission.

5\. Sensing, perception, symbolic representation & manipulation.

6\. Systematic knowledge. Science, geography, history.

7\. Governance, management, business, & institutions.

8\. Scaling and network technologies. Cities, transport, communications, computers.

9\. Sinks & unintended consequences. Pollution, effluvia, systems disruption, and their management.

"Thought technology" probably falls into scientific knowledge (models) or symbolic processing.

Thoughts?

More: [https://ello.co/dredmorbius/post/klsjjjzzl9plqxz- ms8nww](https://ello.co/dredmorbius/post/klsjjjzzl9plqxz-ms8nww)

</comment></comment><comment><USER33> On-going series on mental models at [http://www.safalniveshak.com/category/mental- models/](http://www.safalniveshak.com/category/mental-models/)

</comment><comment><USER34> His definition of a "strawman" is incomplete. It's not simply misrepresenting someone's argument, it's misrepresenting it specifically by analogizing it falsely to something similar that is easier to attack. The example he links to is a rather exaggerated strawman. I think most people would favor the strawman explanation in Wikipedia[1]

[1] [https://en.wikipedia.org/wiki/Straw_man](https://en.wikipedia.org/wiki/Straw_man)

<comment><USER35> Many of his definitions are incomplete.

</comment></comment><comment><USER36> The wrong assumption about Ockams Razor is probably the cause of so many people re-inventing the wheel.

"I don't need this big framework, I can do with much less!"

</comment><comment><USER37> How would one actually use this stuff?

<comment><USER38> This is one of those lists that would be completely unhelpful if you don't already know how to use most of what's on the list.

<comment><USER39> Agreed. It's as helpful as the other post on list of free online programming books. Needs more handholding to help people make the best use of the list.

</comment></comment></comment><comment><USER40> This book is a very handy pocket reference that overlaps with many of the ideas mentioned here:

[https://www.amazon.com/Decision-Book-Models-Strategic- Thinki...](https://www.amazon.com/Decision-Book-Models-Strategic- Thinking/dp/0393079619)

</comment><comment><USER41> This is the core of the book Peak: Secrets from the New Science of Expertise. It is a book of how to create a mental representation of what successful mental representations look like.

The most successful people, peak performers are those who have the best mental representations.

</comment><comment><USER4> I would add to the list 'revealed preference'

'... an economic theory of consumption behavior which asserts that the best way to measure consumer preferences is to observe their purchasing behavior. Revealed preference theory works on the assumption that consumers have considered a set of alternatives before making a purchasing decision. Thus, given that a consumer chooses one option out of the set, this option must be the preferred option' [http://www.investopedia.com/terms/r/revealed- preference.asp](http://www.investopedia.com/terms/r/revealed-preference.asp)

In other words "observe their actions, not their words"

</comment><comment><USER42> Are these "mental models" or just a bunch of clichés / pithy aphorisms? To me, a mental model would be something more like "visualizing possible state transitions as a directed graph" or something like that.

</comment><comment><USER43> Nice. They got Hick's law...that's one of my favorites, not so much in development, but sports. I train Brazilian jiu-jitsu, and I find substantial improvement in my reaction time by having only 2-3 well-worn options at my disposal (even 3 starts to feel crowded) in an given position, rather than a multitude of counters/attacks. When someone is trying to strangle you, go left or right is often a better choice than let's-check-the-mental-database-for- the-ultimate-move.

</comment><comment><USER44> The mental model from economics that is widely misinterpreted is comparative advantage. Most think it means you/a country etc should specialize in that which you are best at. And then free trade will work to your advantage. But it actually means that even if you are worse at producing products A and B than another country, if your ratio of A/B is better than the other country, it would be good for you to produce A and trade it to the other country for B etc. I

</comment><comment><USER45> A couple more:

Evolution

> Frequency-dependent selection: fitness of a phenotype depends on its > frequency relative to other phenotypes

> Evolutionarily stable strategy (ESS) is a strategy which, if adopted by a > population in a given environment, cannot be invaded by any alternative > strategy that is initially rare. It is relevant in game theory, behavioural > ecology, and evolutionary psychology. Related to Nash Equilibrium and the > Prisoners dilemma.

Economics

> Debasement (gold coins): lowering the intrinsic value by diluting it with an > inferior metal.

</comment><comment><USER46> Quite a few of these "mental models" are just a definition of terminology like "botnet". Come to think of it, the complete list is just definitions..

</comment><comment><USER25> I would say "Divide and Conquer" should be a 0... it is that useful and it can be applied to many many different categories.

So many things seem intractable and formidable in complexity yet once these things are broken down into pieces things become clear. The Asana CEO once talked about this. Breaking things out provides clarity and once you have clarity productivity is massively increased.

</comment><comment><USER47> If you enjoy these sort of summaries, I encourage you to check out the book "Seeking Wisdom" by Peter Bevelin [https://www.amazon.com/Seeking-Wisdom- Darwin-Munger-3rd/dp/1...](https://www.amazon.com/Seeking-Wisdom-Darwin- Munger-3rd/dp/1578644283)

</comment><comment><USER48> There is also an app from the apple app store that has most of these mental models in book form: [https://itunes.apple.com/us/book/think-mental- models/id61236...](https://itunes.apple.com/us/book/think-mental- models/id612365806?mt=11)

</comment><comment><USER49> I thoroughly enjoyed the book Inside The Box, which presents four mental models for creative problem solving. The core idea that creating rules can help creativity is a pattern toward which I think most technical people (including myself) feel averse, but actually can be beneficial when studied with an open mind.

</comment><comment><USER50> I recurrently use: _Everything is a_... [1]

Even when this model doesn't explain 100% of occurrences is great as a starting point of view to understand the main pattern of a complex system.

[1] - [http://c2.com/cgi/wiki?EverythingIsa](http://c2.com/cgi/wiki?EverythingIsa)

</comment><comment><USER51> Perfect, but how do you use these models?

Are you supposed to know all 100's of them by heart and then, in the middle of conversation, go: "Ah, but X principle says Y, therefore we will go with Z option". Is it? Am I missing something?

I mean, I'd love to use this but I don't have enough brain cells for all of those :)

</comment><comment><USER52> I'd add Amdahl's Law [1], which is about the relationship between adding resources for executing a task, and the speed-up that delivers.

[1] [https://en.wikipedia.org/wiki/Amdahl%27s_law](https://en.wikipedia.org/wiki/Amdahl%27s_law)

</comment><comment><USER53> It's an interesting list. Though I'm a bit baffled at why he has Power-law as a "1" (comes up frequently) and Heavy-tailed distribution as a "3" (rarely comes up). A power law _is_ a heavy-tailed distribution!

</comment><comment><USER54> Very underwhelming, I'm actually quite surprised that most people seem to find this useful and interesting. I mean, normal distribution, Moore's law, minimum viable product, paradox of choice... that's pretty basic stuff.

</comment><comment><USER55> under competing, I'd add OODA loops ~ [https://en.wikipedia.org/wiki/OODA_loop](https://en.wikipedia.org/wiki/OODA_loop)

<comment><USER56> Specifically the competitive aspect of getting inside an adversary's OODA loop

</comment></comment><comment><USER57> Along with the reference to Arrow's Impossibility Theorem, I'd want a reference to the fact that voting can be done in ways other than ranking, e.g. approval or score voting.

Overall, a superb list.

</comment><comment><USER58> Nice list! I really miss this one:

[https://en.wikipedia.org/wiki/Reductio_ad_absurdum](https://en.wikipedia.org/wiki/Reductio_ad_absurdum)

</comment><comment><USER59> [https://en.wikipedia.org/wiki/List_of_eponymous_laws](https://en.wikipedia.org/wiki/List_of_eponymous_laws)

</comment><comment><USER60> Have a look at the Single Responsibility and High Cohesion principles, which i think should be included in development/design

</comment><comment><USER27> Is Gabriel Weinberg related to Gerald Weinberg? No right? I've been wondering this for some time now.

</comment><comment><USER61> An article that goes straight to the point. I like it!

</comment><comment><USER62> Inflation is a mental model? Peak oil? Botnet?

<comment><USER63> I think these can be defended as mental models, even though the article doesn't do a good job of it.

We're familiar with inflation in the financial sense. But then there is also grade inflation. There is inflation of superlatives in our language, e.g. "great" and "awesome". Once we see a few examples we realise that inflation is a more general concept, and a useful one to use in explaining a lot of situations.

Same for peak oil, I think. Not sure about botnet.

<comment><USER62> I went back to look at the article again and now see that he says almost exactly what you just said. Was that there before?

<comment><USER63> Hmm.. the entry on inflation hasn't changed (doesn't say anything like what I said) but I see notes that mention grade inflation. I don't know whether that was there first time round.

</comment></comment></comment></comment><comment><USER64> Nothing ground breaking here - I imagine most readers here already use most of the author's models - but this is a nice comprehensive list, which I have not seen before.

<comment><USER65> Does anyone have a pointer to a list of these lists? Would be interesting to know what models people use on a day-to-day basis, like usesthis.com for the brain.

<comment><USER66> I've started keeping such a list actually: [redacted]

<comment><USER32> Ah, that's the first actual pinboard page I've seen -- I've been looking at/for archival tools for some time, currently Pocket.

<comment><USER66> I'd recommend it. I was grandfathered into the free plan but $11/year seems fair.

Regardless of what you settle on I'd look for the equivalent of [http://www.packal.org/workflow/alfred- pinboard](http://www.packal.org/workflow/alfred-pinboard) for whatever service and platform you use. Being able to instantly search through all fields of all items in your archive is pretty great and has changed the way I work.

<comment><USER32> Pocket has comprehensive search, which is pretty slick. The tagging feature leaves much to be desired, though it's also far better than Readability.

</comment></comment></comment></comment></comment></comment><comment><USER67> I guess what you described goes by a well-known term called 'critical thinking'?

<comment><USER32> Strictly no, though what's offered in part complements, in part substitutes, for critical thinking. Some of these _are_ components of critical thinking (or describe), much isn't.

This is a set of both guidelines and heuristics, a set of patterns, if you will, which can be applied to situations or analyses. Some give you a fast route to a simple answer (Occam's Razor), some give pause before accepting what appear to be well-founded results (Simpson's Paradox -- I've encountered that before but had largely forgotten it). Some are simply shortcuts in estimation (order-of-magnitude, and log-based math -- multiplication and division become addition and subtraction).

Critical thinking has varying definitions, but I'd generally describe it as more structured and procedural than what's offered by @wegge. See: [https://en.m.wikipedia.org/wiki/Critical_thinking](https://en.m.wikipedia.org/wiki/Critical_thinking)

</comment></comment><comment><USER68> wow, this is really useful. thank you.

</comment><comment><USER69> aka buzz words to make you sound more intelligent.

</comment><comment><USER70> Interestingly, that's about 75% of my 2-year MBA.

Sure, it's far different doing daily training to get those concepts ingrained in your mind so you don't have to actively think about them, but it's nice to see them listed like this.

Here are a couple more:

\- Overconfidence bias: we usually think we're better than the average on something we know how to do (driving) and worse than the average in something we don't (juggling), even if almost nobody knows juggling and everyone knows how to drive

\- No alpha (aka can't beat the market): you can only consistently beat the market if you're far better at financial analysis than a lot of people who do it every day all day. So don't bother trying.

\- Value chain vs. profits: you'll find that most of the excess profits in the value chain of a product will be concentrated in the link that has the least competition

\- Non-linearity of utility functions: the utility of item n of something is smaller than item n-1. Also, the utility of losing $1 is smaller than (1/1000) utility of losing 1000. This explains insurance and lotteries: using linear utility function, both have a negative payout, but they make sense when the utility function isn't linear

\- Bullwhip effect in supply chain: a small variation in one link of the supply chain can cause massive impacts further up or down as those responsible for each link overreact to the variation (also explains a lot of traffic jams)

\- Little's law: in supply chain (and a lot of other fields): number of units in a system = arrival rate * time in the system

I'll add more as I think about them.

<comment><USER71> _\- No alpha (aka can 't beat the market): you can only consistently beat the market if you're far better at financial analysis than a lot of people who do it every day all day. So don't bother trying._

I'd argue that you can have alpha if you are better informed than everybody else. Financial analysis is the craft that comes after that. So yes, if all you have is financial analysis don't bother trying to beat the market. But if you have some unique insight, some information that the market doesn't have or doesn't see, then with some added financial analysis on top you do have an advantage that you can use to generate alpha.

<comment><USER70> Sure, but insider trading is illegal. So let's say you can only rely on publicly available info, which everyone else has.

Then "unique insight" is financial analysis, plus macroeconomic analysis, etc.

In other words, if everyone have access to the same info, you can only consistently do better than the market by consistently having better analysis than the market. Everyone is seeing the same info, so you don't do better by seeing some piece of info others are not seeing, but by using different weights in your analysis than the market is using.

And even in those cases, the market might stay irrational longer than you can stay solvent.

<comment><USER71> You work with an oversimplifying model of reality.

Say you've worked in a specific industry for a long time and you know all the players. You know where the technology is, what the challenges are and where the tech is going. You know how key companies are managed, you have an idea about their goals and strategies. You know who's best positioned for what's coming. This is just general knowledge that you've acquired through your job over the years. Now say you've made enough money and retire. Because you know a thing or two about your industry you decide to buy or sell some stock. Can this be called insider trading? Perhaps. Is it illegal? Most likely not. Can you derive alpha from it? Hell yea.

<comment><USER42> Why aren't you super rich, then? If that's really true, then go do that thing you said.

<comment><USER72> Straw man

</comment></comment></comment></comment></comment></comment><comment><USER73> If the 29 minute read time is intimidating, consider this link: [https://www.farnamstreetblog.com/mental- models/](https://www.farnamstreetblog.com/mental-models/)

All the information, easier to read quickly.

<comment><USER74> It was a nine minute read for me. Medium's estimates are always off and especially so when dealing with list-type posts.

Instead of relying on how long some website says something will take to read, it's usually a better idea to scroll through once just doing scanning at the high level to get an idea of length and then read it if you want to.

</comment></comment><comment><USER75> "Spamming" is a mental model? Mmmmmkay.

<comment><USER76> Besides its original meaning (repeated uninvited bombardment with information packages) I can think of only one alternative use of the pattern: games.

For example, rocket / grenade / arrow spam in TF2, or Lucio / Hanzo / Symmetra projectile spam in Overwatch. In this context, spamming is just firing in the general direction of the enemy, hoping that some of the rounds will hit.

Maybe this generalizes to repeated application of some cheap technique that has a low probability of success, where the low chances of success are compensated by the low amount of effort per 'shot' required -- but I can't think of any more examples.

<comment><USER75> That's pretty good. Gotta applaud you.

</comment></comment></comment><comment><USER77> TL;DR; What you learn in an Economics degree.

</comment><comment><USER78> Such cynical words, besides depriving the world of a much needed listicle, will also get us downvoted. Please don't offer such awkward comments which might cause people to pause and think. Now back to my facebook feed..

<comment><USER79> We detached this comment from [https://news.ycombinator.com/item?id=12040892](https://news.ycombinator.com/item?id=12040892) and marked it off-topic.</comment></comment>


How to Destroy Your Startup in 15 Easy Steps - <AUTHOR> http://www.getpenta.com/blog/jekyll/update/2016/10/15/how-to-destroy-your-startup.html <comment><USER2> "I see this all the time. Startup founders hiding their ideas because of the fear that someone will steal it. Remember: no one cares about you. Your biggest issue is getting discovered. If someone steals your idea, that means you're doing something right."

This advice is wrong. My current successful business was the result of an Internet post from a person that had the same idea. I had more money, resources, and time, and I crushed them before they even had a chance to get their MVP perfected. They went out of business within a year.

Announcing your idea too early can bring unwanted competition with more resources than you. The key is to validate your idea before working on it. This is different than not keeping your business a secret.

<comment><USER3> But the guys you stole the idea can be succesful the same way as you.

<comment><USER2> Possibly, but why bring on more competition? From a business perspective, this is not a very good idea and will only make it harder for you to succeed.

</comment></comment></comment><comment><USER3> Your advices are still very imature, imo. Long long way ahead.</comment>


Enforcing Type Returns in Ruby with Pedant - <AUTHOR> http://superjared.com/entry/introducing-pedant-ruby-library-will-annoy-you/

<comment><USER2> If you want strong type guarantees, don't use a dynamic language. If you're able to not make such silly mistakes and enjoy the power and expression of a dynamic language, then use them, you won't miss types much at all.

I use Smalltalk daily and such type errors are so rare as to be virtually non existent. If you pay attention to what you're writing, you don't make such silly mistakes often, and when you do you usually notice it immediately when you try to use the code you just wrote.

Bolting a home-brew type system on a dynamic language just seems rather pointless, if you need it, you're not really ready to be using a dynamic language.

<comment><USER3> I find the inference that you must be a dolt ("If you're able to not make such silly mistakes ...") to want an type system to be both insulting and positively ridiculous.

A powerful type-system provides tools to _concisely_ express business/logic constraints and automatically enforce those constraints across the entirety of your codebase.

Advanced type systems are a powerful tool to enable you to write less code that is guaranteed correct. It's not a seat belt for morons like myself who apparently lack your mental caliber.

<comment><USER4> I don't think the implication was that you "must be a dolt" if you feel the need for a type system, just that you probably shouldn't be writing in Ruby. I don't expect C to handle memory for me, I don't expect Java to interface cleanly with the underlying OS, and I don't expect Ruby to enforce type declarations.

I think the point is that, if you feel like you're missing something by not having types enforced in Ruby, then you're probably using the wrong tool for the job. Sure, I could probably turn a claw hammer around and use the nail- puller to turn a screw in a pinch, but I'm not going to run a carpentry business like that.

<comment><USER3> The implication is pretty clear:

      If you're **able to not make such silly mistakes** and
      enjoy the power and expression of a dynamic language,
      then use them, you won't miss types much at all.

      If you **pay attention to what you're writing**, you
      don't make such silly mistakes often.

      Bolting a home-brew type system on a dynamic language
      just seems rather pointless, if you need it, **you're not
      really ready to be using a dynamic language.**

As an intelligent software engineer I do pay attention to the code that I write and have come to the conclusion that advanced type systems, as a tool for writing concise and correct code, provides me with an overall win.

Your mileage may vary.

That said, I'd be very willing to bet that a Ruby type checker/static analyzer will find bugs (some of them serious) in your codebase, despite pervasive unit tests. That has certainly been my experience with Python+pylint, and Erlang+dialyzer.

<comment><USER2> No offense was meant though I see how you could take it that way. The difference lies in what type system we're talking about. You're talking about powerful type systems, I'm talking about most type systems.

The kinds of mistakes a Java'ish type system prevents you from making are fairly trivial; we're not talking about Haskell here where type system can actually encode most of the biz rules. The home brew system being bolted onto Ruby here is not a powerful type system, it only prevents trivial mistakes that are easily avoided by most who like and use dynamic languages to begin with.

Static type advocates are always telling us about all the mistakes their type systems prevent, and then go on to describe scenario after scenario that we just don't actually run into. They're solving problems that really just aren't problems for us. They seem to really believe you can't write a correct program without such a system, but experience tells me otherwise because I do it all the time.

I'm not against static typing, I'm against thinking it's the only approach that works; it isn't. When I said _you're not ready to be using a dynamic language_ I wasn't implying they're better, only that your mindset wasn't ready, it's a different style of programming and you can't do it thinking about types all the time. If a type system seems important to someone, they shouldn't be using a dynamic language in the first place and trying to _fix it_.

There are things I do in Smalltalk that I simply wouldn't or couldn't attempt in C# and I have to adjust my programming style when switching between the two. However, there are things I do in C# that I don't do in Smalltalk like overloading that take advantage of the type system more.

Overall, I find the Smalltalk experience superior _for me_ because of things like real meta-classes and #doesNotUnderstand: and the superior development environment that simply let me get more work done with less and simpler code and a runtime system that frees me from the compile/run/debug cycle.

</comment></comment></comment></comment></comment><comment><USER5> I've been writing Ruby for years now and only a very tiny portion of my bugs are caused by type errors. I don't see how this is useful in practice.

<comment><USER6> I've found similar systems to be very useful in certain situations, including: refactoring, rapidly changing code bases, and code that doesn't have enough unit tests.

Yes, all of these situations could be improved by having more unit tests, but systems like these have an extremely high bang-buck ratio. They're extremely cheap to put in, and they some bugs.

</comment></comment><comment><USER7> I'm not sure how useful this would really be in practice. It seems that it would only be useful to debug obscure bugs if it was used consistently everywhere. However, littering your code with these calls would make it a fair bit more dirty, for a very small reduction in debugging time (apparently - that's not event 100% clear... perhaps having to read all that extra code when looking for a bug will make it take longer anyway).

I'll pass on this one, myself. Ruby's best used by people who have become capable of not shooting their own feet without language safeguards.

<comment><USER8> There are situations where it's very useful. I've used similar modules for code doing financial calculations. Because Ruby has weakly typed numerics, it's quite easy to inadvertently coerce a value to Float. Once this happens you will start seeing, as you say, obscure bugs from floating point errors. The location where the bug manifests can be entirely different from the location in the code where the type coercion occurred. Placing type constraints on functions involved in these calculations seems quite warranted.

I wouldn't use this module on every function you write, and it doesn't seem like the author is advocating that. But strategically enforcing the expected types in critical portions of your codebase can be valuable.

<comment><USER9> It would be 'weak' typing if Ruby ran an integer routine on a raw mantissa|significand value. Ruby is effectively doing type-checks on every operation, and that can _never_ be 'weak'

What you're complaining about is that it has a numeric tower, but does not have anything like type-classes.

<comment><USER6> The problem is that ruby implicitly casts in a way that loses precision, exactly the opposite of what the author (may) desire. Call it whatever you want.

        2**100
        => 1267650600228229401496703205376
        > (2**100).class
        => Bignum
        > (2**100)*0.5
        => 6.33825300114115e+29
        > ((2**100)*0.5).class
        => Float</comment></comment></comment></comment>


A bug in Joe Biden's campaign app gave anyone access to millions of voter files - <AUTHOR> https://techcrunch.com/2020/09/14/biden-app-voter-files/ <comment><USER2> Glad it was found. These days it is risky to have information about who you are voting for be public.

<comment><USER3> Only if you vote Republican!

<comment><USER2> True, but that could change in the future :)

</comment></comment></comment><comment><USER4> Wonder what would have been the headline if it were Trump's campaign app</comment>


Don't Sign That Non-Disclosure Agreement Yet - <AUTHOR> https://shift.newco.co/dont-sign-that-non-disclosure-agreement-not-yet-anyway-27ef5557fd9a#.q4y4mlkri <comment><USER2> I'm not sure if this is good advice or not. I am most certainly not a lawyer.

I will say that when dealing with companies in a bankruptcy or wind down situation be very careful.

Often you'll find that their bankruptcy trustee will expect you to follow to the letter of the law the contract you signed while at the same time they'll use the shield of bankruptcy to their advantage to try and get out of their own duties.

I've seen this play out more than a few times. Usually with a small company providing a service to a larger one. When the small company goes under they'll still try to collect all revenue due from the larger company while telling the larger company that they are creditor 128 in line to collect what they are owed.

I think Joel Spolsky alluded to something similar, though much more dubious, where in the first dot com companies would sign contracts where it would be one company selling $200,000 of services to another, but in order to beef up the revenue of both companies they'd also do a "swap" of services so the contract would end up looking like A pays B $1,200,000 and B pays A $1,000,000.

So in theory things would net out to A paying B $200,000. However if A went bankrupt it would still try to collect the $1,000,000 owed to it by B but do their best to get a hair cut from anything they had to pay.

<comment><USER3> I personally don't think it's great advice - you're effectively working on the promise of a third party you don't know without any structure around deliverables, timing, payments etc. What if they turn around in 6 months time and say "Oh! We don't really need that. But no worries, we don't have a contract so we're all good."

Better advice IMO is for service providers to spend a little money up front and develop their own standard form contract that they can serve up at the beginning of any engagement. If the buyer insists on using their form (say, if they're a big company) then at least they have a template to compare it to and make sure they're covered in the areas that matter.

<comment><USER4> This advice seems to cover a corner case: If you might not be paid, don't put yourself under contractual obligation to complete the work. It opens up problems for both sides, though. I thought that proof of a signed contract would've been a given in this situation before any information would be shared and before the work would commence. It seems like a no-brainer.

The NDA itself? Well, if they aren't forcing you to sign that, I'm not so sure why you would.

<comment><USER5> Surly not being paid means the contact is frustrated

<comment><USER6> IANAL and this is not legal advice

But yes, generally the terms of a work-for-hire contract specify an exchange of money in return for the work

However, most NDAs are completely independent of getting paid. Thus the author's advice to sign the main contract but leave off the NDA.

<comment><USER7> AFAIK, work for hire is separate from being contracted as well. Unless things have changed in the last 10-20 years you can have a valid contract to spend time and deliver software without the copyright assignment that comes with WFH.

In fact, this was common practice for doing enterprise consulting to small businesses when I was doing it at the start of my career. You could frequently reuse layouts and components between jobs since it was mostly basic 4GL+RDB, and it was typical to have no work-for-hire clause at all or a very limited one excluding reusables; or to charge a higher price if the client insisted on the clause to cover redevelopment.

I believe this was also the model that early open source companies such as Cygnus (who I also worked for) was built on. Large companies paid us to port the toolchains to their systems, but I believe the copyright was retained by Cygnus (and presumably reassigned to the FSF).

If someone had work for hire in a separate agreement, and I was otherwise inclined to take the "wait until requested" route, I'd probably wait on returning it too. I don't think I'd sit on the contract that said I'd get paid though, and I'm sure they're usually combined. I just wouldn't point out the omission if I got a contract without one.

</comment></comment></comment></comment></comment></comment><comment><USER8> This isn't good advice in general - sure, in this situation you happened to have all the leverage because you were developing a core product of the company they needed to own to raise funding, but that's a corner case.

It's just as likely the situation be flipped and the client refuses to pay because there's no contract. The contract is there to protect both parties.

Starting work without a contract puts you at risk as a consultant - maybe the funds haven't been approved yet and the contract will never be approved, maybe the ultimate approver will disagree with the scope and you'll go down the wrong path with your day to day contact ...

Most companies hiring contractors are going to be larger than a handful of people and it's dangerous to assume you understand the internal dynamics as an outsider.

Just like a client will check that you can uphold your end of the contract by checking your references and qualifications, it's ok to ask a smaller client like a startup for assurances that they can actually pay.

<comment><USER9> I think both you and the author have valid points. If the contract is favorable to you, then you'll probably want to sign it. And pretty much all contracts should be favorable to both parties (if it isn't, then don't sign it until it is).

However an NDA isn't favorable to you on it's own. If they forget to make you sign it, then it's a slight net-positive to you. But normally you'll sign an NDA to get their business which is favorable to you and a reasonable exchange.

I think as a general sniff test, it's not a bad one. Both parties should be equally responsible and this is one way to perhaps demonstrate a lack of responsibility from the other party. Conversely, if you want someone else to sign your contract, you should follow up to make sure it happens.

<comment><USER8> I agree with you that often the consultant gets nothing out of the NDA (bar the case where the consultant is sharing a proprietary method). Larger consulting firms actually often include their own form of NDA in engagement letters forbidding the client from sharing work product with third parties without permission.

The NDA is typically separate from the actual engagement letter in my experience, and to your point I've actually worked on projects where we signed the engagement letter but "forgot" to sign the NDA and that piece fell through the cracks

We scrupulously acted as though we had though to prevent the reputational damage that would come from violating confidentiality - NDA or no NDA.

</comment></comment></comment><comment><USER10> There are far more problems than NDA's and IP ownership going on here.

Moreover - I don't think the failure to sign an NDA would change the nature or 'who owns what' for the most part (unless it governed paid work, which most NDA's don't - they are simply 'non disclosures' i.e. 'keep this a secret' type docs).

Finally - it's hard to imagine a contract that specifies that the code that consultants write is 'owned' by the company - when payments are not made.

A consultant could require that the code does not belong to the company until it's paid for, legally.

More pragmatically - all legalities aside - if a company is not paying for services rendered, it's easy enough to withhold the code.

If the company wants to move forward - they can pay for it. The last thing a startup wants to do is start a big legal process and go through courts to 'get access to their code'.

In the end all these problems are not due to legal documents, they are due to people not being paid for services as per their agreement.

<comment><USER11> I've seen a lot of contracts try to do exactly that—IP ownership is the company's regardless of outstanding bills. I refuse to sign those clauses, of course.

Most likely what would end up happening is that the startup wouldn't be able to close any new investment if they were in this situation.

</comment></comment><comment><USER12> In my experience, it's far simpler to have a standard contract where IP isn't owned by the customer until the project is paid in full.

NDAs are well and good, they make lawyers feel more comfortable. But, you can't "own" something until you "pay" for it. Two things, not related.

</comment><comment><USER13> I'm inclined to agree. I don't see any reason to sign an NDA unless it's actually required. If the other party doesn't care enough to validate, they're probably not using the NDA for its intended purpose anyway.

<comment><USER10> Though it's a good idea to not sign an NDA unless required - any company worth their salt will (very reasonably) ask you to sign and NDA if you're going to be working on their stuff.

</comment></comment><comment><USER14> I don't like the way they did it... That's not karma-positive. They should have insisted on signing the thing before starting, a contract has two parties.

I experienced first hand that situation. And all the anger that came out of that is simply too much for me. Moreover, if you trap someone like this, he might fight back with other parts of the contracts you have not read carefully, or even with innocuous mails or whatever their lawyers can find. And if you're like me, a coder-at-heart, believe me, you're out of your league with those guys...

</comment><comment><USER15> From the buyer's end, what's notable in both cases described here is that the customer asked the vendor to sign the NDA after having already divulged the project scope and details. You're doing it wrong!

The whole purpose of an NDA in these cases is to protect the proprietary information that is handed over by the buyer in the normal course of scoping and proposing a project. Karma and politeness aside, when you are out in the marketplace, you need to protect yourself.

</comment><comment><USER16> Five months of unpaid invoices? That's wild that they would allow it to go that far... if there is no contract in place and you've somehow stiffed me for 5 months, I'm shopping your source code to your leading competitors to recoup my cost.

</comment><comment><USER17> Or, put a clause into the NDA and WFH agreements that makes them unenforceable if you haven't been paid. Working without a contract is ill-advised.

<comment><USER18> I remember seeing advice to include a clause that makes their ownership of intellectual property contingent on paying you in full. It's easy to get them to agree to up front, because they intend on paying you (or at least want to look like they do), so it's irrelevant as long as you get paid. If you don't, however, it means you have actual leverage and their BATNA is getting owned in a lawsuit.

<comment><USER19> It's from: Mike Monteiro - "Fuck you pay me" talk.

Here's a link to the relevant bit in the video: [https://youtu.be/6h3RJhoqgK8?t=21m24s](https://youtu.be/6h3RJhoqgK8?t=21m24s)

I would however, recommend the whole vid.

</comment></comment></comment><comment><USER20> There's an angle to this that I appreciate spiritually - making sure your client is conscientious and committed - and an angle that is legally and ethically highly risky.

Instead of putting contracts in the drawer and setting yourself up for future legal peril (and dissection of any implied contracts you may have entered) figure out if your client is trustworthy and liquid early. If there's risk, structure contracts to manage the risk, such as a short-term engagement leading to a longer / higher-value contract that locks you in. If you can't agree that structure you probably shouldn't take the contract in any case.

If they don't pay the first bill, fire them like any good contract will allow. Don't wait five months.

</comment><comment><USER21> In certain states such as NY, oral agreements may be enforceable, so don't count on this strategy. [http://www.nisarlaw.com/blog/2013/july/litigating- breach-of-...](http://www.nisarlaw.com/blog/2013/july/litigating-breach-of- oral-contracts/)

(IANAL)

</comment><comment><USER22> A contract is there to protect both parties. Failure to negotiate a fair contract is only going to lead to a headache. This is terrible advise.

</comment><comment><USER23> It's also a gating mechanism for interviewees who don't complete their paperwork.

</comment><comment><USER24> I don't understand this. What does the NDA have to do with who owns the code?

A better plan is to get paid up front. At least partially.

</comment><comment><USER25> The main lesson here is to leave a company that doesn't pay you immediately. The rest of the lesson is only for the idiots who didn't do that like the author.

<comment><USER26> The problem is that most contractors will feel trapped by the sunk costs -- fallacy or not.

If you've put a month of work towards something, and they say "funding's coming through, give us a couple weeks for the first payment," you have two choices: keep working and have a _chance_ that you'll get paid, or stop working and be guaranteed you'll never be paid for that month you put in.

<comment><USER27> There's your first problem. You had a shitty contract that isn't paying you for billable hours.

If you quit paying me, or on net 30, you __will __pay for the work I 've done. And if you don't, I'll take your ass to court. "Fuck you, pay me."

Very relevant video: [https://www.youtube.com/watch?v=6h3RJhoqgK8](https://www.youtube.com/watch?v=6h3RJhoqgK8)</comment></comment></comment>