Wednesday, July 15, 2020

so, we're through the second lecture series, now. i'm going to watch a talk on public policy around climate change, and then the third series is on "quantum entanglements", and we might get our talk about bell either after or during it. given what i've seen from susskind so far, i'm expecting a mathematically truncated but theoretically thorough formulation of entanglement, which should once again give me some space to actually learn something.

this is presented as an introduction to classical mechanics, so i assumed the pre-requisite would be very introductory calculus and he'd just work out some basic newtonian equations for engineers. i only decided to watch it as review, really.

in fact, this is an exceedingly abstract course that would more or less need to be presented at the graduate level as almost a kind of philosophy course and, if presented with a more thorough mathematical development, would have third to fourth year mathematical prerequisites. he hints at a lot of pretty esoteric math that i, myself, barely touched upon, but he doesn't actually do any of it, he presents these kind of intuitive, ad hoc approaches that reduce some pretty hefty math to a kind of half-hacked out differential calculus. i can honestly argue that if i had tried to present some of these proofs in a paper in a math program, i'd have received a failing grade; however, very little of the audience for this specific lecture series could have followed these arguments if properly formalized, so he kind of had little choice but to chop his way through it, allowing an audience that is interested in mechanics at this level to follow a series of arguments that they really shouldn't be able to follow. that said, much of the calculus in this course is at a second year level, and i don't really recall working with any kind of abstract algebra until the second part of second year. so, even with the intuitive sloshes through topological spaces and measure theory, amongst other things, you'd still need to be an upper level undergrad to even start to follow this, and i'd imagine few people would have the incentive to relearn classical mechanics, except as a weird and sort of meta elective.

i was hoping that he'd develop some more known physics from these systems, but he didn't have time, and so instead focused strictly on developing the algorithm. he claims that the algorithm will then allow you to derive the equations of motion of any system, and he did manage to convince me of it, but he didn't actually do much of it, like i'd hoped.

i remember taking courses like this near the end of my time studying math, and they have their place, but don't be fooled - this isn't for beginners. what this is is a demonstration of how very advanced physicists do very basic physics, and it's consequently only going to be of interest to the general populace as a point of curiosity, rather than a serious course.

stated differently, if you can follow the math, then you already know all of the physics and it's only interesting as a philosophy course. but, if you can't follow the math, even with it simplified, you're not learning much about physics by following along - you're better off checking out the pre-reqs.