This Single Rule Underpins All Of Physics

[@3blue1brown]

This was so beautiful. I was thinking of revisiting the old video I made with Strogatz about the Brachistochrone and Johann Bernoulli's solution, but this honestly does most of what I could have dreamed and so much more. Bravo!

[@tanvirzawad]

Peace be on them who follow the guidance. Nice to see you here!

[@ModernWizardx1]

your videos are pretty good 3b1b i always enjoy them!

[@LearningAccount-e5x]

This whole STEM education space has reached completely new heights because of the likes of you guys!!! I couldn’t be more thankful. Stuff like this will be truly world changing. (The hologram video was epic! Long format is incredible and the little secret vlog was the cherry on top. Thanks so much for your work!)

[@JadMustafa]

Indeed, surpasses the limit of education - absolutely beautiful.

[@felix0003]

wowie

[@artbryanmoldon]

Man! Euler is that superhero backup that arrives just in time when all hope is lost!

[@threeuniquefingers]

Indeed! He was like Dr Strange in Avengers Endgame! Summoning Langarange as the ultimate support lol

[@derroz3157]

U LER-NING is the real superhero :D

[@Game_Masters]

14:02 I am like: Not this guy again.. I swear XD THE MAN - THE LEGEND

[@tturi2]

I've already used his stuff in solid mechanics

[@johnimusic12]

Euler = GOAT

[@RENO_K]

"I recognize the lion by his claws" is such an epic quote Imagine being so legendary you don't have to sign off your letters/papers and people instantly know who wrote it

[@joelspaulding5964]

This is quite possible and common in art and music.

[@ahsaasinator2840]

Let’s go another science banger !!!

[@ares395]

@@joelspaulding5964 Try doing that with Science.

[@cgonz8]

Counterpoint: “I have the most beautiful solution. Nobody has seen such a perfect solution, you wouldn’t believe it. You know it, I know it, everybody knows it. Don’t we have the best solutions?”

[@jmalmsten]

That's basically how Richard Bachman was revealed. :P

[@kevinboles3885]

PLEASE, I BEG YOU - continue doing collaborations with Prof. Strogatz!! The combination of TWO of the greatest "explainers" of our time is producing absolutely compelling stories!!

[@TheMoikero]

At university I have heard a lecture about non linear dynamics. Based on his book. It was the best lecture I have had

[@Kyriancdb]

I agree!

[@cocoji3214]

Totally agree with you

[@nolanthedude]

One thing I adore about these videos is that they bring attention to history's forgotten heroes. Nakamura wasn't given the credit he deserved for the blue LED, and that video brought his contributions into the spotlight for millions. Now, Maupertuis has been given the spotlight and he can be recognized for his efforts alongside some of history's greatest mathematicians. If only he lived long enough to see this.

[@entitledOne]

Those things always make me wonder what the people who denied the inventions so hard would say now when they see how much they pushed the world forward. What would the people who insulted Maupertuis for his idea would say after they see it proven right.

[@Player_is_I]

So true

[@sottonk]

Poor Ibn Sahl

[@TheAntira]

I'm not sure I'd call a Nobel prize laureate a forgotten hero

[@julioaurelio]

@@TheAntira The company he worked for thoughout most of his life dumped him and refused to give him the compensation he deserved. A real injustice.

[@raktimaryabiswas3182]

Waiting eagerly for the next part. Please take the least possible time !

[@krishnarajput3515]

but ironically bring the maximum action

[@yarodi]

😂

[@nicezombie8054]

The maximum effort so the maximum work, doesn’t necessarily necessitate the most action, but actually… make it cause the most action

[@drttgb4955]

@@nicezombie8054 Government in the equation = less action.

[@TravisTellsTruths]

Bam ​@@krishnarajput3515

[@DataIsBeautifulOfficial]

Physics is just old guys arguing over who invented the best shortcut.

[@lulairenoroub3869]

"The difference between science and screwing around is writing it down" -A guy Adam Savage was hanging around with. Then Adam Savage.

[@JeffreyBenjaminWhite]

fastest shortcut ;.)

[@lazyphoton]

True, but that's also because nature takes the best shortcut too!

[@XILikeTrainsX]

So trackmania

[@Truth4Lyf]

Math also uses this same principle

[@caifasvaca9451]

The way Euler was described as a “good guy” wanting to help and explain stuff brought tears to my eyes. My old math teacher was a HUGE fan of Euler and his face would light up every time he talked about him. To the point that some students mocked him behind his back for it. That teacher was very much invested in his students and whenever someone, who had struggled with a certain concept, finally grasped it, he would be overjoyed - much more than by someone effortlessly picking things up. If you genuinely worked hard to improve, you would be rewarded with grades on the same level as the naturally “gifted” kids. Only watching this video I just realized that Euler being his personal hero most likely had more to do with Eulers personality traits and empathetic teaching approach rather than his mathematical acumen. Truly a great teacher who had a lasting impact on my life.

[@nokta7373]

Sometimes all it takes is one good teacher who loves and believes in their job to set you onto a path that really defines your life. Wish we had more of those. They are rare and the system doesn't really help finding them and keeping them around.

[@blazedinfernape886]

We don't a lot about Euler as he lived almost 300 years ago. But judging by what we know i am pretty sure he was one the greatest mathematician of all time not just because he produced a lot(and i mean a lottttttttt) of papers but because of his personality. He was probably a very nice man. Being friends with the bernoulli's who were seen as the bad guys certainly helped. He also played with his kids and grandkids and also did math with them! Euler is definitely one of my favorites!

[@ctoid]

It's truly an Eureka moment when all the things just came out to be F=ma

[@happygood18]

Yeah, my mind was blown. I did not expect that!

[@steffenbendel6031]

Actually, forces do not describe all of physics. They are mainly a helper in classical mechanics. But you can not describe interference effects with forces. And in Langrangian mechanics you do not have explicit forces.

[@csgas0]

@@steffenbendel6031🤓

[@Unmannedair]

But it never does describe f=ma... That's just a very special case. F=dI/dt.... di/dt only equals ma for cases where mass is constant.

[@liamweavers9291]

Would it not be more accurate to say force is a function of mass and acceleration? Newton's second law, F = ma, is traditionally seen as a static equation describing force as the product of mass and acceleration. However, life and complex systems are inherently dynamic, requiring a reinterpretation of this law as an interdependent relationship where force, mass, and acceleration are mutually dependent functions over time (defined as Einstein's Co-ordinate Time or the speed of light). Just as the electromagnetic field arises from the interactions of electrical and magnetic activities derived from matter and energy, Force dynamically interacts with mass and acceleration, creating a continuous feedback loop. External perturbations to a system's electromagnetic field influence its internal dynamics, and vice versa, through a process of field alignment at various levels. When matter and energy interact to produce information, or when information is applied to affect matter and energy, the resulting changes occur instantaneously across different field alignments. For example, information interactions at the matter and energy level generate electromagnetic interactions that, in turn, influence the information within the electromagnetic field itself. On a larger scale, the Earth's electromagnetic field interacts with that of the human body, affecting its internal dynamics and maintaining homeostasis-a state of equilibrium. This dynamic version of F = ma, measured continuously over a constant time frame, emphasizes the continuous, reciprocal relationships that sustain complex, living systems, illustrating how fundamental forces and properties are interconnected through time to maintain stability and balance.

[@ahwe173]

veritasium changed my life, from almost quitting school to mechanical engineering

[@AlanTheBeast100]

Then 2B2B should be your math guide (if it wasn't).

[@Waiter1986]

@@AlanTheBeast100 3b1b?

[@gustavosantiago1543]

@@AlanTheBeast1002 bedrooms 2 bathrooms?

[@discursively]

@@gustavosantiago1543 @3blue1brown

jj

[@SochWrld]

Watching this from Nigeria, and it's incredible how i can have access to this quality of information for basically free. I really love the internet sometimes.

[@nemesiswes426]

It is something every person on the planet should have access too. It is the great knowledge equalizer. Allowing anyone from anywhere to learn anything.

[@SochWrld]

@@nemesiswes426 amen to that

[@Gpacharlie]

@@nemesiswes426Elon is working on that.

[@iceteazen]

we need this kind of content to dominate most of the internet.

[@sozzled3053]

The best thing about it… you can look up the different concepts brought up in this as well. It’s the perfect source for going down the “rabbit hole”.

[@vitofodera3615]

I'm a PhD physicist and I'm very grateful to you for this video. I'm amazed, I still have goosebumps. Best explanation I've ever seen. And all physicists and engineers know how difficult it is to understand this topic the first time during college, and you made it so easy. What an amazing trip it was!

[@McBobtheruggaman]

Mechanical engineer here: You took us on a winding journey and brought it all back to F = ma. Subbed for life.

[@Guy-z6o]

F= (far out...or fark all) etc.) we agree.

[@evanmika905]

The long and winding road

[@JEEtube-f5g]

​@@evanmika905 Definitely not the road with the least action.

[@CitroenDS23]

There's a new rickroll in town. We've all been been FMAd.

[@cellofellow5115]

This was my favorite part of my intermediate mechanics course, except in the opposite direction. My professor would take F=ma and somehow turn it into a 2 class multi-page problem that in no way resembles the principles it had built from.

[@MrNpr]

I generally dont leave comments. But I felt I had to write this down. 24 years ago when I took my physics class as a first year under grad student, I was quickly introduced to the Lagrangian and Hamiltonian in a physics class with just the equations thrown around. There were books in the library which provided tons of equations but never the intuition behind them. It was assumed that the reader knew why this had to be the case. I never got back to digging this deeper as my primary area of focus had shifted to other subjects. But after so many years I am finally happy to see the beautiful thought process behind them. Really appreciate you for making such valuable and interesting content.

[@AbyssRein]

Exactly!! Its degrading to teach how to use a formula without the story… the story and attempts through 4+ time periods are rich with lessons that can be applied all throughout life. Stories captivate an audience! Not formulas! Plus, you’ll only find independent thinkers at the forefront of discovery, I wonder how many greats fell short due to the rigidness of curriculum.

[@UniverseSpeck]

I’m 100% with you. I find people tend to learn best through story telling. Not “facts”. Understanding what lead people to a current understanding is far more powerful and sticks with you. It’s harder to do and takes more time and work, but I think it serves more.

[@erikziak1249]

Same here.

[@guigoinz112]

Yeah, I need the story in order to make me abaorb the info, otherwise it’s too stale for my brain to remember😅

[@semsuddin]

This! Wouldn't it be much beter if all of those equations actually started as a story you'd follow through similarly as in this video? Wouldn't be much longer but way more meaningful and easier to learn and understand.

[@xxvimilia]

I love these math videos because its so weirdly satisfying when you introduce another famous mathematician, and I'm like, "My man Euler was in this???". Its the same kind of excitement as the portal scene in Avengers endgame.

[@skoogy7]

They say that theorems are named after the second mathematician who discovered them because the first was probably Euler.

[@robspiess]

@@skoogy7 Euler's got his thumb up in everyone's business.

[@threeuniquefingers]

@@robspiess Euler with his thumb and Newton with his nose poking in every flippin field in math and physics lol

[@matercan5649]

fr, the same mathmeticians discovered everything

[@kallewirsch2263]

First guesses: If it wasn't Euler, then it was Gauss.

[@gabberwhacky]

<a href="#" class="seekto" data-time="1484">24:44</a> I appreciate that you don't shun away from showing derivations. Makes it much more enjoyable for the average physicist

[@madamred3793]

King of confusing for the laymen though😂. Imaging trying to understand this with highschool level understanding of math, I'm no genius in the subject so it was hard to say the least.

[@madamred3793]

But he did a great job of explaining ngl

[@gabberwhacky]

@@madamred3793 I think that wasn't really the purpose. by showing a wall of equations for 5 sec, you don't expect anyone to read it except of sb who hits the pause button and goes through all of it slowly.

[@Krazykahaan]

​@@madamred3793same man. I mean, ik basic differentiation and integration, some standard values, but the derivation for F = ma that he showed made me realise I should watch this a couple years later

[@veritasium]

We debated how to do this. We wanted to show all the math in case someone wanted to step through it, but we didn’t want to get bogged down in it and lose people so this was our compromise.

[@arthurcuesta6041]

I just saw another brazilian watching this video on the supermarket while waiting for his Uber. It was a somewhat old dude with his daughter. You've become massive, man. Great to see it.

[@dpatts]

Q: How many viewers does this video have? A: More than a brazilian

[@ronaldderooij1774]

That was a fun father (NOT).

[@joseivan2337]

Two Brazilians! Guilty

[@kawafernandes7025]

Que legal!

[@aboriani]

@@ronaldderooij1774 If you raise your kids to be dumb, then yes, but my 11 years old daughter and 6 years old boy LOVE watching this and other science channels with me...

[@SalilShahane]

<a href="#" class="seekto" data-time="934">15:34</a> the smile on Derek's face when he was compared to Euler made my day.

[@akarshiaaryan5952]

😂

[@arskiz]

Euler angles

[@realracing3specter295]

👌

[@ludnix]

prof Strogatz was really channeling The Dude when he said that too!

[@Utoxin]

My jaw literally dropped. That's one of the highest complements I think I've ever heard.

[@harananand]

As a Mechanical Engineer I certainly knew the principles of Lagrangian and the Eulerian. I also knew Newton and Bernoulli's story. It touched my heart to learn about Euler's kindness and Maupertuis contribution. I never knew that. The human element was the most special. Thank you for sharing.

[@arunjangir5781]

Yes, me too bro. 😅 its like revision.

[@lawrencerisley7231]

As a carpenter that watches math videos - knowing little about advanced equations - when I saw the outline of his profile it piqued my interest. I said to myself, "cool, he's back. There's something special about the E man." To discover he's also kind and generous, sorta made my day. Thanks Derek.

[@Just_A_Dude]

Maupertuis is, I feel, a guy that saw Bernoulli's work and had an intuitive vibe, but wasn't quite able to put into words correctly. People like him are invaluable for the process of discovery and creation, but hardly ever get the recognition they deserve because they're not the ones that bring it home.

[@dangerfly]

@@Just_A_Dude People want to feel special by worshiping special individuals when advancements are always built on top of the previous shoulders. It's shoulders all the way down...

[@user-gr5tx6rd4h]

I have read that Gauss (according to Niels Henrik Abel, 1802 - 1829, a very short life) did not have Euler's kindness of writing clearly understandably, but rather like a sly fox who uses his tail to remove his tracks. Gauss: ".... Thus it follows, obviously, that ...", and you need 8 hours (or perhaps 5 days) to see the "obvious"...

[@paulatk44]

A very fascinating video, this brings back painful memories which i have been enduring. My relationship of 6 years ended 3 months ago. The love of my life decided to leave me, I really love her so much I can’t stop thinking about her, I’ve tried my very best to get her back in my life, but to no avail, I’m frustrated, I don’t see my life with anyone else. I’ve done my best to get rid of the thoughts of her, but I can’t, I don’t know why I’m saying this here , I really miss her and just can’t stop thinking about her .

[@JohnWicked-fx3cs]

Parting ways with someone you deeply cherish is an agonizing experience. I understand firsthand, having encountered a parallel situation at the end of my 7-year relationship. Driven by an unyielding determination, I explored every avenue to salvage our bond. Seeking guidance from a spiritual counselor proved pivotal, as their intervention played a crucial role in rekindling our love.

[@paulatk44]

That's fascinating! How did you come across a spiritual counselor, and what's the best way for me to contact her?

[@JohnWicked-fx3cs]

Meet Suzanne Ann Walters, an outstanding spiritual counselor with the power to restore your relationship with your ex.

[@paulatk44]

I'm grateful for this valuable information; I've just taken a moment to find her online.

[@Kampamba]

I’m a practicing mechanical engineer of 6 years now. Nearly 30 years old. In 2014 I discovered Veritasium and Smarter Every Day when deciding what to study. I cannot explain how instrumental these videos have been to my life. Thank you so much Derek!! Humanity is better off because of you

[@elementalist1513]

Im in school for engineering, but we haven't talked about this topic at all. Would this principle apply to classes like Dynamics and make it easier for me😅

[@offabender2719]

​@@elementalist1513You do generally cover it, idk in how much depth, it depends on your course structure and discipline. But if you ever take an advanced dynamics subjects you'll encounter them especially for shafts and machines with linkage mechanisms. Although nowadays most of this stuff is taught in conjunction with computational methods not strictly rigours math (at least where i study eng).

[@thegr8malachite370]

2 of my favorite science channels! add tom scott to that and we're set 😊

[@st0rysphere]

Veritasium has now surpassed the quality of netflix docementaries. Really one of the best videos on math i have ever seen. Well done Ve. Cant wait for part 2

[@Neverforget71324]

Agree. A few years they did a reboot of "Cosmos" ... The production quality of these videos is at least as good as the Cosmos series.

[@jmalmsten]

Netflix docus really have fallen lately. Moving more and more towards the formats of cable TV to desperately stretch out every single minute of content 3-6 times longer than necessary.

[@jerrysoncallado8709]

Im still waiting for the part 2 of their video about Thermite, and now Derek is making me wait for the part 2 of Action. They better release these sequels soon because im loving it

[@Patterner]

too bad for netflix my first thought will always be "black Cleopatra"

[@andrewandrus3296]

Imo these have always been better

[@Lukav1]

This is such a great transition: Mapertui is bullied - depressing music playing Euler mentioned - Boss battle music starts playing 🔥🔥🔥

[@LuisSierra42]

Epic fight ensues

[@One.Zero.One101]

It's like when the battle theme starts playing in Final Fantasy.

[@ethanboulter2883]

Please never stop making videos! You and your team make some of the best science communication content out there. Veritasium provides the education that public schools fail to do.

[@StarFury2]

16.5M subscribers, and still not afraid to show entire formula deriving process using calculus! Bravo!

[@DanKaschel]

I wish he'd taken the time to impart a bit more intuition to those of us who haven't done calc in a long-ass time. But I'm certainly glad the rigor is there for those who can fully appreciate it.

[@jackkerouac1523]

Gay comment

[@DanKaschel]

@@jackkerouac1523 oh noooo incel doesn't like the comment nooooo

[@fernandoizaurieta7270]

I'm a theoretical physicist, and I'm astonished by how precise and well-presented the video is. It reminded me of the wonder I felt as an undergraduate attending beautiful lectures on classical mechanics. Thank you for creating such wonderful material for everyone on KZbin.

[@asjordan0yt]

Here, here.

[@isodoubIet]

Shouldn't a theoretical physicist know that the central claim of the video is completely wrong?

[@Dragrath1]

@@isodoubIet If you have data to "prove" that the principal of least action is wrong then do so but until then this forms the principal foundation of not just all of classical mechanics but the Feynman path integral and quantum field theory i.e. the standard model of particle physics. The burden of proof always falls onto the claimant when the weight of all human progress and knowledge in physics is at the heart of the subject.

[@isodoubIet]

@@Dragrath1 The principle of least (stationary) action is not wrong... _in classical physics._ It doesn't apply in quantum mechanics. In fact, quantum mechanics is what you use to prove exactly in which sort of situations the principle is a good _approximation._ The video goes so far as to state that quantum mechanics can be replaced by the least action principle, which is categorically nonsense. "but until then this forms the principal foundation of not just all of classical mechanics but the Feynman path integral and quantum field theory i.e. the standard model of particle physics" That is nonsense. Pop quiz! Explain in your own words how dimensional regularization is used to treat infinities arising from loop diagrams, why that doesn't present any conceptual problem for the theory, and why dimensional regularization is advantageous when compared with more simplistic schemes like cutoffs.

[@Dragrath1]

@@isodoubIet I thought you were trying to say the principal of least action was wrong, and yes the mechanical form of the action breaks down in quantum mechanics but the Feynman path integral shows quantum systems still follow the principal within probability or state space. I don't think you can really say that the Feynman path integral isn't part of the principal foundation of the standard model given that Feynman diagrams which are a computational tool for calculating these systems of possible interactions depend on this theoretical framework At this point though I think there is good evidence that this is a consequence of deeper more fundamental rules with Wolfram's computational emergent model of physics as a consequence of Turing complete computational constraints simultaneously iteratively acting on some informational system looks promising if they can come up with a solution for computing the continuous domain of dimensionalities which appear to be natural in that framework.

[@funnyname7773]

As a first year physics student, these types of videos are incredibly valuable! I legitimately cannot explain how incredible it is to walk the line of simple explaination vs specificity and detail that you and your team walk perfectly. Thank you so much, it makes me so happy that there are science educators such as yourself following in Euler's footsteps, teaching with empathy, clarity, and clear passion!

[@leviathan5207]

The video is interesting for sure, but it is technically little more than a history lesson. I wager you would not be able to solve even the simplest of problems using the fucntion you probably just saw for the first time in your life, after watching this video. Calling him a teacher for giving you a history crash course on a single formula is a disservice to anyone who is actually teaching, I think.

[@funnyname7773]

@@leviathan5207 While I understand where you are coming from, I never meant to undermine or disparage classical teachers and educators with my praise of Veritasium. Rather, and this was unstated, so there would have been no reason to assume this, I meant to call attention to the benefit of having various avenues and angles to education. To be sure, I am pursuing physics first and foremost because I had a fantastic high school physics teacher who ignited my initial passion and you are most definitely right, I likely would not be able to solve most simple problems using the function without help. However, I do not think that the value that Derek and his team provides is that of immediate practical application of the mathematical concepts they cover. Rather, as stated by many other people much smarter than myself, by teaching the history and rationale behind these mathematical concepts, one can make sense of them outside of just calculus and algebra. Additionally, I am calling Veritasium a teacher because, over the past couple years, I have learned a lot from this channel. I think that classical teachers are incredibly valuable (and often undervalued by most people), but I do not think one has to teach in a school to be an educator.

[@emm6064]

@@leviathan5207 my father tried to teach me to drive stick without explaining the principles behind it ("just do what I say when I say it"). Fortunately, he was a fast-hand on the emergency brake and I got to autograph the the skidmarks in our driveway. 🙂 Mom took over after that and learning what was happening in the engine as I pressed pedals kept that from happening again. Knowing _why_ helped me learn about "how". Having a conceptual underpinning and an understanding of how a concept was _developed_ gives you a framework to attach all the specific mathematical details to; something that simply throwing the final equation at you wouldn't provide. Context matters.

[@aitsfni]

​@@leviathan5207 I am also pursuing a physics degree. I'm in third year. While a large part of physics is, indeed, knowing how to solve formulae for solutions, simply knowing how to plug in numbers/manipulate an expression pales in importance compared to actually understanding the concept at hand. Where the equation comes from, what each term means, why certain cases yield certain solutions, etc.. Without this knowledge you are no longer doing physics, just math. Videos like this are invaluable when it comes to forming intuitive foundational understanding of these topics. Setting it all against the backdrop of the real history of the development of these concepts and ideas surely helps connect everything together. Also, Derek is Ph.D. in education research. I'd wager he knows more than most when it comes to education.

[@funnyname7773]

​@@emm6064 Wow, what an eloquent way of putting it, thanks!

[@ninjaasmoke]

<a href="#" class="seekto" data-time="1546">25:46</a> when i realised what was coming, my mouth was wide open in disbelief! science if freaking beautiful! and how you present it is awesome!!!!!

[@notenoughmonkeys]

They should make a movie about this, Least Action Hero.

[@vids7983]

You talking about anime earth? Haha

[@garybaldrick]

@@vids7983I think it’s either a reference to the movie Last Action Hero or the title of their sex tape.

[@RolandoGarza]

Would the villains stumble and hit their face on Least Action Hero's fists?

[@Gogeta70]

@@RolandoGarza Yep, their faces would find the quickest path to his fist, every time.

[@-unclebuck-]

@@vids7983 Last action hero is a movie.

[@roodog1]

I took a class called theoretical mechanics, where we learned most of this. What was explained to me over 10 weeks was described infinitely more beautiful in this 30 minute video. I’m tearing up just thinking about it. Your channel is absolutely incredible for bringing math and physics to the average person, and even making the people familiar with the material think about it in a new way. Thank you

[@G36-999]

damn literally same here

[@backspace345]

Last semester theoretical mechanics ended for me. I thought Lagrange's mechanics was just yet another way to describe moving things, except even more generalized and even more boring. I still do find it unintuitive, and i was genuinely hoping to see how this pops up somewhere else, but sadly we must wait for another video.

[@Luicatus]

​@@backspace345 Funny Lagrangian Mechanic saved me in my first Semester of theoretical physics. Could not get the hang out of classical Mechanik, but this gave me at once a tool set, i could appy. Esp. Double Pendulums (practical example: swinging bell) That and the Maxwell Equations are still the only parts of theoretical physics I like as a applied and Experimental physicist Even 20 year later and out of the scientific world

[@gd1037]

Personally, watching this 30 min video made me wish I had time to study the subject over a 10 week course. These videos are nice to learn about the history of physics, but if you don't study the math behind it you don't really understand any of it. You just accept an answer for the correct one.

[@manuel0578]

No it doesn’t. You’re not going to be able to do any calculations yourself after watching this video.

[@DevRajyaguru-lx8pi]

A beautiful mix of history, physics, math, music, emotions and story telling. I am just blown away ! I remember terry tau's quote at this point that, we should teach our children the history behind the things, how it came and how much effort went to bring it in the form it is today. If we don't appreciate history then there is no way we can appreciate it's true essence. Thank you Derek and the team for their amazing efforts in STEM.

[@Neverforget71324]

100 percent agree. I was always frustrated in college because I felt I was never "catching on" quickly enough... only to find out years later that the knowledge we were taught in one semester took humanity hundreds of years to figure out.

[@chattiezzz]

couldn't agree more!!

[@kirkbotingress3690]

I hated history class because it seemed to be about learning these dates and names of dead people. Nowadays I love history because I can ignore exact dates and focus on the reasons and motivations of those people that came before me

[@aseemlimbu7672]

@@kirkbotingress3690 Loved the way you put it.

[@btf_flotsam478]

It's worth noting that the history of a field is often more understood by those in its field than most historians. As a mathematics person, I have already heard of the Maupertuis, Voltaire and Frederick the Great drama from a biography of Leonard Euler, and have discussed the history of probability with professors while doing my honours thesis.

[@mariamabdallah-u5x]

Your video deeply moved me, I have been wanting to go back to learning physics for a while now and your video reminded me of the sense of wonder I had in my freshman year. Thank you for creating something so special, I can’t wait for future videos like this one!

[@skindalal1189]

This Comment is for Maupertuis.

[@FScott-m1n]

_pours one out for Maup_

[@lordbunbury]

I did it all for the Maupie

[@kilgorezer]

hi

[@mattmccallum2007]

If you say his full name in a dark room four times fast…… you giggle

[@henrikebbesen1838]

The unit [kg*m**2/sec] of m*v*s ought to be called a Maupertuis, 1 Ma.

[@tonytya]

I attended a university lecture which covered Multi DOF Dynamic Systems, the Euler-Lagrangian Equation, and Double Pendulums this morning as a Mechanical Engineering student. Was completely baffled and confused about the theory behind all of it. Coming home exhausted at the end of the day watching this piece of art just made me tear up. Such an amazing coincidence that this video was released today. The moment everything came to F=ma was such an Eureka moment too! Thank you Derek.

[@kzeich]

It's beautiful

[@tatsga]

I just had 8 weeks of my first course of mechatronics in technical university and this video was some what eye opening. I have been struggling with concepts of virtual work etc used in very hard and tidious matrice calculations used in equations of motion on multibody systems.

[@whatTheblue]

Only if uni teachers were like this!!!

[@blu_sevn]

As a physics student in the 3rd semester this is a brilliant video to watch...literally goosebumps all the time. It is so satisfying to see what u have learned being illustrated in such a way. Just WOW really

[@ashleymorrissey101]

I've been out of my engineering school for over a decade, but this video brought me back to my youth, lol I don't remember how to do all this math anymore but I recognize it and I think of my friends that went into math and physics

[@realracing3specter295]

i always get goosebumps when i read about all those mathematicians, as they always somehow related to/connected another great mathematician, which i had no idea belonged to his timeline... and also contributed to the theory 🤯🤯

[@Pleasing_view]

Have you done Mathematical Physics yet?

[@blu_sevn]

@@Pleasing_view just theoretical physics

[@acron7559]

I am a computer science student, i have a special place for physics, even though I left it for 4 years. This video revives those good ol' days.

[@wissamkadamani]

I really love it when I watch a veritasium video, because one of 2 things happen: 1) The content is completely new to me extremely exciting to learn 2) I already know most of what's about to be said and I'm pausing and predicting what Derek will say next. It gives me a new perspective with some wholesome details, and a nice ego boost. This was one of the latter, and it's an absolute masterpiece of production value. FLAWLESS

[@priyobayuramadhan1284]

<a href="#" class="seekto" data-time="1712">28:32</a> I remember when I was doing highschool physics olympiad, we treat Lagrange equations as some short of legendary weapon to handle meticulous oscillation problem 😂, because it is so hard to get the equation correctly using newtonian method. But we never knew why does it work and where does it came from. My mind has been blown 🤯.

[@J.E.E.DESTROYER]

Very cool 😎😎

[@fredericharmand]

It is easy to understand why this works. In the Langrange formula, the potential V is the cause and the energy of motion, the kinetic energy T, is the effect. The difference between the two must be zero all along the integration path, otherwise it means that we have missed either a cause or an effect, or both. Basically, the philosophy is that for every cause there is at least an identified effect. It is like the Newton law F is the cause and the acceleration is the effect, both are equal. The problem is that the Lagrangian assumes instantaneous transmission of causality, which is why it does not work in relativity. In Relativity the causality takes its share.

[@Player_is_I]

Lol, now it is when it makes sense right

[@sanidhyapratapsingh-h7d]

@@fredericharmand what does "instantaneous transmission of causality" mean, and what's different in relativity when this doesn't work.

[@fredericharmand]

@@sanidhyapratapsingh-h7d "Instantaneous transmission of causality" means that there is no delay between a cause and the corresponding effect on a body. This is not the case in relativity.

[@aseemlimbu7672]

The most beautiful thing about Science and Mathematics is you can just say "I don't know" for the thing which you really don't know and it doesn't impact your stature.

[@JoshuaNorton]

Ah, no. That's actually really far down the line. From my experience in university, the freshmen do like to play out the historic tropes of quarreling scientists fighting for each shred of credit. There are a lot of loner types entering maths and physics who are on a mission to show that they are the smartest. The way I experienced it, the physics course is deliberately structured to socialize such types of students towards a team spirit.

[@user-gr5tx6rd4h]

@@JoshuaNorton That must be AMERICAN students, I guess!

[@DanKaschel]

​@@user-gr5tx6rd4hmy friend, you have much to learn of human nature

[@MyNameIsSalo]

@@JoshuaNorton I studied physics in Australia and didn't get any of that. No one really cared how smart you were or how well you did, people just wanted to get through the day and hit up the bars. Also like half of the students were asians that only spoke broken english and kept to their own social groups, and that is half of an already very small class because not many people take physics. The asians were always good to get answers from if you can communicate with them though, much smarter than us and none of us even cared or tried to compete. We just wanted to pass

[@Beryllahawk]

My son sent me to watch this. I'm already subscribed but so frequently when it's physics I get a bit wary, I'm very much not a maths person. You start throwing equations across the screen and my mind often just quits right there, lol. But this was fascinating. When he told me the name of the principle I blinked at him and said "You mean conservation of energy?" and he started hopping up and down going "NO! That's just the thing! Augh, go watch it Mom!" SO here I am! And I see what y'all are saying. Interesting to think about and I look forward to the next one!

[@meghanto]

this is so nice to see! thank you for watching and sharing his enthusiasm!

[@DJTubeFactory]

Welcome. The next video will be interesting.

[@gustavderkits8433]

Two thumbs up. Best explication of the principle of least action I’ve seen. Should be shown to classes in classical mechanics.

[@pedrocasella1327]

I just did an undergraduate research about Lagrangian in manifolds, and now I have to create a poster about it. Thank God. for this video right now!!

[@PetraKann]

So you were asleep in class for all those years?

[@Gokuk-oq3uk]

@@PetraKannwodent this video make his task easier

[@roulzhq]

Bozhe moi

[@rasmusturkka480]

@@PetraKann yes, studying is for nerds who don't know anything

[@PetraKann]

@@rasmusturkka480 listening and paying attention is not

[@MasterReady12]

Initially I was skeptical of the clickbaity title and the intro, but just after 3-4 minutes I was so *indulged* in it that I forgot to increase the video resolution to 1080p like I always do. Only later I realised that I watched 30 minutes of video that I was not going to watch. This is a testimony to how great this video is.

[@DornigeChance]

Do not think that you are a meassurment instrument for video quality! But I see what you(!) like.

[@Egan466]

I have a plugin that auto set to highest quality all videos because KZbin doesn't like anything above 1080p

[@PROtoss987]

Same for me. I was going to watch this anyway because Veritasium always delivers, but I thought I'd put it to later and store the tab for a later day. But I saw a math equation, was intrigued and kept watching for a bit, then it was so interesting that pausing wasn't even on my mind.

[@ryukiiprimer5383]

You should watch Derek's video on clickbait and why his video's title and thumbnail seem clickbaity when you'll actually get what you see.

[@HunsterMonter]

It sound like clickbait, but it's true. Literally all of modern physics are derived from either lagrangian or hamiltonian mechanics, both of which are founded on the principle of stationary action

[@niccolozanotti]

Physics graduate here. You brought back a lot of good memories from my analytical mechanics course. I wasn't really able to appreciate the beauty of the principle besides its mathematical elegance. What you (and Strogatz) are doing with these videos is truly a gift to humanity. Thanks

[@matercan5649]

The animation in these videos keep getting better and better, I love it.

[@nclsb142]

Yeah It's a great addition to the content 😊

[@theairaccumulator7144]

Am I tripping? It feels like I've seen this exact video before. Years and years ago on 3B1B. Did they just recycle the whole script and animations?

[@cherriberri8373]

Yes, just let that production value keep convincing you to never be skeptical of watching these videos.

[@kilimanjarocruz660]

For me, one of the best introductions (albeit a bit old-fashioned at times) to the principle of least action is Landau and Lifshitz's volume on Mechanics. They also properly give Mapertuis his share of the credit. Also interestingly, they go on to explore how the equations change when you relax the constraints a bit (for instance, by not fixing the final point) and what this teaches us and how to use it. Simply marvelous.

[@PrajwalDSouza]

One thing missing? Connection to Noether's theorem. It is right there. Variation of momentum over space (Lagrange) vs variation of energy differential over time (Hamiltonian) <a href="#" class="seekto" data-time="1310">21:50</a>

[@perorenchino2036]

Convert to hinduism

[@hata6290]

maybe next video

[@srujankumarmishra1768]

ricebag

[@toinfinityandbeyond2023]

Hi Sir... I am Pranetha(remember from CFAL 2021 batch,druhan and pannaga's classmate in case you dont remember)....because of you I am still watching veritasium...currently in NITK final year ....hope you are doing great

[@PrajwalDSouza]

@@hata6290 yes. I realised that towards the end. Hope the video goes deep into this topic. Also, especially symmetries.

[@diegopg7186]

This channel is the first source that has taught me the origin and meaning of the Principle of Minimum Action in an intuitive way. I can only thank you for spreading so much knowledge. Long live Veritasium.

[@johnchessant3012]

<a href="#" class="seekto" data-time="841">14:01</a> Euler!!

[@Weeksmistro]

Euler came in and said: “On your left.”

[@ngcool4112]

Oiler

[@somethingforsenro]

when euler's on your side, you know you're right. god damn

[@Miftahul_786]

<a href="#" class="seekto" data-time="1553">25:53</a> I can’t lie.. I may or may not have gotten goosebumps

[@plwadodveeefdv]

dam right when there's an emotional crescendo in the music? that's crazy

[@marwanfakhradin2543]

I certainly did

[@PinkeySuavo]

To be honest I wasn't shocked. I won't ever call myself to be smart, but I looked at this this way: if we initially use some formulas, isn't it normal that we can manipulate it to the already known equations? The "m*a" already popped out in integral, just "a" was written in terms of second derivative of displacement. I just think it's kind of rewriting the same thing in different terms. If you take a look at 24:45, they started with (1/2)*mV^2. It is already strictly connected to F=ma.

[@Miftahul_786]

@ Yeah yeah I get that it’s just beautiful to see it in its final form and with the crescendo of the music it was just 🤌🏼

[@ALJCpalaeozoic]

I studied this as a third year physics undergraduate and you've really captured how at first it seems like pointless pushing algebra around until suddenly a profound revelation hits you. Our mind-blowing moment was the professor going on to show how you could picture every possible path between two end points as waves with neighbouring paths destructively interfering everywhere apart from along the true path where dS = 0, where the paths would be in phase. All of a sudden a ball moving under Newtonian motion looked a lot like a quantum mechanics. Eagerly waiting to see where this goes in the next video!

[@solconcordia4315]

Maybe it should be dS = h instead of dS = 0. Euler might have made the initial error which led to the disagreement between quantum theory and relativity. The two may very well be in the analogous positions as the Rayleigh-Jeans and Wiens law formulas in the Blackbody radiation spectrum distribution plot. Both are accurate within the domain of applications but cannot bridge the gap. General relativity uses space-time continuum but quantum theory uses discretum of eigenvalues. Maybe space-time continuum of general relativity is incorrect but quantum theory's discretum of quantum states in the energy-momentum discretum is correct.

[@scotth.hawley1560]

Great timing! This is precisely what we're covering this week in my mechanics class. Assigning this video as required viewing.

[@MrAnshulji]

Gripping screenplay ✔ Cinematic background score and camera angles ✔ Cameos by renowned (but dead) mathematicians ✔ Three-act structure, with the introduction of Euler's character placed perfectly at the mid-point of the video ✔ Spooky Halloween theme for the season ✔ Post-credit scene hinting at a sequel ✔ Forget blockbuster Hollywoood flicks, instead this video should be released in theatres and sent in film festivals!!

[@thehardistdifficulty1050]

We need more like you good person ❤🎉 math and science are everything ❤️ 💖

[@LynxUrbain]

And what a cliffhanger at the end !

[@jamesmiller1770]

Not one single channel on KZbin can give you such detailed, contextualized and informative, yet so easy to follow and beautifully arranged video on what would seem to be just another part of curriculum you would go through in school or university. This makes me want to learn more about this topic, physics and everything in general which means this channel has achieved the true meaning of teaching. Inspiration and imagination. Kudos!

[@DanKaschel]

3B1B. And that channel knows its audience better, imo. This was a cool video though.

[@the_spicy_orange]

@@DanKaschel 😂 That's who I was gonna say.

[@nephi246]

Kursgesagt is amazing like that too

[@mugnuz]

@@nephi246 kurZ*

[@nephi246]

@@mugnuz Kurzgesagt*

[@bernard0camp0s]

Man, seeing what all these geniuses were up to way back when, sometimes in their spare time, is truly humbling.

[@ultraokletsgo]

My understanding is they were fighting off bears a lot of the time.

[@SnackPack913]

I remember this blowing my mind when we learned about it as a physics undergrad. These days I forgot most of this but had always thought if it as “lagrangian mechanics” since it used the lagrangian. But now I distinctly remember a chapter on Hamiltonian mechanics. Man I miss those days where ever single lecture just completely blew your mind. I suffered through learning math just so that I could have the tools to learn more physics

[@benjamincraig7198]

This video made me pick my Feynman lecture series book back out. The mathematics of all this is calculus of variations. I taught myself this once, and it was one of the most profound insights I’ve ever had mathematically. Thanks Derek, you are truly this days Feynman in terms of making complex concepts approachable and fun!

[@דודקופלוביץ]

Expect Feinmann to make an appearance in the sequel video.

[@ivanjelenic5627]

As the previous comment to your comment said, you wouldn't want to miss the next video then.

[@wag-on]

Definitely a path integral on its way.

[@InAMinMaths]

Definitely getting QED vibes here

[@Help-jr1mq]

<a href="#" class="seekto" data-time="1538">25:38</a> you know it just got real when music changes

[@glengarryglenross7127]

No - it's the words 'but wait'

[@Conormedy]

😂

[@kingdolphin510]

As of late, with each video you release I am struck by the sheer integrity and production value of your work. Since I discovered this channel I have been thoroughly impressed with your videos, but with each successive one you somehow still manage to reach new heights. It's not just production value, but also some other intangible factor I lack the vocabulary to express that gives your videos their unique and unmatched quality. I would not call it an exaggeration by any stretch to say that you are one of the greatest educators of the modern era.

[@Pritchie45]

<a href="#" class="seekto" data-time="1156">19:16</a> This is when I got lost.

[@architektradim]

Same. Did he mean the sum of areas constrained by trial path above and below the true path is zero?

[@inksansdemon5181]

same.. not quite sure what they meant on that part🤔

[@cursedlycan9925]

Its Simple integral calculus. And a few classical mechanic's formula for Kinetic and Potential energy

[@architektradim]

@@cursedlycan9925 And how about the part when visible difference becomes zero difference?

[@bazylicyran7727]

Same here. In fact, I think I'm lost even a bit earlier: "So if you took a tiny step to the left or the right, the value of the function basically doesn't change". What does that mean? So does the value change or not? I think it does, I don't see why it wouldn't. And then, if you were to change the path of least action by "adding a tiny bump here or flattening it out there", why "the action basically shouldn't change"? It seems obvious to me that it would change. They even say a few moments later that "any other path must have more action". So why this altered path doesn't have more action? I would really appreciate an explanation.

[@RitikMaurya07]

Now I understood how my dog feels when I talk to him.

[@AdithiaKusno]

When Veritasium summarized Physics Grad first semester in half hour! Impressive work, you literally summarized the first semester of Physics Grad lecture series in one video. As Richard Feynman said great teacher knows how to communicate complex subjects in the least amount of action. Impressive! Even second semester on Thermodynamics, third semester on Electromagnetism, and fourth semester on QED would be extra episodes on least action principle topics. I am guessing eventually Veritasium might show how the least action principle works on Einstein's General Relativity. It's KZbin channel like this that helps me explaining Physics to my kids. Thank you Veritasium.

[@cherriberri8373]

Your first sentence should be a giant red flag to you. If you are capable of critical thought, so much info being compressed into 30 minutes should be a red flag that the info is at minimum, incomplete.

[@nikhilgupta5733]

The best explanation I never thought I would get for the action. There I was studying in the lecture hall for the first time, thinking why it is not intuitive, what i am missing. Thanks for reminding me why I always loved Physics. Cheers!

[@akhasshativeritsol1950]

I love Strogatz! I was fortunate enough to take his class on nonlinear dynamics and chaos, it was the most interesting class I'll pretty much never use!

[@marvelwizalamu598]

Words cannot fully express how much this channel has transformed my perspective on learning. There are times when I feel completely lost with the concepts he talks about, yet instead of feeling intimidated, I’m inspired to watch the video multiple times and seek additional sources to deepen my understanding. The passion and effort he puts in helping people understand makes me not feel like I'm too dump to understand such complex concepts; instead, it sparks curiosity and a genuine hunger to extend my knowledge. I really appreciate you team Veritasium

[@mikec.8604]

same for me !

[@mikeyb7263]

The twinkle in Einstein's eyes was no accident.

[@oberlurch-handimations8628]

The thing I love the most about science is that it's like a cooperative undertaking spanning thousands of years

[@farrel_ra]

Agree

[@Argoon1981]

Indeed, even Newton said "If I have seen further than others, it is by standing upon the shoulders of giants.", so no important mathematician, physicist or scientist (or natural philosopher, how they used to be called) has single handily invented or discovered anything from scratch, all discoveries in physics has been a human group effort.

[@aldrinmilespartosa1578]

@@Argoon1981 man, imagine these poeple who are separate in time in the same room.

[@samagraarohan2513]

cooperative for only as long as no one brings up a challenge to the views

[@donmacquarrie9161]

Giants standing on the shoulders of Giants....

[@yashchaphekar8223]

this video is pure gold for anyone interested in physics man!

[@prithvibharadwajmellacheru1121]

I've experienced bliss by the end of the video. Feels like it filled a small void in me that was present from the time I started using the Lagrangian formulation at school, as I was busy on the practical applications but never really took time to explore the reasoning. Thank you Veritasium

[@deanjericevic8912]

Teaching school physics for over 30 years I love how you have embellished the maths & physics with the history of those men who contributed to the theory’s development. A coruscating delivery; your presentation makes it so interesting that there would be so many more physicist & mathematicians by teaching that way. These optimisation problems solutions are found in the "Calculus of variations". Like a chain hangs freely its shape is derived as a hyperbolic cosine curve or a hole drilled through the earth from one side to the other & a ball dropped through it to minimize time is a cycloid. The shortest distance between 2 point! Yes, one of the simplest problems takes such complex maths technique to solve it!

[@Zibonnn]

Veritasium's most impactful aspect is Derek and his team's storytelling and visual presentation. I'm not a math person, and I never have been, but you still keep me watching your videos from start to finish! If I had a math teacher who could explain like this, I’d probably be good at math.

[@wendjys566]

I love how u are slowly getting more detailed in ur explanation and showing and proving the equations This was really beautiful

[@noddynorthside]

How satisfied would not Mr Maupertuis be, were he still alive, if he could see the principle of least action applied to highest degree of dignity to which it is susceptible.❤❤❤

[@AyoolaLadapo-hg7vs]

I wonder who Not Mr Mapertuis is?

[@AyoolaLadapo-hg7vs]

@@noddynorthside Just a joke bro😂🤲

[@noddynorthside]

@@AyoolaLadapo-hg7vs 😅😅

[@natetrice8194]

Literally did the cycloid problem in my intermediate mechanics class yesterday. The timing is crazy!!

[@paulbizard3493]

... They are among us ...

[@adnan7698]

You mean the timing is optimal?

[@aqibramzan9742]

Me too

[@Flesh_Wizard]

​@@paulbizard3493amogus

[@HeisenbergFam]

You know its deadly serious when Veritasium says "we are approaching spooky teritory"

[@0Senzuu]

😂😂😂

[@DrDeuteron]

"spooky" is such a loaded term in physics.

[@giovanni_vaz_cardoso]

​@@DrDeuteronEinstein effect.

[@dVTHoR]

I think this was a meant to be a really funny double meaning line, since in real life we are very close and approaching Halloween. If not, that is a hilarious coincidence.

[@naejelangelogonzales6623]

Ghosts are explained by physics from this video right now😊

[@mage1over137]

The units of action are the same as Entropy, which in natural units is unitless which is the same as information. When doing Quantum Field Theory, Action is the phase of the path integral. I think there is a deep connection between least action and the 2nd law of thermodynamics.

[@LuisBrudna]

Yes, entropy comments on the spreading of energy and the tendency of this spreading to be maximum and reach a culminating point of maximum at equilibrium. More or less like a ball that goes down the ramp described in the video.

[@muhammadsheheryaarghayas2968]

This has to be the best and most expansive crossover ever. Spanning over centuries of eras, involving almost every major mathematician, uniting various branches of maths to solve multiple problems over many fields, creating a unique new unit which sparks innovation for an entirely new and uncharted area of physics. BRILLIANT! I was legit fanboying over the entry of every mathematician and the reveal at the end equating to Newton's Second Law of Motion had me actually pause the video to really scream and grasp the mind blowing connection. Amazing work by Derek and the amazing Veritasium team. As always, awesome work and thank you for this masterpiece.

[@crazypyro777]

Having a mathematician say you are like Euler must be one of the highest possible praises.

[@natyalim]

Probably one of the best science videos I've seen. So much where one can see where the math originated. Seeing the history of it is extremely fascinating and helps understanding it. Would have been interesting to see something like this in high school or the university to gain a deeper understanding.

[@TheThoughtfulInsight]

When I studied these topics during my college major, they didn’t impact me the way they do now. I’m just flabbergasted at how simply you explained such a complex problem in modern mechanics-it blew my mind!

[@iamsh4r106]

<a href="#" class="seekto" data-time="29">00:29</a> compression going crazy lmao

[@lazymidas4262]

😭

[@0maeWaMou]

What're you even talking about

[@Wm7forthewin]

@@0maeWaMouthe million ducks

[@0maeWaMou]

​@@Wm7forthewinelaborate

[@Brunoenribeiro]

went brrrrrrrr

[@nmpspiky]

<a href="#" class="seekto" data-time="22">0:22</a> bro, am I the only one who thought this video is about Entropy? After seeing del (S) = 0 😂 Entropy generation for reversible adiabatic process

[@guilhermefavaro2089]

I thought too 😂

[@RaushanKumar-qb3de]

Universal

[@MansukhchainSingh]

Me too

[@Edarnon_Brodie]

Yes you're the only

[@CalculusSince13]

Thanks for the video! It gave me an insight into Lagrangian as a high schooler in the final year. My Physics teacher once briefly mentioned about Lagrangians in class, that they’re a technique used to tackle mechanics problems using energy, and now I see exactly how! I can’t wait to learn more about this in detail in college next year!!

[@markus9147]

I love these types of math/physics history videos. They really put in perspective that we are standing on shoulders of giants. They also make me nostalgic about the time I was learning these things in college for the first time.

[@TherapyGel]

It also really humanizes these figures, at least for me. We were all taught that Newton was a genius and the impact of Euler's work. But hearing about the social dynamics between these people and their relationships really brings them down to earth and reminds you that they were just people. Brilliant, yet flawed people.

[@whyandhowdaushitenande]

<a href="#" class="seekto" data-time="1565">26:05</a> why this feels like an avengers movie , when every hero is defeated and we feel lost but then that one hero out of nowhere comes as an savior , the geniuses of Newton , hats off to my guy maupertuis, and shout out to euler and lagrange truly one of homie , wish i was part of this gang.

[@arktic3140]

The principle of least action genuinely is one of the most underrated theories when it comes to explaining general relativity. Thank you so much for exposing more people to this theoretical masterpiece ^^

[@javieramado6839]

This video made me cry. Greay job explaining not just the physics, but also the history around.

[@troik]

I started watching Veritasium 13 years ago about a Slinky dropping and we're now here with pretty complex formulas (for me), I feel like Derek is giving us a STEM degree without us even noticing. I learned so much in these 13 years. Thank you.

[@cherriberri8373]

You need to stop implicitly trusting people simply because they appear to know what they're talking about and have a higher production value. Veritasium does not make very trustworthy claims.

[@philipingram1563]

Such a mental journey, awe inspiring...

[@dog4me]

@@cherriberri8373what is bro smoking?

[@DootyDuck]

@@cherriberri8373 im not saying you are wrong with the advice about not trusting people just because they appear trustworthy, but could you give me an example of Veritasium making untrustworthy claims?

[@Tjeran]

​@@cherriberri8373what claims specifically is it you don't find trustworthy? Everything Derek presented here is either historical facts where you can look up the sources on every single person, or pure physics. The few times Derek has made bold claims without all the facts laid out, there has been an outcries from physicists in the comments. The fact that the comments are full of praise is because all the physicists watching recognize all the facts and are blown away by the genius way of presenting it. I dare you to point out a single factual error in this video.

[@garnettraypaul]

This was like watching the Ozymandias epsiode from BB, I felt my soul lifting as the video went. You give respect to every little effort you put into your phd Derrick, you truly have a gem occupation. The story of modern science and this perspective of seeing giant's interactions is just wonderful. I thank you for your endevour.

[@erthane]

god these are my favourite types of veritasium videos (e.g the video about the invention of imaginary numbers and the video talking about black holes) where they explain maths/physics but also fuse lore and story into it, so immersive and entertaining, keep it up! :-)

[@walaraubo]

Sometimes I come back and rewatch those. I’ve probably seens the Gödel/Hilbert video 10 times

[@jd2757]

Reminds me of one particularly interesting physics lecture in which my professor started with Heisenberg's Uncertainty Principles, which were reasonably easy to imagine, and performed the derivation to produce E=MC^2. The professor's intention, revealed at the last moment, made me wish I could see it all again. In light of my rather low-grade mathematical talents, I remain immensely grateful for your catalog of scientific delights... available to me on repeat... and to many others as an inspiration to remain ever hungry and thirsty for such knowledge. Your channel is a blessing and a gift. 🙏

[@mismis3153]

Do you still have that derivation ?

[@degenskonto6408]

I can barely count to 20 with my shoes on, but Veritasium videos about complex math and physics are always a treat.

[@TzarHiroki10]

This is everything I learned in my 4 years of college calculus class (and never understood). Well explained!

[@bituniverse8677]

I can feel the pieces falling into place too

[@cherriberri8373]

Condensed into 30 minutes. Yeah, I'm sure someone without background knowledge understood the topic, there are plenty of comments from people like you. But there are even more from people who simply just memorized an extremely short summary that leaves out so much that should and would be covered in an actual class.

[@anapalone]

<a href="#" class="seekto" data-time="1538">25:38</a> This is why I love math. When it was revealed that under all of that derivation and derivation results in an equation that we're all too familiar with, I just gasped.

[@peter11612]

It wasnt hard to spot earlier in the video 11:35

[@justno984]

how tf did you not know this?

[@Lq32332]

@@justno984how tf are you this condescending? 🤡

[@roelsvideosandstuffs1513]

Because every formula or equation you know is just the simplification of its integral and derivative. Or in the quote of a famous Mathematician "Simplicity is hidden beneath the mask of Calculus"

[@How19.]

who needs enemies when you've got friends like maupertuis's friends

[@verygood6625]

<a href="#" class="seekto" data-time="1628">27:08</a> --- Beautifully put, we can solve any mechanics problem ---- "with forces and vectors" or "Energies or scalars"..... Most modern engineers just focus on Newtonian Mechanics of forces and Vector (which is easy to comprehend) but we can get the real deeper understnadaning and visualization using Lagrangian Mechanics way of interretation. I have seen Mech & Aero under grads passing out without hearing the Lagrangain Mechanics and the equation at <a href="#" class="seekto" data-time="1676">27:56</a>.

[@johnchessant3012]

<a href="#" class="seekto" data-time="697">11:37</a> "to see the principle in action" lol

[@benjaminhill6171]

Nice catch. 😂

[@Nitish-Rathod]

😂😂😂

[@emanueleluzio484]

This was by far the best explanation of principle of least action i ever seen. Please, consider a I video on the maximum likelihood principle too!

[@mrawesome7811]

<a href="#" class="seekto" data-time="1625">27:05</a> damn I got goosebumps, it's like watching an inspiring movie with a happy ending. That's why I love physics❤

[@drevoksi]

The videos are getting more and more epic, I love to hear more about the history of mathematics and sciences. And it all blends together with the modern so well! It's incredible to learn, thank you so much

[@adityachakilam9575]

<a href="#" class="seekto" data-time="1620">27:00</a> literally gave me goosebumps

[@lazzatv]

Some arguments and misconceptions I found useful when thinking about this topic are: 1) The action is stationary rather than minimum as explained at <a href="#" class="seekto" data-time="1785">29:45</a> 2) F=-V' is a convention if one use F=V' then the lagrangian would be L=T+V instead and will stay the quantity that gives the action to "minimize" and the energy would be E=T-V and still be a quantity to conserve due to Noether's theorem. Basically the potential energy can be seen as a filling bucket rather than a leaking bucket to get a more intuitive view on the lagrangian as a physical quantity. 3) Newtonian, Lagrangian and Hamiltonian mechanics are not always equivalent (see the video "Newtonian Lagrangian Hamiltonian mechanics are not equivalent" by Gabriele Carcassi). 4) One could also argue that the principle of "least" action is more fundamental principle than Newton's law F=ma and also define in the most general way the lagrangian as that function that when integrated over time gives the action. It is possible to derive the principle of least action from F=ma and F=ma from the principle of least action but either way some extra hypotheses are needed, so which approach is more fundamental is arguable. For example sometimes lagrangian can be different than T-V and still giving a valuable action to minimize to find a solution to a physical system, when integrated over time. An other example is when non conservative forces are considered or when there is a magnetic field interacting with a charged particle that gives an extra term -q*A in the conserved quantity due to space transitions symmetries called momentum which would differ from the usual p=m*v. Also the presence of non-holonomic constraints on the system doesn't guarantee a general mathematical derivation of one approach from the other. 5) In quantum mechanics the principle of least action is useful but it works on "average" rather than always, it seems it will be one of the arguments in the next video.

[@cherriberri8373]

There will always be missing info and myths perpetuated in these veritasium videos. You can't boil down topics that takes whole classes to learn into a mere half hour and not be horribly inaccurate.