I’ll try to dig out Griffith for a better explanation but has to do with the fact that when you do a partial derivative you kinda lose information I guess?

(Idk, this is heady trying to make math into reality shit and I got a “c” in the class (for reasons partially related to other things) - also, there might be a way to do latex in markdown but I’m a bit too stoned to figure out, look up Schrödinger equation on wiki for maybe a helpful visual aid)

So go back how often we do implicit differential because it’s just an opportunity to look at how sexy the chain rule [edit: product rule, you get me though. math is easier sober] is. d(xy)/dx = xy’+x’y god fucking dammit that gorgeous

But okay. Think about position and velocity. Velocity is the derivative of position right (and also connected to energy - KE = 1/2mv^2 and E = mc^2 lol)

But since velocity is a derivative of position, it loses information. d(mx+b)/dx turns into m, no way to ever get b back with an initial value condition.

Then - omigod, when you take a partial - you have to ignore dependence. curlyd(xy+by)/curlydx turns into y and then things is really fucked if there was any dependence on y (ie, doing curlyd(xy+by)/curlydy would give you a different answer if you did that first order matters I guess)

There are some operators that are just exclusionary. Once you chose to look for one, you’ve discounted the chance of finding the other. Taking position versus taking energy/velocity. And then the fucky thing there is lots of shits mass is measured in eV/c^2

(I’m neglecting a proper discussion of momentum which is 100% where someone can come in and humiliate me. Please do so.)