
Why do many math books have so much detail and so little enlightenment? (2010) - mathgenius
https://mathoverflow.net/questions/13089/why-do-so-many-textbooks-have-so-much-technical-detail-and-so-little-enlightenme
======
jessriedel
The top-rated answer is either defeatist, or just rationalization for the
sentiment "I had to go through this and figure out everything myself, so you
should too".

There is a _huge_ amount of information encoded in the choice of exactly how
to define thing, and which theorems people care about. This reflects a long
process of trial-and-error as the field was constructed. For a famous
philosophical treatise on this using the Euler characteristic as an example,
see "Proofs and Refutations” by Imre Lakatos

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

Part 1:
[https://math.berkeley.edu/~kpmann/Lakatos.pdf](https://math.berkeley.edu/~kpmann/Lakatos.pdf)

Most of that foundational information is lost when it's not written down
somewhere accessible; contrary to the answerer, only a small fraction is
reconstructed by students as they learn the subject.

It's a huge problem, it applies to physics textbooks too, and it doesn't have
to be this way. Unfortunately, the problem has been known for decades and
there's not much reason to expect things to change. (Lakatos wrote the above
in 1976.)

~~~
infinity0
> Most of that foundational information is lost when it's not written down
> somewhere accessible; contrary to the answerer, only a small fraction is
> reconstructed by students as they learn the subject.

From "A Mathematician's Apology", G. H. Hardy:

> Statesmen despise publicists, painters despise art-critics, and
> physiologists, physicists, or mathematicians have usually similar feelings:
> there is no scorn more profound, or on the whole more justifiable, than that
> of the men who make for the men who explain.

From another angle: when developing new theories or models, your thoughts are
all over the place and frankly it's _boring_ to go over your own crappy notes
afterwards and try to reconstruct them in a way that others can understand.
And much of the time you forget _exactly_ what happened along the way as well,
so any story you reconstruct is going to have some hindsight bias, which
defeats the purpose of trying to "teach the story".

Really, from the first answer:

> Based on my own experience as both a student and a teacher, I have come to
> the conclusion that the best way to learn is through "guided struggle".

This is the only way to "properly" learn mathematics or science. Anything else
is only making you _think_ you've learnt something.

~~~
impendia
> mathematicians have usually similar feelings: there is no scorn more
> profound, or on the whole more justifiable, than that of the men who make
> for the men who explain.

Yes, Hardy was a great mathematician and he did say this --- but most
mathematicians have tremendous respect for peers who strive for clear
exposition in their lectures, their papers, and (if they write them) their
books.

I am a professional mathematician, and Hardy's attitude is one I have _never_
heard expressed by any of my peers.

"A Mathematician's Apology" is a fascinating read, but his description of
mathematicians' attitudes is certainly not accurate today.

It indeed can be boring to reconstruct your thoughts in a way so that others
can understand -- but many of us make the effort anyway, and doing so often
leads to new insights.

~~~
infinity0
The full paragraph (in fact, the very first paragraph of the essay) reads:

> It is a melancholy experience for a professional mathematician to find
> himself writing about mathematics. The function of a mathematician is to do
> something, to prove new theorems, to add to mathematics, and not to talk
> about what he or other mathematicians have done. Statesmen despise
> publicists, painters despise art-critics, and physiologists, physicists, or
> mathematicians have usually similar feelings: there is no scorn more
> profound, or on the whole more justifiable, than that of the men who make
> for the men who explain. Exposition, criticism, appreciation, is work for
> second-rate minds.

I interpreted "men who explain" not as mathematicians that can explain their
work well, but as people who try to explain mathematics in a "lay" way to
cater for a large audience, whose explanation can very often become
inaccurate, non-mathematical or just downright false, yet still get public
credit for seeming to know the field very well, despite these inaccuracies,
and even though they are not directly pushing the advancement of the field
itself.

It's of course a good thing to try to reconstruct your own thoughts, but I
wouldn't say it's unreasonable for a mathematician to _omit_ doing that. Could
you go into more detail on the examples you mention, where doing so led to new
insights?

~~~
impendia
> Could you go into more detail on the examples you mention, where doing so
> led to new insights?

Good question. It's a bit hard to do so (especially without going into mind-
numbing technical detail) -- in math you never quite know where insights
really come from. "Fortune prepares the prepared mind."

But generally speaking, I would say that good exposition gets you thinking
about: Why does the technique work? What is the key insight? What are its
limitations? And if you think about such questions, you naturally get a better
sense of for which other questions your techniques are also likely to work.

------
BucketSort
Because they are written by mathematicians. In my case, when I have learned a
mathematical topic, the intuition becomes obvious and the derivations/proofs
seem to be much more important for gaining a complete understanding. I have
gone up against texts with complete bewilderment, only to come back after
gaining the intuition and found the extensions of the core premises and proofs
provided by the text to be highly enlightening.

Great math teachers understand the need to teach intuition. He wasn't a math
teacher, but I think Richard Feynman is the pinnacle of this. See [1] to see
how he expresses intuition about physics, and his Red Books[2] for how he
teaches mathematical physics with all the qualities I believe makes a great
maths text for students.

Also, there's a linear algebra MOOC which also teaches great intuition before
delving into proofs and heavy detail [3]. I mention these examples because
they are exemplars of this idea of teaching intuition.

[1]
[https://www.youtube.com/watch?v=4zZbX_9ru9U](https://www.youtube.com/watch?v=4zZbX_9ru9U)

[2] [https://www.amazon.com/Feynman-Lectures-Physics-Vol-
Mechanic...](https://www.amazon.com/Feynman-Lectures-Physics-Vol-
Mechanics/dp/0201021161/ref=sr_1_2?ie=UTF8&qid=1494813362&sr=8-2&keywords=lectures+on+physics)

[3][https://www.edx.org/course/linear-algebra-foundations-
fronti...](https://www.edx.org/course/linear-algebra-foundations-frontiers-
utaustinx-ut-5-05x)

~~~
mathgenius
> Richard Feynman is the pinnacle of this

There really needs to be a version of the Feynman lectures for mathematics.

Although, this is what Arnol'd has to say [1]:

"Mathematics is a part of physics. Physics is an experimental science, a part
of natural science. Mathematics is the part of physics where experiments are
cheap... In the middle of the twentieth century it was attempted to divide
physics and mathematics. The consequences turned out to be catastrophic. Whole
generations of mathematicians grew up without knowing half of their science
and, of course, in total ignorance of any other sciences."

[1] [https://www.uni-
muenster.de/Physik.TP/~munsteg/arnold.html](https://www.uni-
muenster.de/Physik.TP/~munsteg/arnold.html)

~~~
cottonseed
> There really needs to be a version of the Feynman lectures for mathematics.

I asked the question on math.SE:

[https://math.stackexchange.com/questions/62190/mathematical-...](https://math.stackexchange.com/questions/62190/mathematical-
equivalent-of-feynmans-lectures-on-physics)

~~~
setq
Feynman learned mathematics from a series of self teaching books published in
the 1940's suffixed "...for the Practical Man" and prefixed with Arithmetic,
Algebra and Calculus. I have the full set and this is a rather good solution
to the problem. They teach you insight and how to think about things as well
as the mechanical aspects. This is IMHO a well solved problem if you don't
mind skipping more modern abstractions such as limits.

From there he was given a calculus book, the title of which I cannot remember.
I never got that far.

I suspect you have to at least follow the same path to have the same
intuition.

~~~
dagw
I sometimes get the feeling that we seem to have taken a huge step backwards
in math books over the past 50 years. Back when I was in college and studying
multivariate calculus I happened to find a small, ~100 page, book called
something like "Introduction to Multivariate Calculus" from the 50s in a used
book store. This tiny books not only covered basically the whole curriculum of
my course, but did it in much greater clarity then the 500+ page that was our
textbook. I can basically thank that book for me passing that course. I find
on the whole that especially introductory mathbooks have gotten harder to
follow and less clear (and a lot longer) over the past few decades.

~~~
setq
Completely agree.

I've taken the liberty of taking a quick snap of a random page in "Arithmetic
for the Practical Man" to include below for those poor people poisoned by
modern textbooks:

[http://i.imgur.com/Bg9OiiK.jpg](http://i.imgur.com/Bg9OiiK.jpg) (926KiB)

I see horrible modern behemoths of over a 1000 pages that leave you dazed,
confused and full of facts but nowhere to go with them. EE textbooks are even
worse on this front than your average mathematics text book. I've seen one
proudly promoting over 1500 pages and 1000 illustrations, but doesn't even get
as far as an opamp or discuss anything at system level.

~~~
novalis78
bought the series as well, love it. It's my daughter's favorite math series.
One interesting thing I noticed in this regard is textbooks from the 30-60s
have way more textual descriptions. They seem to spend more time looking at
the problem or concept in a literary way and that might have helped to build a
better understanding for the student.

------
teddyh
See also “ _A Mathematician’s Lament_ ”, written by Paul Lockhart in 2002:

[http://www.maa.org/external_archive/devlin/devlin_03_08.html](http://www.maa.org/external_archive/devlin/devlin_03_08.html)

“ _Sadly, our present system of mathematics education is precisely this kind
of nightmare. In fact, if I had to design a mechanism for the express purpose
of_ destroying _a child’s natural curiosity and love of pattern-making, I
couldn’t possibly do as good a job as is currently being done— I simply
wouldn’t have the imagination to come up with the kind of senseless, soul-
crushing ideas that constitute contemporary mathematics education._ ”

~~~
brutus1213
I took a minor in Math because I enjoyed some aspect of it but completely
agree with the quote. All my math courses were taught in a vacuum or worse,
taking problems that bore no connection to situations I cared about. Over the
years, as I explored various hobbies, I found mathematical ideas having
application - that's when I truly made an effort to understand concepts fully.
For my kid, I plan to introduce math concepts in the context of these hobbies
.. if any one cares .. these are astronomy and radio.

------
cft
"closed as no longer relevant ", I find that is a growing problem with
StackOverflow. My colleagues and I personally asked several relevant questions
(like this one, that has many upvotes on HN), that were shut down or deleted
by StackOverflow heavy-handed mods as "off topic" , "not relevant" etc. This
made me give up on contributing and treat it as a read-only resource.

~~~
sanderjd
I'm very curious about this: is there a reason the reductionists seem to win
in communities like this? Wikipedia has a similar culture. Are there systemic
forces that point this direction, or is it just an accident of the history of
the specific people involved?

~~~
umanwizard
It's worth noting that SE and Wikipedia are two of the most valuable reference
resources human civilization has produced, ever in history. Maybe the
reductionism contributes to their high level of signal.

~~~
reitanqild
My problem is that it feels like they could have been much more useful.

Annoyingly often it is also the most useful questions that are closed while
things I consider trivia style/karma-farming operations like: "what is the
reason for x" seems to be totally OK.

I too find those trivia questions and their answers interesting but IMO they
are a distraction.

~~~
brohee
I used to think like you, then I saw Quora become an useless "stupid questions
answered by smart people" site...

------
fpoling
There are absolutely non-boring mathematical books by Russian authors. In
addition to already mentioned "Mathematics: Its Content, Methods and Meaning"
by by A. D. Aleksandrov, A. N. Kolmogorov, M. A. Lavrentiev I would add
"Elements Of Applied Mathematics" by YA. B. Zeldovich, A. D. Myskis [1]. The
latter is really good introduction into math when one needs to apply it in
various settings.

[1]
[https://archive.org/details/ZeldovichMyskisElementsOfApplied...](https://archive.org/details/ZeldovichMyskisElementsOfAppliedMathematics)

~~~
inlineint
And also there is a more introductory book by YA. B. Zeldovich and I. M.
Yaglom "Higher Mathematics for Beginners" [1] that is a fun to read book about
calculus.

[1]
[https://archive.org/details/ZeldovichYaglomHigherMathematics](https://archive.org/details/ZeldovichYaglomHigherMathematics)
\- for some reason the book at archive.org has extension .pdf , but in fact it
is a djvu document, so it has to be opened with DjView instead of a PDF
viewer.

------
Tomminn
It's totally cultural. The culture comes with some costs, and some benefits.

In physics, there are so many times where we present the same mathematical
ideas in a manner that's way more ergonomic for the minds we're talking to--
other physicists.

Inexperienced mathematicians tend to see these presentations and are kind of
gobsmacked, "why did no-one tell me it was that simple and concrete?"
Experienced mathematicians tend to see these presentations and cringe, "don't
they understand it's not that simple and concrete? For instance, look at this
pathological example here that contradicts everything they just said."

The slick presentations are great if you're a physicist or anyone just wanting
to _use_ the ideas. And they're great if you're an inexperienced mathematician
trying to get your bearings as fast as possible. But once you're a research
mathematician, trying to _build new ideas_ , too many slick presentations of
ideas just creates groupthink. You want as many people to generate their own
mental pictures as possible.

That said, few people studying mathematics go on to be research
mathematicians. The mathematics culture should be much, much friendlier to
people whose endgame is not being a math prof. Apathy toward those whose
ambitions lie outside the ivory tower is a problem endemic to most academic
subcultures.

Finally, when reading anything generated by academia, remember _most of it is
crap_. Academics are fired if they don't make enough noise. This is truer than
you think, even taking into account metrics like "impact". You can make a lot
of "impact" just by making enough noise. And you generally can't make "impact"
on a short timescale without making enough noise. Once your name shows up
enough in a field, you'll get known as "a name", and start being cited in that
field. Even when your work is drivel. If your name only shows up a couple of
time in a field-- unless your work incredibly well written and you get a good
dose of luck-- it'll take years before it gets uncovered and appreciated, if
it ever does.

Think of how much more attention you pay to what someone like maxxxxxxxx says
here. Sure. He's good. But he's also familiar. It's primarily his familiarity,
more than his quality, that makes you feel like he's one of "names" in this
little subfield of the internet called hacker news.

~~~
jimhefferon
> culture

Yes, I think you are right. I offer a free Linear Algebra book that appears on
the first page of a Google search. The book's approach is to give a lot of
explanation and motivation, so I often get emails from folks about this topic.
From students often the mails say something like, "I couldn't understand my
prof but by using your book as a supplement .." while from the prof I get
(much less often) "way too chatty."

So I agree that a lot of it is a question of culture and taste.

On my first day in grad school a prof who I admire a great deal told me what
he liked best about Differential Equations is that you don't have to say how
you found the answer. You just state the answer and verify it satisfies the
equation. I think that's the taste of people who enter the field.

(I also think that is the taste of the moderators of MO, which is why
questions like this have been closed over time.)

~~~
wikibob
Can you link your book? Checked your profile and didn't see a way to find it.

~~~
jimhefferon
Sure. I'm a little shy about posting it around here because I don't want to
seem to be spamming.
[http://joshua.smcvt.edu/linearalgebra](http://joshua.smcvt.edu/linearalgebra)

~~~
scott_s
Don't be. The first thing I did when reading your above comment was to do the
Google search. I should have scrolled down!

I'm browsing through this, and it's clear to me this is a _textbook_. In that
it easily looks like it could be the textbook of record for college courses.
This is an enormous amount of work. Am I correct in assuming it grew out of
your lectures notes? What lead you to make this a freely available textbook,
instead of going the "normal" route of going through a publisher and getting
royalties?

~~~
jimhefferon
Yes, it is a text. As the linked-to page says, it has been used in hundreds of
classes at many schools as well as by thousands of individuals for independent
study.

> Am I correct in assuming it grew out of your lectures notes?

No, really I wrote it intentionally not organically. I used Strang's book in a
course a couple of times and while that is a very fine book, the students I
had in front of me had trouble with it (and anyway I wanted to cover a
somewhat different set of topics). I looked around some more but basically I
couldn't find a text that fit.

> What lead you to make this a freely available textbook, instead of going the
> "normal" route of going through a publisher and getting royalties?

I wrote it using LaTeX, on Linux, using emacs. It seemed natural.

I do get some money, from Amazon sales, because it would be stupid to not
round the price up. (But in general, everyone tells you that unless you write
a very popular text for a very big audience, you are not going to see much
money. You need to get your pleasure from the creative accomplishment.)

------
jansho
Try Roger Penrose's "The Road to Reality."

He takes the approach of assuming that his readers can range from absolute
beginners to mathematicians, and that if you prefer, you can skip the
equations and the exercises.

But if you attempt to understand them, then your picture of the Universe will
become richer that no other pop science book can promise.

It's an enticing thought, and that and his gentle prose are just about his
only tricks to push his readers through his enormous tome.

I haven't finished it yet but it does feel rewarding that much of the maths
that I've come across (Alevels and engineering degree) are there, laid out in
a new framework of meaning, the Universe.

P.S. There's also an eBook version, and an online resource that gives
solutions to the exercises.

~~~
anatoly
My advice is to not try Penrose's book. The vast majority of its contents will
be utterly incomprehensible to someone without a PhD level background in
physics.

Technically it is self-contained and nothing beyond high school knowledge is
needed to understand it; but while technically true, in reality it's a cruel
deceit. If you try to learn it without advanced training in physics and math,
you'll run into limitations related to mathematical maturity
([https://en.wikipedia.org/wiki/Mathematical_maturity](https://en.wikipedia.org/wiki/Mathematical_maturity))
very quickly, within the space of the first few chapters.

The idea of this book seems noble and uplifting, but it cannot be done in this
fashion. It doesn't matter that every theorem and assumption are clearly
stated and follow each other in an orderly sequence. There's a huge number of
new ideas, mathematical and physical, which require proper acquaintance to
settle in your mind, not the 1-2 pages Penrose is able to give each of them.
If someone is serious about learning physics to that level "properly" and is
willing to invest the time and effort, they're much, much better off working
through conventional college-level (and later grad-level) textbooks in
particular subjects, taking care of math prerequisites before and during such
study. That's very very hard to do, but is in fact possible, whereas studying
solely from Penrose's book, I think, is not. It functions, sadly, as a sort of
trap for impressionable bright people very eager for advanced knowledge - they
will try to struggle through it, inevitably give up rather early on, and blame
themselves.

~~~
jansho
> It functions, sadly, as a sort of trap for impressionable bright people very
> eager for advanced knowledge

Or perhaps people who assume that it's a good all-in-one solution to get a
glimpse of understanding the Universe. For me personally, I have no wish to be
mathematically fluent now. I admit that I can't imagine committing wholly to
the studies of maths and physics for more than two years - this book seemed
like a Magic Bullet.

My plan is to read it very slowly, perhaps over a decade. My mind is on other
projects for now, but if I have this quietly stewing at the back of my mind,
maybe one day I can be braver to make the jump and study maths and physics
seriously.

At least, that's the plan. A retirement amongst books - I thought that's
appropriate.

Sigh, I do believe you though. Have you read this book to dispute Penrose's
claim that the less mathematically fluent can gain some useful insights?

------
Animats
Mathematics traditionally has a macho ethos. This goes all the way back to
Euclid, and his "Let no one ignorant of geometry enter" sign. The training
process primarily involves solving puzzle-like problems. Cambridge University
still has Wranglers and Senior Wranglers [1], chosen for success at solving
puzzle-like problems, not originality. (Hardy once wrote that this set English
mathematics back a hundred years.)

This history infects mathematics books.

The other traditional problem with mathematics is terse and obscure notation.
There are many implicit assumptions embedded in published mathematical papers
and books. This is not helpful. It's like reading code snippets without the
declarations.

[1]
[https://en.wikipedia.org/wiki/Wrangler_(University_of_Cambri...](https://en.wikipedia.org/wiki/Wrangler_\(University_of_Cambridge\))

~~~
xyzzyz
_The other traditional problem with mathematics is terse and obscure
notation._

It's only a problem if you are unfamiliar with the subject area, and if you
are, you have very little chance to understand the paper or book anyway.
Mathematics is just difficult, way more difficult than most other stuff people
might be doing.

Here's an example: consider this classical paper[1], "Vector Bundles Over An
Elliptic Curve" by M. Atiyah. The author is a well known and regarded
mathematician, and the paper itself has around 1000 citations. Sections 1. and
2., "Generalities" and "Theorems A and B", just recall the basic notions and
theorems that are absolutely necessary to have any grasp whatsoever as to what
is going on in the paper.

If you know nothing about algebraic geometry, the classical way to learn these
is Robin Hartshorne's famous textbook "Algebraic Geometry". It is famous for
being both good, self-contained to a large degree, and having very well chosen
exercises, but also for being quite terse and often difficult to follow.
Here's an Amazon link[2]. You can look at the table of contents. To really
fully understand these two sections from Atiyah's paper, you need to have very
good understanding of Chapter 2. "Schemes", and at least first 5-6 sections of
Chapter 3. "Cohomology". This is 200 pages of pretty terse mathematics. At a
fast understanding pace of 4 pages a day, it will take you two months to even
have some basic toolset to understand the Atiyah's paper.

But, if you try to understand the Harthshorne's textbook, you'll quickly find
out that it also has some prerequisites of its own. Also, the "4 pages a day"
pace is only possible if you've already spent 2-3 years learning how to learn
mathematics.

I encourage anyone to try to understand even first 2-3 sentences of the
"Generalities" section. Google and Wikipedia the unfamiliar terms, you can
also try to look it up in Harthorne's textbook, or Vakil's lecture notes, or
any other source. The notions used in these first 2-3 sentences are basic to
anybody working in the field, and yet one needs to spend hours to fully
understand these when starting from scratch.

Compare this to other famous paper from other field, "The Market for Lemons"
by G. Akerlof[3]. This is also a very famous paper by a well regarded
economist, who received a Nobel Memorial Prize In Economic Sciences for it. It
is a much easier read, precisely because the economic sciences do not operate
on nearly the same level of complexity as mathematics. Once you know what are
some common sense notions like, supply, demand, utility etc., and some very
basic calculus, you can easily follow the argument without too much training.

My point here is that it's not that it's difficult to read mathematics just
because it uses terse and obscure notation. It all is just genuinely difficult
and complex, and it is impossible to invent better notation that will transfer
days and weeks worth of understanding straight to the reader's brain. I would
love it to be the case, but then it would cease to be as fun and rewarding to
really understand.

[1] -
[https://math.berkeley.edu/~nadler/atiyah.classification.pdf](https://math.berkeley.edu/~nadler/atiyah.classification.pdf)
[2] - [https://www.amazon.com/Algebraic-Geometry-Graduate-Texts-
Mat...](https://www.amazon.com/Algebraic-Geometry-Graduate-Texts-
Mathematics/dp/0387902449) [3] -
[https://www.iei.liu.se/nek/730g83/artiklar/1.328833/AkerlofM...](https://www.iei.liu.se/nek/730g83/artiklar/1.328833/AkerlofMarketforLemons.pdf)

~~~
sitkack
> but then it would cease to be as fun and rewarding to really understand

Mathematics is fun to understand because it is [artificially] hard to
understand?

~~~
xyzzyz
No, it is fun and rewarding because it is genuinely hard to understand. Once
you really understand it, it tends to become more obvious in hindsight, but
good luck getting your understanding across to someone else who hasn't spent
as much time thinking about this as you.

------
eecc
Back when I was in Uni I flunked Calculus II. The following year I switched
Uni and - somewhat fortunately - I re-followed the same class.

I say fortunately because during my first round at Calculus II I couldn't
fathom the slightest underlying motivation for all the statements and proofs
that were regurgitated during class. I had no bearing - I nearly panicked with
the Cauchy Problem - and was doubting whether or not I was cut for Engineering
at all.

The following year the other Prof took a digression and for two weeks laid out
Inf-dimentional spaces, Banach spaces, functionals, contractions, fixed points
and so on. Then one morning, over the course of 2 hours he plugs in
differential equations, the Cauchy problem and deals with it with such
elegance, clarity and insight that I can still recollect the broad strokes.

I had first hand proof of the blessing and the curse of mathematics...

~~~
eecc
Right, the second prof's name was Francesco Saverio De Blasi, he passed away
in 2012. He was a terror to students but I appreciate the hours he spent
teaching us the basics with rare depth

------
sfRattan
I've historically had the opposite problem. I find attempts in both science
and mathematics textbooks to provide some sort of real world context to be
distracting and wasteful. I remember that impression going all the way back to
high school, but the most recent memory comes from early in college. My
discrete math book had some chapter that started with a page and a half about
volcanoes.

Volcanoes.

 _Why are you wasting my precious time with this nonsense before getting to
the meat? There are other things I need to read and study. There are problems
I need to use these ideas to solve... and not only the ones in the textbook._

But then, I can also recognize that such winding introductions to a subject or
an idea might be helpful to people who "get bored" as the author describes.
Though I suspect the remedy might be to acquire and deliberately practice
study skills. It would be nice if publishers sold versions of their textbooks
both with and without what the individual posing the original question would
identify as "motivation." I tend to think of it as fatty prose.

~~~
santaclaus
Half-assed physical analogs can be a drag, especially when the analogy breaks
down after any bit of scrutiny. Geometric intuition, on the other hand, I
often find worth the weight of a thousand words. There have been times I
haven't been able to make my way through a dense piece of mathematical text,
only to pop open another book on the same topic to find a single picture that
makes all of the pieces click.

------
ivan_ah
The conversation is about very advanced math topics (advanced undergraduate or
graduate level). At some point in the levels of abstraction it becomes hard to
show concrete applications of the ideas, or rather the applications of math is
to do ever more advanced math.

I find more deplorable the fact that even basic math topics are often covered
in the same dry way, without discussing practical applications or introducing
topics through real-world scenarios. Many math books take the attitude "You
have to know this, because I say so." Whenever I write about math, I try to
start with a concrete example or a useful application of the theoretical
result—it's always possible to come up with something for most of first year
stuff. Seriously, you'd be surprised how much better reading UX is if you
start each chapter/section with a motivating example.

~~~
jordigh
I find that almost all books I read do discuss "applications". No mathematics
is an island. But as you say, the problem is that a lot of those applications
don't really count, because the domain of the application is as foreign as the
original concept.

For example, knowing that the snake lemma, a purely categorical statement, is
most useful in homological algebra (such as, for example, simplicial or
singular homology), is utterly useless if you don't already have an interest
in algebraic topology. There really is almost no other motivation for the
snake lemma, so now we're faced with the problem of trying to convince you
that it's interesting by trying to convince you that algebraic topology is
interesting. It can be done, and maybe we'll eventually bottom out in
something like financial statements or bridge-building, or another topic that
is widely recognised as "useful" and very far-removed from the snake lemma.
Either way, it will be a long and arduous path, and I hardly think
mathematicians can be blamed for this or be dismissed as elitists for the
inherent difficulties of the subject.

But even for "first year stuff", the applications are kind of pointless. Do
you really want to learn calculus because of physics? That's the most obvious
and most historical application, but calculus is so foundational that you
might as well motivate addition of real numbers by saying that numbers are
added in physics too. More likely for the HN crowd, you want to learn calculus
because you want to know how a neural network's backprop algorithm works, but
how is the first year teacher going to anticipate that this is _your_
particular interest in calculus?

At some point, I think there has to be a little "trust me, this is useful" and
you just struggle through the subject until you can see on your own, after the
fact, what the struggle was about. First wax on, wax off, Daniel-san. Then you
will learn how you really were learning how to block karate blows.

------
tps5
People always say that math students don't learn about applications of math.

This was never the case for me. When I learned trig ratios, I always
understood some basic things that trig ratios could be used for. The teacher
always introduced some applications, we always had a lot of word problems, and
I could fill in the gaps myself.

Same for calculus. When I learned calculus, I always understood some things
that calculus could be used for.

So I understood how those things could be applied to general, everyday sorts
of problems. What was missing, though, was that I had nothing to which I could
apply those techniques, besides homework.

Learning math (and reading STEM papers) has become easier for me since I now
have actual problems to solve. Don't get me wrong: I'm not solving
particularly challenging problems or using particularly advanced math. Nothing
that tens of thousands of people haven't done before me. But I do need to
understand the problems, solutions, and some of the context in order to
successfully implement them. This provides a motivation that was always
missing before.

I suspect this general narrative is true for a lot of people: that having an
actual problem to solve is almost necessary to get a student to really learn
the material, instead of just coasting along for a grade.

~~~
jacobolus
High school trigonometry and introductory differential & integral calculus are
not the kind of books being described in this discussion.

The example in the original post is books about group theory (or the group
theory sections of abstract algebra books more generally). I can attest that
this subject is very rarely described in textbooks with clear examples shown
before definitions and theorems; usually the presentation is entirely
abstract, following a pure definition–theorem–proof kind of structure. But
many other areas of pure mathematics at the undergraduate level and above are
presented in a similar fashion.

(I recommend Nathan Carter’s book _Visual Group Theory_ for a lovely counter-
example to the prevailing trend, which starts with the concrete, and is very
accessible.
[http://web.bentley.edu/empl/c/ncarter/vgt/](http://web.bentley.edu/empl/c/ncarter/vgt/))

~~~
ianai
We used to "run through" books like that. Their reasoning was to prove a
theorem you only need the definitions/axioms. They really wanted us to be able
to grasp the truths of a logical system from just its theorems and
definitions. It was horrifically difficult. (Not all professors taught that
way there.)

I feel that a lot of blame lies at modern academias curriculums. They feel
every student needs to graduate in X number of years with a pretty long list
of courses. It leaves little time for students who need or want more time with
topics.

------
alistproducer2
On this topic I recommend the "learn X in 20 minutes a day" series of math
books for folks trying to get started in subjects they've had difficulty with
in the past. I always struggled with Calculus until that book. The math is
taught almost entirely by visuals and intuition hints. I came away
_understanding_ Calc, not just how to perform the steps. It helped me divine
the purpose of calculus, not just the process. I've used them for Geometry and
stats to similar effect. Highly recommend for anyone who share the sentiments
of the OP.

~~~
sarang23592
Could you share any links where I can find these books. I tried google but
couldn't find them.

~~~
theoh
Must be this publisher, Learning Express:
[https://www.goodreads.com/author/list/24061.LearningExpress](https://www.goodreads.com/author/list/24061.LearningExpress)

~~~
alistproducer2
Yes, this is the publisher. Thanks. I got the titles slightly wrong on my oc.

------
dzdt
I think this, as much of higher mathematics, will change soon.

Today's technology in natural language processing is reaching the point where
it will be possible to marry a natural language processing system to an
automated theorem prover and have it generate formally verified proofs from
math prose proofs.

Once this technology can readily process the textbooks making up the PhD
curriculum, I think there will be a culture shift. Quickly there will be a new
standard that math results should be formally verified. The hallmark of math,
after all, is that it can be proven correct!

But with an increased role for computers will come an increased appreciation
for the things that only humans can provide. Motivation and explication will
be more valued when the technical aspects of theorem-proving are automated.

~~~
xyzzyz
If what you are saying is indeed going to happen, then the "problem" will
become even worse. The formally verified proofs tend to be much more
unintelligible than the human generated ones, and when they stop being so, the
humans will become deprecated in general.

Practically speaking though, working mathematicians do not care that much
about formally verified proofs. Working mathematicians are more interested in
insight and understanding, and not necessarily in being completely sure of
every detail. Formally and automatically verified proofs are much better
suited for programming, as the automatic verification of the correctness of
the program is after all _the_ best regression test.

So, while interesting in principle, I doubt formal methods will change much in
how we do mathematics. Hopefully they'll change how we do software engineering
though.

~~~
skybrian
Perhaps it would mean that theorems are sometimes known to be true or false
before anyone understands why. Digging through automatically generated proofs
looking for interesting insights seems like a rather different experience than
groping in the dark, not knowing whether a proof is possible?

~~~
xyzzyz
If you have a statement that humans doesn't know how to prove, finding a proof
via automatically generated proof is kinda like trying to decrypt RSA by
factoring the key. In both cases, you're looking for a specific key in the
search space is extremely large. You can put some insights into the tool that
search for the solution, from simpler ones (e.g. using fast multiplication
algorithm to verify the candidate quicker), or more sophisticated ones (e.g.
using generalized number field sieve instead of trial division), but in the
end, they don't help you much in practice -- the search space is still too
large to expect to find a key in the lifetime.

~~~
skybrian
It's an interesting analogy but I think it proves too much. You could argue
that computers will never win at Chess or Go because the search space is too
large, and look what happened.

Although it's not proven, we have fairly good reason to believe there are no
sufficiently efficient shortcuts for factoring large prime numbers, while
there are shortcuts for proving many difficult mathematical theorems. After
all, humans can do one but not the other.

~~~
xyzzyz
You make a good point. I agree that the analogy is not perfect, and that if
you assume that breaking RSA is computationally hard for some intrinsic
reasons[1], then the theorem proving is more like chess and go, rather than
RSA. However, theorem proving is still much more difficult than chess and go,
if you consider time spent on a theorem vs. on a single game, and on the
number of good mathematicians vs. the number of good chess/go players. I think
we'll have human-level theorem proving solved by machines at some point in
future, though not very soon. Either way, humans will be well deprecated by
then.

[1] - Practically speaking though, the biggest reason we believe that
factoring is hard is that we haven't really figured out how to do this, so our
belief that it's hard is really build upon our feeling on hardness of theorem
proving. :) I think we have more intrinsic reasons to believe than P != NP
than that factoring is hard.

------
wmnwmn
I've wondered the same thing. Moreover, math books tend to prove the most
general case of every theorem first, rather than work up with the special
cases which were the reason anyone thought about the theorem to begin with. It
is strangely possible to learn how to prove quite abstract and difficult
theorems without actually learning much about what the theorems mean. In the
process of doing this one's ability to really think about mathematics or
formulate new questions worth asking, is at best not developed and at worst
stunted.

~~~
tome
> math books tend to prove the most general case of every theorem first

If only! Many times during my studies I was hoping that someone had proved a
result I needed, only to find textbooks that proved a slightly more special-
cased version that wasn't enough for my uses.

------
Naa4
The first time I really grasped the very basic concepts of linear algebra
instead of just being able to calculate things like eigenvalues was after
watching this series by 3blue1brown:

[https://www.youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2x...](https://www.youtube.com/playlist?list=PLZHQObOWTQDPD3MizzM2xVFitgF8hE_ab)

There is a series on calculus as well. It is honestly beautiful.

~~~
jgalt212
I concur. The calculus series is amazing.

------
cf
I feel when it comes to motivation in math, I just want to know why people got
so excited about a particular theorem in the first place. I'm ok with the
answer "before this theorem we assumed all these different things we proved in
similar ways were different. Now we know about their commonality and it allows
us to borrow mathematical machinery and use it here".

For example, take something like measure theory. A reasonable motivation for
measure theory to me is remembering your introductory probability class how
you had to learn a probability mass function for discrete spaces and a
probability density function for continuous spaces. Now these two ideas are
obviously nearly the same idea. I mean the notation used is a pretty big hint.
But you need measure theory to have the right concepts to describe how they
are the same.

Where are all those kinds of motivation for things like topology and
cohomology?

~~~
drostie
I asked the ##math chat room on Freenode about cohomology recently, more
precisely I expressed that it was for me the scariest math-word-that-I-
don't-know-yet, and I received the explanation "it isn't that scary once you
get used to it; it's just a way to repair exactness of sequences." Maybe that
helps?

For topology, I feel like there's a sort of meeting-of-two-different-things;
one starts with being very frustrated with the delta-epsilon-definition of
"limit" and its one-dimensional nature, and the limit-definition of
"continuous" and its clumsiness. The other starts from wanting to play with
spheres and Möbius strips and knots and the like. When you're playing with
these shapes a bijective mapping between two surfaces is not a fine-grained-
enough idea because it is not continuous; adding continuity gives
"homeomorphisms" which also aren't a fine-grained-enough idea because they do
not make reference to the space an object is embedded in; wrap a torus about
itself in a pretzel knot and you have something which is homeomorphic to a
torus but in 3D you can't get there without tearing part of the surface
through the other one, but in 4D you can. So finally we come to the idea of an
isotopy, which bumps "continuous" to the next level by saying "Just like you
can have a continuous path of points in space, you can have a continuous path
of homeomorphisms from one to another," and that's where the pretzel knot
becomes finally distinct from the torus in 3D, there is no continuous path
from the homeomorphism of the pretzel knot to the torus, to the identity
homeomorphism of the torus to itself. Or something like that. So this path is
then an "isotopy" and then certain things are nicely isotopy-invariant and so
forth.

~~~
cf
The topology explanation is about what I had in mind for motivation. I think
to appreciate cohomology, I need appreciate what problems in homology it makes
easy to solve. To appreciate that I need have the vocabulary of algebraic
topology.

One way to maybe then to describe homology is it gives you way to take about
shapes and surfaces in the language of algebra.

------
wslh
In the top answer one of the last paragraph sounds like the real answer:

> When I was a graduate student, we had a wonderful working seminar on Sunday
> mornings with bagels and cream cheese, where I learned a lot about
> differential geometry and Lie groups with my classmates.

At the end, the students needed context and enlightment. We cannot
underestimate other dimensions of the learning experience.

------
gjulianm
Honestly, every time that a discussion on mathematics comes up in HN I feel
the same way: people seem to think that mathematicians are some kind of
elitist people that don't know how to explain concepts, and that mathematics
would be like coding (note: projecting everything into the tech world is not
the best way to understand the world) if it weren't because mathematicians
don't explain things well. But the reality is way different:

* We know that teaching mathematics is difficult. But, contrary to what most people think, there is no magic pill to solve it. Motivation and intuition are important, yes, but so are definitions and formality. Also, even when giving them to the students, they might not be useful: sometimes each person needs a different motivation of a concept, sometimes the intuition relies on more advanced concepts... Furthermore, things don't usually click the first time you are exposed to them, but only after you have worked with them for some time. Don't think that just because you are given a motivation and intuition behind the concepts everything is just going to become easy to understand. Even motivations and intuitions need work to be understood.

* The mathematics people study in high school and first-year engineering courses is very different from the mathematics that mathematicians study. Funnily enough, most mathematicians I know don't like the approach of mathematics as a tool for other disciplines, mainly because it focuses on things that are hardly interesting (here's the 123th trick for how to solve this weird integral that we are teaching you only because you will need it to solve some engineering equation) and avoids proofs that, despite being hard, most of the time helps understanding the concepts.

* Related to the last points, an important number of math books are written not for laypersons but for mathematicians. They go straight to the point, avoid long motivations/intuitions that are not specially useful and assume familiarity with a lot of concepts. Sometimes they are written as reference books for people that already know the ideas. That, of course, makes them hardly approachable by non-mathematicians, but there are already books that do that. Just because a book or a way to teach math is not of your liking does not mean it needs to be changed.

* Not all mathematical concepts need to have a direct application. Sometimes, things are studied just because they seem interesting or beautiful. Searching for motivation needlessly in these cases tends to be a waste of time. It's like reading a novel or solving a puzzle: you don't need to know "why", just enjoy it. If you're lucky applications can appear later, but there's nothing wrong if they don't.

~~~
marcosdumay
> Motivation and intuition are important, yes, but so are definitions and
> formality.

Yet, many (maybe even most) mathematics professors and books insist on only
teaching the later two...

Every time a similar discussion comes up in HN, there's a post like yours,
pointing that the thing is too difficult to break into small problems like the
one pointed. Yes, the thing is all very complex. Yet, the pointed problem is
still a problem, and people are still not solving it.

~~~
gjulianm
Honestly, most mathematics professors I've had have attempted at giving
motivation or intuition about things. Not always useful, not always correct
and sometimes dangerously misleading, but the attempts are there.

Regarding the posts like mine, they come up because the majority is the other
view on the matter: that there must be some way to hack this that somehow is
going to be found in the HN comments, and that professors/book writers don't
care. And the reality is different: most mathematicians care about intuition
and motivation. It's their basic tool of work. But transmitting those ideas
and transmitting them effectively is not easy. In fact, there's this funny
phenomenon that I've seen in myself and it seems to apply to a lot of people:
we forget the intuition we are given for a problem if it doesn't click right
away.

I also refuse completely the premise that "people are still not solving it".
In this post there are people linking to resources on books/pages with new
ways to teach mathematics. People are solving it and each time getting better,
and however it's never going to be straightforward to teach mathematics (just
like it's never going to be straightforward to teach anything, mathematics is
only seen as special because it has a lot more presence in education that
other subjects).

------
ktRolster
He's talking about a fairly advanced math topic, abstract algebra.

At some point, you graduate from "being taught" to "teaching yourself." By the
time you get PhD, you _need_ to teach yourself, because you're studying things
no one has ever studied before.

~~~
mathgenius
But this whole mathoverflow post is professional mathematicians complaining
about how difficult it is to "teach yourself".

It's kind of sobering to realize that even the pro's have this problem.

~~~
skybrian
I'm not a mathematician, but it's my understanding from what I've read that
part of it is becoming used to groping around in the dark, sometimes getting
stuck, and accepting that as normal. Solving the really tough puzzles means
getting stuck a lot.

This might explain the relative lack of attention towards the user experience
of non-mathematicians?

~~~
jordigh
I find it amusing that you call it "user experience", a very computery/hackery
term for mathematics. There are so many computer-like expectations for
mathematics that I see on HN. :-)

Anyway, yes. Every mathematician I know acknowledges that frustration is the
natural state of affairs. If you're not frustrated that's because you haven't
been doing enough mathematics yet. There's always a bigger problem, a new
concept to master, a new way to look at an old idea.

~~~
skybrian
Yes, to extend the metaphor, writers often pride themselves in offering a good
"user experience." Bad writing does not flow smoothly and is unnecessarily
difficult to read.

Good games try to provide an optimal learning experience, providing just
enough challenge to be interesting without players getting stuck. Play-testing
is vital; if your players commonly get stuck in ways you didn't intend, it's a
bug.

There's a lot to be said for designing a learning experience to flow smoothly.
We can admire the work that goes into making that happen. (It then seems
strange that, by contrast, writers of math books often don't seem to be
playing the same game.)

One thing a well-designed experience doesn't do, though, is prepare you for
being stuck and overcoming difficulty when you're not on an artificially
smoothed path.

~~~
jordigh
> It then seems strange that, by contrast, writers of math books don't seem to
> be playing the same game.

Oh, but they _are_ playing that game. It's just a _very_ difficult game.
Everyone wants easy math books and lots of people are trying to write easy
math books (for example, my buddy Ivan and his No Bullshit guides:
[https://minireference.com/](https://minireference.com/) ). It's just a very
difficult game, and very few have come close to success. When they do succeed,
it's usually only for one kind of audience and not another. For example,
Spivak's _Calculus_ is widely admired in the mathematical community for its
presentation, but I wouldn't be surprised if HN derided it for being stuffy,
too mathematical, elitist, and full of itself.

------
hyperpallium
> And of course it is historically backwards; groups arose as people tried to
> solve problems they were independently interested in.

Reminds me of the joke that philosophy students university learn the work of
people who didn't go to university.

Would a text written by the discoverer of a field be more interesting?

I've found important papers easier to read than textbooks covering them...
OTOH the original paper can be too close to their own motivation, and not
treat - or yet be aware - of its general significance.

A motivating problem doesn't have to be practical or relatable... it just must
lack obvious solution. A puzzle.

~~~
mrout
Good example of something (although it's perhaps a bit trivial) that is a
puzzle that seems to make even non-mathematicians curious is the
'justification' for greco-latin squares.

The idea is that you have 6 files of 6 men. Each is of a different regiment,
each is of a different rank. Is it possible to arrange them so that no row and
no file have two men of the same rank or from the same regiment?

You can mention this in your first lecture on algebraic geometry (or, for that
matter, combinatorial geometry i.e. matroid theory) and then come back to it
when you talk about projective geometries.

------
jgord
Partly this is a meme diffusion problem - eg. we have really good diagrams
that explain visually why Pythagoras' theorem holds ... yet students often
don't see these more intuitive forms.

Another example is the Feynman Video Lectures are effectively inaccessible,
due to being in an ugly format - they should be on youtube as a planetary
resource.

I was recently looking at reviewing University chem so I can have informed
discussions with my teenage son.. Atkins has a great book, but at an
exorbitant price. College texts seem to be a kind of scam. Some would argue
its morally justified to pirate such content.

We seem to be stuck in all these local minima for minor psychological or
economic reasons. There should be open texts that cover most of the basics of
highschool and freshman science, with upkeep costs shared by
universities/schools or covered by a library tax.

We can think of education methods as a technology itself, and the best
technology, namely the best explanations, are much much better than the
average - how do we propagate the best ideas ?

Having ratings on quality, like those on goodreads and amazon, seems to be a
practical benefit, but maybe we need smaller granularity - eg. rate a
particular diagram on an open biochem textbook wiki.

------
moron4hire
My pet theory is that there are financial incentives to make bad text books.

Text books are usually written by university professors, often the professors
from whom you are taking the class. There are absurdly many entry-level
textbooks for a subject whose beginning parts probably haven't changed in over
100 years. They do this at the behest of the university, which will be
capturing their royalties under an IP clause in their employment contract. The
university intends to sell this book for upwards of $200 to a captured
audience of teenagers who don't yet have the life experience to know they can
opt out of putting up with bullshit. If the university doesn't have a constant
churn of new editions, then the books will very quickly filter into the
secondary market where they will be drastically discounted. So universities
pressure professors to write textbooks quickly. And university professors
aren't exactly the best-paid vocation. Invoke "good, fast, cheap: pick two"
and you see it's "good" that is getting dropped on the floor.

------
m23khan
Frankly, I think the old World habits of people distancing themselves from
distractions and to involve their self in deep thoughts relevant to their
fields, experimenting tirelessly and then collaborating with like minded
personalities are either dead or severely limited nowadays.

With such pervasive usage of TV, internet, cellphones, telephones, material
items, shopping, entertainment over the last few generations, we have gotten
to the point where we are no longer producing Einsteins, or Thomas Edisons or
Babbages. These days, your typical 'scientist' is a guy more concerned with
dressing and appearing hip and is more concerned with being a CEO/marketing
than with actual trench work in the scientific plains. These are the same
types who encourage in turn for younger generations to follow their 'hearts',
to be more 'social', to refrain from 'dry and boring studies' that consume
one's entire lifespan.

------
stared
It goes back to Gauss and "no self-respecting architect leaves the scaffolding
in place after completing the building" \- about intentionally leaving all
motivation, heuristics etc aside.

Though, compare it with
[https://terrytao.wordpress.com/](https://terrytao.wordpress.com/), full of
insight.

~~~
Chris2048
Does no self-respecting software dev leave comments/documentation behind? A
software program is the equivalent product to a blueprint, not a building. And
an architect might leave guidelines and annotations on those blueprints (they
would not dismantle scaffolds, that's a builder).

------
basicplus2
One of the biggest problems I think is that most experienced mathematicians
seem to forget that the written forms of mathematical systems contain
significantly shortened symbology which requires significant understanding of
what is NOT written explicitly​.

The most basic example I can think of is "ab" meaning "a x b" but the "times"
function has been deleted but still needs to be understood.

I find when reading mathematical books I cannot follow examples and
progressions to the next level then the next level etc as at every progression
there are significant pieces of information that are missing yet text books
rarely if ever mention what is not written, so how can the novice possibly
figure it out.

------
tnecniv
The best math class I ever took was probability, where the professor worked
history of the field and famous historical examples into his lectures. It
helped that probability has a colorful past, but the right motivation really
brings things to life.

Also, for self-teaching, I've found some math books that are setup to be in
the form "Topic A with Applications to Topic B." If I care about B, such a
book will typically does a good job motivating A, even if it isn't the purest
introduction to the area. I can always read a book that is a more canonical
intro to A later.

------
petters
Peter Lax wrote a graduate text on functional analysis where every other
chapter consists of "applications". Even though the quotation marks are
certainly warranted, I liked that concept.

~~~
ice109
name of book?

------
badpenny
I've often thought that one of the main problems with pedagogy, at least the
kind that tends towards the abstract, is that it tries to give you answers
without prompting the questions.

I suppose you could argue that it's the student's responsibility but maybe
that would require insight and inspiration on a par with that of the person
who came up with the answers in the first place and I think it's fair to say
that that's an unrealistic and unreasonable expectation.

~~~
marcosdumay
> I suppose you could argue that it's the student's responsibility

You'd then argue that it's the job of the less experienced people around to
deeply understand the world's problems. I don't think it's a good argument at
all.

------
StillBored
For lower level courses (say calc and below) the books written in the early
1900's for students seem better. Of course there are plenty of stinkers there
too, but it seems being able to explain a topic in a clear concise manner with
applications was prized more. The text books my kids have in comparison are
utter garbage in their effort to present the material in dozens of nonsensical
manners to help those that didn't understand the primary methods. Plus
"challenge" problems that rely on missing knowledge abound. The perfect
example I had of this is when my child was in 3rd grade as part of the
homework there was a set of algebraic word problems with multiple variables.
When I confronted the teacher, she didn't see anything wrong with teaching a
"trick" to solve problems where the underlying math was two or three grade
levels ahead (said trick, was so narrow an unwieldy to basically be useless
for any kind of problem more complex than ones made up for 3rd graders)...

The bottom line seems to be that the "noise" level keeps increasing to the
point where the core fundamental concepts are lost. Which is to bad, because
teaching "tricks" which don't clarify the problems, or make them simpler to
solve is IMHO just a waste of time.

BTW; For abstract algebra there are a number of "applications" books which
teach the core concepts necessarily to understand error correction or
whatever. Use those books first, and then read the more traditional text
books. The textbooks should be considered more of a reference book than
something that should be read from cover to cover. (although that itself is a
problem because jumping into the middle isn't easy).

------
daxfohl
Why do holy books contain so much detail and so little enlightenment? Perhaps
the details are what matters. Enlightenment is up to the beholder.

------
khazhoux
If a dry presentation of groups doesn't excite you, then there's plenty of
books that are full of examples and motivations.

Personally, I prefer the dry stuff (e.g., Herstein) because that's the
abstract-est abstraction. Rotations and matrices are groups? Don't care. I
just wanna see the strange hidden properties of abstract structures reveal
themselves.

~~~
gunnihinn
> Rotations and matrices are groups? Don't care. I just wanna see the strange
> hidden properties of abstract structures reveal themselves.

... for example by noting that rotations and matrices form a group?

------
pzh
I thought "God Created the Integers" by Stephen Hawking was a pretty good
high-level view of the history and progression of mathematics. It did give me
some 'aha' moments about things I knew but never realized how they were
developed.

------
Nano2rad
There are two kind of mathematics books, pure mathematics and problem
oriented. Pure mathematics text books needs not give real life examples or
context, that is the way they are supposed to be.

------
calebm
"Who is Fourier? A Mathematical Adventure" is a great (though rare)
counterexample - it is wonderfully intuitive. It's the best math book I've
ever seen.

------
hal9000xp
In the same way, I find most linear algebra books annoying.

Throwing on you dull definition of matrix multiplication is completely useless
unless you know where this definition comes from.

~~~
Chris2048
Yes! even a visual depiction of matrix multiplication, while helpful in some
ways, isn't useful unless you relate it to an application.

------
letitgo12345
Might be just laziness. Far easier to put down everything that you know in the
final form than try and figure out how to present it in a way that will be
most intuitive.

------
baby
I think it depends what book you're looking at. Pedagogy in education is a
pretty recent thing IMO.

As of the teaching side, I went through my entire math bachelor without
understanding what were the applications of what I was learning. Now that I do
cryptography I finally understand some of these. There was also this course by
Gilbert Strang on matrices that taught me that they were used in compression.
None of my teachers could have told me that...

------
kabanossen
There is an exception, "Calculus Made Easy" by Silvanus P. Thompson from 1910.
[http://www.djm.cc/library/Calculus_Made_Easy_Thompson.pdf](http://www.djm.cc/library/Calculus_Made_Easy_Thompson.pdf)
[https://en.wikipedia.org/wiki/Calculus_Made_Easy](https://en.wikipedia.org/wiki/Calculus_Made_Easy)

------
j45
I had a math teacher that explained that beyond simple and clear explanations,
the other way to learn math was to do example questions. Lots of examples, to
see all the patterns and subleties. The subject he'd most often quote was
permutations and combinations - either you got it pretty much instantly or it
would just be a struggle that you could only improve at so much by doing a lot
of practice questions.

------
erikb
I think it's also strategical. Math is an area of science that most of the
time is not worth as much as it costs to continue. But sometimes, one of these
little things turn out so huge that they change all our lives. So we really
need math, but most of the time there is no logical reason to invest in it
(knowledge, time, money). What to do about it?

One way that seems to have begun common in Math is to make it magical. The
entry burden is hard as hell, and most reasonable things in math are expressed
in a way that as best sounds mystical to common people.

This gives math some kind of credibility. Nobody wants to be the one to say
how little they actually understand about it, so they continue to support the
crazy magicians instead of losing face. And in the end humanity is better off
for it.

PS: You can see that it is not necessary to be so cryptic but still math
continues to do so, when you compare it to programming. For instance math
continues to use a greek letter ∑ (sigma) to express it. In programming it's
mostly a "for loop" or a "sum() function". Most people can understand
"sum([1,2,3])" or "for <something> do <something> done", but they don't know
the greek alphabet. So it's possible to encode math more readable, but math
continues not to do so, and as argued before, probably also has good reason to
do so.

~~~
mathperson
sigma is one character versus at least 3 for "sum() function". it literally
takes 20 seconds to figure out what the symbol is...

~~~
abecedarius
But the _plus sign_ is also one character. Why not use a big plus sign
instead? That would not only be clearer, it generalizes systematically: use a
big multiply sign instead of a capital pi, etc.

When I was a kid I was a little intimidated by those higher math books with
the "Greek E's" in them. Years passed before I learned in my early teens what
they actually meant (and that it was simple, and they weren't even E's).

~~~
mathperson
THE BIG PLUS SIGN IS USED IN MATHEMATICS! It has an entirely DISJOINT meaning
from simple summation...

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

~~~
abecedarius
That's a plus inside a circle. This logical tweak to the notation was proposed
by someone I forget, maybe 3blue1brown.

~~~
mathperson
no its the direct sum notation. you have no right to tell mathematicians what
notation they should or should not use. what you are entitled to is to write a
mathematical paper and use some notation and try to market it. but that
requires getting a phd, learning mathematics, publishing on the arxiv, going
to conferences, going to talks, talking to mathematicians,......... its much
easier to say "BUT MUH PLUS OH SCARY GREEK!"

~~~
abecedarius
My point was that the direct-sum sign you brought up was different from the
plus sign that I brought up. There's no conflict.

~~~
mathperson
I am sorry if I seem frustrated. its just I can tell you are a thoughtful,
curious person, who seems like you want to enjoy mathematics. but instead i
feel like you are lapsing into a math phobia and a concern with trivialities.
the fact you seem genuinely interested makes it more frustrating. mathematics
is not notation. notation is just arbitrary historical nonsense. an OLD
professor I know complains about using fraktur (annoying german script used in
abstract algebra for ideals-german mathematicians in the 1880s developed the
heart of modern algebra) because "we won the war". don't let it blind you to
the beauty and depth and complexity of mathematics. yes sometimes its annoying
AF. (god don't even get me started on what physicists call things). but the
struggle is worth it and there are things that can be improved but there is no
magic bullet

~~~
abecedarius
Thanks for going to some trouble explaining your point of view.

I'll try to clarify mine: yes, a plus sign vs. a capital sigma can be quickly
explained. Let's imagine you're reading a short paper about, say, signal
processing, and it says in a footnote or prefatory matter "we use tau for 2
pi". Also it uses the sum notation I brought up. Oh, and the exponential is
different too: maybe one of these
[https://math.stackexchange.com/questions/30046/alternative-n...](https://math.stackexchange.com/questions/30046/alternative-
notation-for-exponents-logs-and-roots/1158802) or maybe just the electrical-
engineering angle symbol for exp(i theta).

Now you start reading the actual new material but even the fourier series
looks all different and you're like "why is the author imposing this cognitive
tax on me?" You can work through it, but why? The author must be a weirdo.

That'd be a reasonable reaction. But if notational trivia matter to those of
us "with a freakish knack for manipulating abstract symbols"
([http://worrydream.com/KillMath/](http://worrydream.com/KillMath/)) then they
must also matter as a barrier to people who are more average in that regard. I
agree if you're saying that something like sigma vs. plus sign is far down on
the list of ways to improve mathematical communication -- even any notational
reforms would not come first. (Though see
[http://cognitivemedium.com/](http://cognitivemedium.com/) for some more
thoughts on how computers doing what paper can't opens up new possibilities.)
I also agree that learning must be active -- learning isn't just a matter of
more efficiently pouring knowledge into a student's head. The difficulty can
be roughly divided into accidental and essential; you must do well at engaging
with the essential difficulty of the subject to engage well at all. But
smoothing the accidental, trivial difficulties is not, in aggregate, trivial.

------
godmodus
Because they assume a false premise (hah! Does this count as a pun?) and take
a high road. Best series of books i read about matg tgst really helped me were
the "for the practical man" series of books!

Another book i recommend that helped me was "the architecture of math" by
pierre basieux.

These books really assume nothing beyond the ability to read and do a great
job!

~~~
Rzor
I can't find any Architecture of Math authored by that person. Are you sure
that's the author?

~~~
godmodus
[https://www.amazon.de/Die-Architektur-Mathematik-Denken-
Stru...](https://www.amazon.de/Die-Architektur-Mathematik-Denken-
Strukturen/dp/3499611198)

it might not have an english translation, but there you go man

here's a good reads link with all his books
[http://www.goodreads.com/author/show/745580.Pierre_Basieux](http://www.goodreads.com/author/show/745580.Pierre_Basieux)

the original is in french, it seems the only options to read it is to either
know german, or french!

------
matt_j
I enjoy math books like:

\- e; The story of a number (Eli Moar) \- An imaginary tale; The story of -1
(Paul Nahin) \- The Poincare Conjecture (Daniel O'Shea) \- The man who loved
only numbers (Paul Hoffman) \- Prime Obsession (John Derbyshire)

They're part biography, part history, and give a little colour to the subject
that isn't available from your typical college textbook.

------
FabHK
A wonderful book that doesn't suffer the discussed flaw is _Visual Group
Theory_ by Nathan Carter, discussed on HN earlier. It provides ample
motivation and examples before diving into the theorems.

[https://news.ycombinator.com/item?id=11745486](https://news.ycombinator.com/item?id=11745486)

------
random_comment
When I taught maths at university, I would always try to include in every
lecture a couple of slides showing how the lecture could be used to get a job,
or to solve a real world problem in computer programming. It's weird that
other disciplines seem to ground knowledge much better than maths, when it
isn't hard to ground maths.

------
neom
I really really wish I could do math. I have very high dyslexia and
dyscalculia and I really really struggle to understand numbers, it's just so
difficult for me to think about them, think about putting them together, even
basic addition can be a complete struggle. I'm not sure why, but I can
somewhat understand geometry.

------
thomastjeffery
The same can be said about programming.

Reference and theory are very useful, but context is how they are tied
together in implementation.

~~~
Mathnerd314
By the Curry–Howard correspondence, programming is in fact (formal) theorem
proving.

Mathematics got a lot less interesting after I realized it amounted to a
giant, informally-specified, mostly undocumented body of code designed to run
on the human brain... from that perspective it's hard to see why one should
prefer mathematics to a well-written software program that does the same
thing.

~~~
bjl
That's not quite true. Curry-Howard only applies to constructivist
mathematics, which is a very tiny subset of mathematics proper.

~~~
gergoerdi
That is a much more complicated question than you make it sound:
[https://cstheory.stackexchange.com/q/5245/1802](https://cstheory.stackexchange.com/q/5245/1802)

------
onmobiletemp
Its because math is used as test material. Thats all it is in american
educations and many others i might add. Its a fucking crime. All of science
and almost everying else is treated similarly. They build tests into the
material you are to learn. At the end of the day you get a monstrosity. I say
that if we are going to try to hide iq tests inside the material then we
should have no qualms about simply giving everyone iq tests separately from
learning material. Yes there are flaws with that proposal but it would still
be better than what we have now where all of the material is molested. Imagine
if people actually got a thorough education. No more grtting to the job only
to learn that they didnt teach you what you need to know. In computer science
this problem is fucking atrocious.

------
oldmancoyote
The more closely you study something, the more defuse it becomes until when
you totally understand it, it has completely disappeared from view.

If you can no longer "see" a thing, you can not usefully explain it.

~~~
Qwertious
Relevant:
[http://lesswrong.com/lw/kg/expecting_short_inferential_dista...](http://lesswrong.com/lw/kg/expecting_short_inferential_distances/)

------
kwhitefoot
See A Mathematician's Lament:
[https://news.ycombinator.com/item?id=14331752](https://news.ycombinator.com/item?id=14331752)

------
EGreg
When I was teaching calculus, I made a fundamental decision of how to define
limits:

 _I used limits of sequences._

In our university, we encounter limits in either a handwavy way in Calc I or
an epsilon-delta way in Advanced Calculus. Sequences and series are introduced
in Calculus II.

Continuity is then described in the same terms. Or perhaps in terms of open
sets if there is some topological topic.

I think this is pretty terrible for intuition. Not just that, but it's not
even general enough - it requires normed spaces, so then you have to
generalize again.

Much simpler to talk about ancient Greeks and Zeno's paradox. And then
rigorously define limits of sequences, and define limits of real valued
functions in terms of "for any sequence x_n that approaches x, y_n = f(x_n)
approaches y". Simple and right away lets me show counterexamples beyond "left
and right limits", like cos(1/x), and show students how to produce two
sequences that converge to different numbers.

There are similar ah-ha moments when discussing fundamental concepts of linear
algebra, number theory, complex numbers etc.

The two best books I have ever found on teaching Complex Numbers are:

1) Bak and Newman

2) Schaum's Outlines

They actually give you the understanding and ceeling behind WHY analytic
functions are the way they are, and derive holomorphic functions from that.
Imho a more terrible approach is that of Serge Lang and proving everything the
other way, with Taylor power series.

Bottom line - make a directed graph of how you will teach your subject and
then figure out the best entry point an direction for the greatest cohesion,
as you would when telling a story.

If you are curious, now I teach a course on "Thinking Matematically" and here
are this semester's results of that approach:

Numbers and Algebra:
[https://qbix.com/docs/mathematically1.pdf](https://qbix.com/docs/mathematically1.pdf)
([https://vimeo.com/215335666](https://vimeo.com/215335666))

Sets and Infinity:
[https://qbix.com/docs/mathematically2.pdf](https://qbix.com/docs/mathematically2.pdf)
([https://vimeo.com/210500111](https://vimeo.com/210500111))

Boolean Algebra:
[https://qbix.com/docs/mathematically3.pdf](https://qbix.com/docs/mathematically3.pdf)

Logic and Probability (Coming up)

The above videos were made with help from video exditors on upwork.com

------
gcr
What are some recommendations for math books that really are deeply
enlightening?

------
lois
This is something I think about often. Maths is one of those subjects which is
taught repetitively rather than philosophically, and yet there couldn't be a
worse subject to teach in such a manner. It forms a barrier-to-entry which
mathematicians probably care for, glancing at some of the quotes already
posted here, but doesn't help people who would make excellent mathematicians
if only they had the encouragement.

I always found mathematics self-explanatory. From all the repetitions the
understanding came naturally, and I think there is definitely a subset of the
population that has what you might call 'aptitude' for maths. It makes sense,
because philosophically it is self-explanatory by definition. LHS = RHS - the
trick is to prove it or fill in the blanks.

But I dare say the majority of people aren't 'apt' for maths in the way in
which it is taught, but at the same time it's totally unfair to rule them out
as maths-stupid. Many people who have no mathematical knowledge whatsoever
still prove rather deft at deducing when their partners are lying or when an
argument in a debate is self-contradictory. People who failed their
mathematical education go on thinking they suck at math, but when they play
video games and figure out optimal strategies and formulae for success in the
game, it's not all that different. Sometimes the mathematical understanding
comes later to people as a direct result of being forced to reason about
mathematical problems in an applied setting and discover that they could have
been good at maths all along if they had only understood the 'why' of the
exercises and formulae they were doing.

I think there are two big stumbling blocks that stop people from taking a
bigger interest and investing more concentration and care into maths: firstly
people mix up arithmetic with maths, and assume from the fact that they take a
long time to divide a couple of numbers (or get the wrong answer when they do
so) that they are doomed to be crap at maths.

But that's utter BS. I'm hopeless at mental arithmetic, but maths isn't about
adding numeric values, its about deduction and reasoning, and I'm certainly
not alone in being a terrible arithmetician and a good mathematician.

The other issue that people struggle with is that the notation itself isn't
clearly explained or appears daunting, especially if they didn't go beyond
compulsory education. It can prove quite distracting because a person might
have questions as to why limit notation looks the way it does or what the hell
the integral sign means, when really it's no different to choosing commas and
brackets to denote semantic delineation in written language.

Take limit notation or summation. The placement of the various numbers is
arbitrary on a fundamental level, it's just the standard everybody agreed to
use. If someone good enough at math sat down and tried to build up math from
first principles, with no knowledge of modern mathematical standards and
notation, he/she could come up with the same formulae and concepts but an
entirely different way of representing them.

That's exactly what happened really. you had Leibniz and Newton just
organizing information in a way that made sense to them, and it stuck. An
explanation of how arbitrary the notation is on a fundamental level would
probably make a board full of symbols and algebraic letters considerably less
daunting for those who could-but-daren't understand it.

I think there's a big problem in education as well. I'm from Great Britain and
growing up I think the biggest mistake in our education system is the dire
failure to explain mathematics in a way that is friendly for people who aren't
tip-top at abstract thinking or imagining.

Take the humble function, for example. teacher says "a function takes an input
and produces an output. so f of x equals y minus 5x..." \- and half the class
stares blankly, daydreams for 15 minutes, chatters through the "work your way
through the textbook" phase and does one of two things before the teacher goes
through the solutions:

    
    
        A. copy answers from the back of the textbook
        B. copies an adjacent boffin.
    

I think the much maligned set theory actually provides a very good way to
teach about functions, and yet it doesn't appear until you hit college, and
then suddenly a function is referred to as a mapping, without any preparation
or explanation of whether there's a difference between 'function' and
'mapping'.

I was endlessly helping classmates in school and I often think about how the
education system could have been better and made math more accessible. The
conspiracy theorist might say that society cannot afford for everybody to
grasp mathematics and get a /good/ job, but hopefully that's not possible.

Geometry in education is a big fail as well. when I was growing up,
trigonometry wasn't explained at all, it was just repetition of applying trig
tables. Nothing visually relating right-angled triangles and circles like
Thales was even touched upon until college.

Secondary education in UK tries to cover to many things. Not that there's any
way of chopping math down to a single textbook or subject area, but there's
often little in the way of structure and it's about cramming as many formulae
down the student's throats and then examining them on their ability to apply
what they have repeated. but you can't apply what you repeat, you apply what
you learn and grok.

I'm not sure why there is this enormous failure in education. It could be
because the people who write the books and lesson plans already grok
mathematics and forget to give people aids to intuition or intrinsically
understanding what they're doing. Or maybe it's because a mathematical
education excludes the philosophy of math and set theory which is a mistake.
Set theory is perfect to start off with, it gives insight into functions,
probability, everything really. Can always discredit the /project/ of founding
mathematics on set theory later.

Of course, maybe I went to a bad school, and it was a few years ago now so
perhaps things have changed - but I don't think so. most of my younger
sister's friends have a worse understanding than the disinterested kids when I
was growing up, but that could be down to the whole fast-food, instasnaptwit
culture and a hundred other things that seem to be distracting people from
anything academic.

------
ianamartin
This is a general problem with textbooks. Textbooks are not written for
students. They are written _by_ experts in the field, and the audience is
_other experts_ in the field.

This isn't necessarily a problem. It's a good thing to have experts working
together to codify the current state of affairs, but it isn't necessarily the
best teaching device.

Even when you have people writing books that are intentionally targeted at
people new to a topic, it's easy to forget how much you know and how much
beginners don't know. I'm working on a Music Theory book with an audience of
total beginners, and it's extremely difficult for me to put myself in that
mindset. In doing research for that book, I've been going over many of my
college music theory textbooks, and re-reading some of the treatises about the
subject going back to Pythagorus and Plato.

Things that were infuriatingly opaque to me as an undergrad are now--after
decades of study--just plainly obvious and practically self-evident. You
forget how little you knew after a while.

If there were one thing I could go back in time and tell myself when I was
younger, it would be to make it clear that textbooks are not there to explain
it to me like I'm five. Textbooks are scholarly works intended to be as
precise as possible about the current consensus of experts in the topic area.
Approach a textbook the same way that you would approach a philosophical
treatise. You aren't going to get it all the first time around. And I do tell
that to my violin students who are now starting to go to college.

Textbooks are designed to be paired with an instructor who can interpret the
book and guide the students. They are not actually designed to be self-
sufficient courses of study that you can simply read and learn from.

The reason for this is that this is the model of education that's been pretty
much generally accepted. The university model really hasn't changed a whole
lot since medieval times and arguably going back to greco-roman times. At
least in the West. I don't know enough about Asian culture or history to
comment about that. You have a master and students and some texts laying out
the way of things. And in order to become the master you have to jump through
a certain set of hoops.

It's an almost religious sort of process, in some ways. There's a tradition of
a certain type of study with anointed masters, there are holy texts that you
don't understand but must adhere to. And if you put in enough time and survive
certain types of hazing rituals, you get the privilege of becoming anointed
yourself, making very little money, and possibly contributing to a holy text
yourself.

Out of the many things that get cited as disruptive with respect to the
technology revolution, one thing that doesn't get talked about a lot is the
way that the internet has disrupted the education market.

An "explain it like I'm 5" post on reddit is far more practically useful than
any textbook on any topic, _if_ your goal is to help a person learn about a
topic. I spent the vast majority of my life studying violin, and music theory.
And I was a professional performer for 20 years. When I got burned out on
performing and traveling and never making enough money, I got online and
started learning, practically, how to code. At first just enough to get a
junior job. And I kept reading, and I got better. It's been 11 years now, and
I haven't looked back. I can write code _and_ play the violin when I feel like
it, and work on a book about music theory. All that as a college dropout. It's
a life I'm deeply grateful for.

A generation ago, changing careers would've meant going back to school,
probably taking on some debt, finishing up a degree that I never really wanted
anyway, and then going to start something else. Which is a pretty big pause in
your life when you're in your late 20s.

I didn't have to do any of that.

At the same time, rigorous textbooks certainly have a place in the world. The
same way that Plato's _Timmeus_ or Descartes _Compendium musicae_ have a
place. The biggest problem with textbooks is that people misunderstand their
intended purpose and audience.

They are tools created by academics to help create more academics. Nothing
more; nothing less. If you want to participate in the academic system, you
have to play by its rules. That means that you deal with these textbooks and
the professors who guide you through them until you yourself are a professor,
and you can in turn, guide others.

For those of us who don't want to do that particular type of work and would
rather be educated practitioners, there's the internet.

I'm glad we have both options available now.

~~~
mathperson
this is dead wrong. "Textbooks are not written for students" yes yes they are.
unless you reading an review written last year summarizing the last ten years
for a very very very specific sub-field....YES THEY ARE WRITTEN FOR STUDENTS.

------
Ericson2314
Formal math in theorem proper with copious marginalia +1

------
the6threplicant
This is why lectures are so important compared to a text book.

In a lecture you try and emphasis how some things are important - while other
things you can hand wave away. A textbook can't do that.

------
doener
In may cases better than reading the book:
[https://www.blinkist.com/](https://www.blinkist.com/)

It's only the gist of it.

------
elchief
There are no hard concepts, only bad explanations

------
graycat
I agree with the sentiment of the OP.

For an answer, there have been various influences:

(1) Whatever math was before 1900 or so, by the time of the Russell paradox
and its fix with axiomatic set theory, the _style_ of the fix was to be close
to Russell-Whitehead (if I have that right) idea that proofs could be checked
essentially mechanically by just symbol substitution and manipulation. E.g.,
in those days there was a book on the natural numbers, that is, 1, 2, 3, ...
that apologized for numbering the pages before the natural numbers had been
carefully defined!

There was even a name given to this style of writing, _telegraph_ style.

(2) Of course, the books written on axiomatic set theory easily fell into the
telegraph style. Even there the writers were getting into trouble: They gave
names for the various axioms; they didn't explain why the names they gave were
appropriate, and I never could discover why. But I was eager to get out of the
sub-sub-basement of axiomatic set theory ASAP so just did a f'get about it.

(3) When books were written on abstract algebra, e.g., basic set theory,
construction of the main number systems -- the naturals, integers, rationals,
reals, complex -- and then went on to the main algebraic systems defined with
axioms -- groups, rings, fields, vector spaces -- it was easy to stay with the
telegraph style. E.g., it was tough to find a book on abstract algebra that
also discussed group representations and its applications to quantum mechanics
and molecular spectroscopy.

(4) Long calculus was often done with a lot of intuition and nothing like some
carefully done definitions, theorems, and proofs as in, say, W. Rudin,
_Principles of Mathematical Analysis_. And physics and engineering kept
drawing diagrams with "little interval dx" etc. So, when abstract algebra was
proving theorems, the calculus authors also wanted to be careful at least
about delta-epsilon arguments. Then including a lot of physics, mechanical
engineering, touching on the heat equation or fluid flow, was considered off-
topic. Bummer.

(5) The series of astoundingly carefully written books, close to telegraph
style, by the team Bourbaki was influential.

(6) During the Cold War and the Space Race, US math was awash in grant money
and essentially turned its back on the physical science motivations and
applications. Some of the funding people started to get angry about that, and
we got the Tom Lehrer song and joke about abstract math being about "the
analytic algebraic topology of locally Euclidean metrization of infinitely
differentiable Riemannian manifolds" or some such.

But, sure, especially in analysis, for a good proof, there's often a good
picture and if can see the picture then can construct the proof easily. E.g.,
for positive integer n, the set of real numbers R, and convex f: R^n --> R,
that f is continuous has a really cute picture. Same for Jensen's inequality.
In linear algebra, the polar decomposition says that each square matrix is
just (A) a rigid motion, rotation and/or reflections followed by (B) moving a
sphere into an ellipsoid by stretching and/or shrinking on mutually orthogonal
axes. One or more of the axes goes to zero if and only if the matrix is
singular. Etc. Nice picture.

Currently, then, there is an opportunity for math authors to include
motivations for their subject, definitions, and theorems, intuitive
descriptions and helpful pictures, applications, issues, open questions, etc.
Uh, when reading a proof, for each of the assumptions, check off where it was
used in the proof! The definitions, theorems, and proofs can still be fully
precise and solid.

Some students of, say, analysis have long tried to find and draw pictures that
would clarify what was _going on_ in some definitions, theorems, and proofs. I
would advise new students to do that also.

------
Melchizedek
Perhaps it is also the case that many mathematicians are far to the autism
side of the spectrum, and find it difficult to verbalize "soft" aspects such
as motivation and intuition, even though those are extremely important in a
textbook.

It's almost as if they partly lack theory of mind, and cannot imagine that
somebody else does not know what they know, and consequently give explanations
that are only suitable for someone who _already_ knows the material.

~~~
Broken_Hippo
I'm an artist. I've been doing art since I was a child: I started oil painting
when I was 8 or something, and remember drawing and coloring being one of my
favorite activities as a young child (before kindergarten). I can't properly
explain how I see things the way I do. I can't really explain why I choose
some colors in non-realistic pieces other than "they look good", although I
know that learning color theory from the color wheel helps explain that and
helps folks learn. It took me some time to learn to explain this stuff to
others. I'm not autistic, though I likely have a mild case of dyslexia.

I always imagine that skilled mathematicians are somewhat the same. It isn't
that it only works for someone that already knows, it is more that they are
writing the books for folks whose mind simply has that sort of slant to it.

If we change all the books to help someone like me - I generally did poorly in
algebra, trig, and calculus but found geometry fairly straighforward - that's
going to let the other folks down because their mind's logic simply doesn't
work on the same wavelength. This isn't autism, but simply human variation.

~~~
watwut
I think that there is difference - there is nothing natural about things like
notations, axiomatic system or concrete theories. They have been developed for
hundreds of years and have to be learned. Kid will not invent them intuitively
(unlike colors matching). As you are learning math, you oftentimes you don't
understand for long and then something clicks and suddenly you get it.
Mathematicien coming to new theory oftentimes needs a lot of time to go
through just one page of article.

I am not denying that talent exist, but it just makes learning harder or
easier and defines plateau. Through, if you was good in geometry, then your
brain works well enough in math (meaning some click on algebra did not
happened but you are unlikely to be unable to think that way - thinking is not
that dissimilar).

