Ar­bital is a plat­form for find­ing, read­ing, and cre­at­ing crowd­sourced, in­tu­itive ex­pla­na­tions for ev­ery­thing math. Sev­eral ex­ist­ing web­sites (Wikipe­dia, MathOverflow, and Wolfram MathWorld among oth­ers) already work well as refer­ences, but it’s hard to learn from them un­less you are already fa­mil­iar with the sub­ject. Other web­sites, like Khan Academy and Bet­ter Ex­plained, have some great ex­pla­na­tions (at least for K-12 ma­te­rial) but they are limited by the fact that they are closed plat­forms. Ar­bital is fun­da­men­tally a col­lab­o­ra­tive plat­form, which al­lows ev­ery­one to con­tribute ex­pla­na­tions, add ex­am­ples, and share their ex­per­tise.

Ideal ex­pla­na­tion platform

What would the ideal plat­form for (math) ex­pla­na­tions look like? For ex­am­ple, if you wanted to learn Bayes’ the­o­rem, what would you want to see be­hind this link?

The ideal plat­form would use each reader’s ex­ist­ing knowl­edge, ex­per­tise, and learn­ing prefer­ences to gen­er­ate a tai­lored ex­pla­na­tion. If they were com­fortable with math­e­mat­i­cal no­ta­tion, the ideal plat­form would show them equa­tions in­stead of wordy ex­pla­na­tions. If they were miss­ing cer­tain pre­req­ui­sites, the ideal plat­form would make it easy to catch up on those. If they already knew half the ex­pla­na­tion, the ideal plat­form would skip past it. If one ex­pla­na­tion didn’t work for them, the ideal plat­form would offer an­other.

The ideal plat­form would be in­ter­ac­tive, as if you were study­ing with a per­sonal tu­tor. Ask­ing for a re­minder about what a par­tially or­dered set is would be as easy as hov­er­ing your mouse over a link. It would be easy to ask ques­tions and in­stantly get de­tailed an­swers. It would be easy to speed up an ex­pla­na­tion or slow it down.

The ideal plat­form would have in­tu­itive, mem­o­rable, mind-blow­ing ex­pla­na­tions that re­li­ably pro­duce that mag­i­cal “click” feel­ing. The one you get when some­thing fi­nally makes perfect sense. note A few ex­am­ples:
What if? - Rel­a­tivis­tic base­ball
Wait Buy Why—Fermi para­dox
Bet­ter Ex­plained—In­tu­itive tri­gonom­e­try
Scott Aar­son—Who can name the big­ger num­ber?
And videos too:
Vi Hart—Spirals and Fibonacci num­bers
US auto in­dus­try—How differ­en­tial steer­ing works
It would be easy to give feed­back to au­thors to help them in­cre­men­tally im­prove each page to make that hap­pen.

That ideal plat­form doesn’t ex­ist yet, but we’re build­ing it, and it’s called Ar­bital. What you see be­fore you is a beta ver­sion, and we’re go­ing to con­tinue work­ing hard to im­prove it and make our vi­sion a re­al­ity.

En­thu­si­as­tic com­mu­nity and effec­tive tools

Our top pri­or­ity is to grow our com­mu­nity of like-minded peo­ple who love helping oth­ers learn. We are avid learn­ers our­selves, and some of the most in­ter­est­ing things we’ve learned are the ones we’ve taught our­selves out­side the con­text of class­rooms and courses. We like ex­plain­ing things and shar­ing our knowl­edge with oth­ers. If you look at the suc­cess of Wikipe­dia and MathOverflow, it’s clear that com­mu­ni­ties with a shared mis­sion can pro­duce amaz­ing, use­ful, and last­ing re­sources that benefit the whole world.

We aim to am­plify each au­thor’s effort by build­ing a new set of tools tai­lored speci­fi­cally for read­ing and col­lab­o­ra­tively cre­at­ing on­line ex­pla­na­tions. We’ve already im­ple­mented a num­ber of use­ful fea­tures. We also aim to build an ecosys­tem of mod­u­lar pages that will make it easy for au­thors to reuse ex­ist­ing con­tent and cre­ate ex­pla­na­tions that can build on each other. We want to em­power our au­thors to write in a way that works best for them, while pre­serv­ing over­all qual­ity.

Fu­ture of Arbital

Cur­rently, we are fo­cused on math ex­pla­na­tions. Even­tu­ally, we plan to move be­yond math to com­puter sci­ence, physics, statis­tics, eco­nomics, health, e-sports, and ev­ery­thing else. One day, you’ll be able to use Ar­bital to get to the very fron­tier of hu­man knowl­edge. Then, we’ll ex­tend the plat­form into one that can foster dis­cus­sions and help all hu­man­ity push that fron­tier for­ward.

If you want to see that day come sooner, you can help! You can con­tribute in­di­vi­d­ual pages, in­cre­men­tally im­prove ex­ist­ing pages by propos­ing ed­its, and craft en­tire ex­pla­na­tion paths. You can also read, learn, and provide feed­back. Each im­prove­ment you make helps the en­tire plat­form.

Let’s work to­gether to build the best ex­pla­na­tion plat­form this world has ever seen!