Incoming links: Jakob Schwichtenberg
Ciro Santilli has a bad memory for events that happened a medium time ago, for example in order of months/years. Especially if they are one-off things that have no relation to anything else.
For example, Ciro never remembers which places he travelled to just once, and who was in each trip! He has images of several places he travelled to in his head, and would recognize them, but he just doesn't know where they were!
Another example, Ciro was looking at the carpet at their house, and asked where it came from. His wife replied immeidately: from Bercy shopping quarter in Paris about 10 years ago, and you took it on your back for a long walk until we could find the bus back home because we were concerned it wouldn't fit in the train!
The same goes for scenes from movies and passages from music, which explains why Ciro's art consumption focuses on innovative discrete "what happened" and "general gist" ideas, rather than, analog details such as colors and shapes.
Going back even further in time, Ciro starts to forget the less close friends he had, because the events start to fade away.
Paradoxically however, Ciro believes that this bad memory is one of his greatest strengths and key defining characteristics, because it leads Ciro to want to write down every interesting thing he learns, which motivated OurBigBook.com and his Stack Overflow contributions and his related Ciro Santilli's documentation superpowers.
It also somewhat leads Ciro to like physics and mathematics, because in these fields you "can deduce everything" from very few base principles, so if you forget them, it does not matter that much as you can re-deduce stuff over and over. Which is somewhat where the high flying bird attitude comes from. It is hard to go deep when you have to re-prove everything every time. But the upside is that anything that sticks, does so because it has a broad net to stick to, and therefore allows Ciro to make unusual and unexpected connections that others might not.
Ciro believes that there are two types of people, and most notably software engineers, which are basically data wranglers: those with bad memory and those with good memory.
Those with bad memory, tend to focus on automating and improving their processes a lot. They take much longer to do one-off specific deep knowledge tasks however.
The downside of the good memory ones is that sooner or later they will find tasks that no matter how much memory they have, they cannot solve without automation, and they will fail at those.
Also, good memory people don't enable others to join the project efficiently as much.
This dichotomy also explains why Ciro sucks at code reviews, but is rather the person who runs the interesting patches by himself and finds some critical problems that the more theoretical code reviewers missed.
If Ciro had become a scientist, he would without doubt be an experimentalist, just like in this reality he is a GDB/runtime person rather than a "static source analysis" person. Those who have bad memory prefer to just run experiments over and over and observe system state at runtime.
Other effects of having a bad memory include:
- code duplication, or a constant fear of it at least, because Ciro forgets that some functionality exists already
- meeting aversion, because everything that is not recorded will fade away
- passion for backward design, because by the time a piece of knowledge learnt in school might be useful (and 99.99% won't), it will have been long forgotten
Related: jakobschwichtenberg.com/about/ from Jakob Schwichtenberg:
I'm a physicist and I try to write down things during my own learning process.In some sense, one of the biggest benefits I have over other people in physics is that I'm certainly not the smartest guy! I usually can't grasp complex issues very easily. So I have to break down complex ideas into smaller chunks to understand it myself. This means, whenever I describe something to others, everyone understands, because it's broken down into such simple terms.
On C2 wiki, therefore it cannot be wrong wiki.c2.com/?QuasiGreatTeacher:
Some people have learning disabilities, [... bullshit ...]. A lot of classic spiritual texts have been produced this way. Basically, the stupidest but most dogged disciple, if he has a neurotic habit of writing things down, will make the best teacher for the third and subsequent generations.
The approach many courses take to physics, specially "modern Physics" is really bad, this is how it should be taught:
- start by describing experiments that the previous best theory did not explain, see also: Section "Physics education needs more focus on understanding experiments and their history"
- then, give the final formula for the next best theory
- then, give all the important final implications of that formula, and how it amazingly describes the experiments. In particular this means: doing physics means calculating a number
- then, give some mathematical intuition on the formulas, and how the main equation could have been derived
- finally, then and only then, start deriving the outcomes of the main formula in detail
This is likely because at some point, experiments get more and more complicated, and so people are tempted to say "this is the truth" instead of "this is why we think this is the truth", which is much harder.
But we can't be lazy, there is no replacement to the why.
Related:
- settheory.net/learnphysics and www.youtube.com/watch?v=5MKjPYuD60I&list=PLJcTRymdlUQPwx8qU4ln83huPx-6Y3XxH from settheory.net
- math.ucr.edu/home/baez/books.html by John Baez. Mentions:
This webpage doesn't have lots of links to websites. Websites just don't have the sort of in-depth material you need to learn technical subjects like advanced math and physics — at least, not yet. To learn this stuff, you need to read lots of booksCiro Santilli is trying to change that: OurBigBook.com.
- web.archive.org/web/20210324182549/http://jakobschwichtenberg.com/one-thing/ by Jakob Schwichtenberg
Like everything else in Lie groups, first start with the matrix as discussed at Section "Lie algebra of a matrix Lie group".
Intuitively, a Lie algebra is a simpler object than a Lie group. Without any extra structure, groups can be very complicated non-linear objects. But a Lie algebra is just an algebra over a field, and one with a restricted bilinear map called the Lie bracket, that has to also be alternating and satisfy the Jacobi identity.
Another important way to think about Lie algebras, is as infinitesimal generators.
Because of the Lie group-Lie algebra correspondence, we know that there is almost a bijection between each Lie group and the corresponding Lie algebra. So it makes sense to try and study the algebra instead of the group itself whenever possible, to try and get insight and proofs in that simpler framework. This is the key reason why people study Lie algebras. One is philosophically reminded of how normal subgroups are a simpler representation of group homomorphisms.
To make things even simpler, because all vector spaces of the same dimension on a given field are isomorphic, the only things we need to specify a Lie group through a Lie algebra are:Note that the Lie bracket can look different under different basis of the Lie algebra however. This is shown for example at Physics from Symmetry by Jakob Schwichtenberg (2015) page 71 for the Lorentz group.
- the dimension
- the Lie bracket
As mentioned at Lie Groups, Physics, and Geometry by Robert Gilmore (2008) Chapter 4 "Lie Algebras", taking the Lie algebra around the identity is mostly a convention, we could treat any other point, and things are more or less equivalent.
- HyperCard: we are kind of a "multiuser" version of HyperCard, trying to tie up cards made by different users. It is worth noting that HyperCard was one of the inspirations for WikiWikiWeb, which then inspired Wikipedia
- Semantic Web
- NLab
- physicstravelguide.com/ Nice manifesto: physicstravelguide.com/about by Jakob Schwichtenberg.
- OpenStax
- www.ft.com/content/5515ec3e-0040-4d90-85a9-df19d6e3ebd2 (archive) Twilio’s Jeff Lawson: an evangelist for software developersYou can never be first. But you can have the correct business model. That company's website must have gone into IP Purgatory, and could never be released as an open source website.As a student at the University of Michigan, he started a company that made lecture notes available free online, drawing a large audience of Midwestern college students and, soon enough, advertisers. At the height of the dotcom bubble, he dropped out of college, raised $10m from the venture firm Venrock and moved the company to Silicon Valley.His start-up drew interest from an acquirer that was planning to go public early in 2000. They closed the acquisition but missed their IPO window as the market plunged, and by August the company had filed for bankruptcy. Stock that Lawson and investors in his start-up received from the sale became worthless.The website was called stubhub.com/, as of 2021 the domain had been sold to an unrelated website.He might actually be interested in donating to OurBigBook.com if it move forward now that he's a billionaire.
- Knol: basically the exact same thing by Google but 14 years earlier and declared a failure. Quite ominous:
Any contributor could create and own new Knol articles, and there could be multiple articles on the same topic with each written by a different author.
- leanpub: similar goals, markdown-based, but the usual "you own your book copyright and you are trying to sell your book" approach
- nature Scitable
OK, just going random now:
DokuWiki about physics, mostly/fully written by Jakob Schwichtenberg and therefore focusing on particle physics, although registration might be open to all.
TODO what's the point of it.
Bibliography:
- www.youtube.com/watch?v=j1PAxNKB_Zc Manifolds #6 - Tangent Space (Detail) by WHYB maths (2020). This is worth looking into.
- www.youtube.com/watch?v=oxB4aH8h5j4 actually gives a more concrete example. Basically, the vectors are defined by saying "we are doing the Directional derivative of any function along this direction".One thing to remember is that of course, the most convenient way to define a function and to specify a direction, is by using one of the coordinate charts.We can then just switch between charts by change of basis.
- jakobschwichtenberg.com/lie-algebra-able-describe-group/ by Jakob Schwichtenberg
- math.stackexchange.com/questions/1388144/what-exactly-is-a-tangent-vector/2714944 What exactly is a tangent vector? on Stack Exchange
Ciro Santilli is a big believer that there is value in tutorials written by beginners, because beginners are more likely to explain things in a way that other beginners can understand.
Even though they make more mistakes, this more approachable point of view can be very valuable.
And mistakes/omissions can be corrected on comments by people with more knowledge, so that the writer also ends up learning something new.
By other people:
- jakobschwichtenberg.com/about/ from Jakob Schwichtenberg mentions quotes C. S. Lewis book "Reflections on the Psalms"[ref]:
It often happens that two schoolboys can solve difficulties in their work for one another better than the master can. [...] The fellow-pupil can help more than the master because he knows less. The difficulty we want him to explain is one he has recently met. The expert met it so long ago he has forgotten. He sees the whole subject, by now, in a different light that he cannot conceive what is really troubling the pupil; he sees a dozen other difficulties which ought to be troubling him but aren't.