>but rather than just the parts of physics that the author considers to be the most fundamental.
Fundamental is what "contains all of physics" means in this context (key word: contains). The rest would be emergent properties.
Fundamental is what "contains all of physics" means in this context (key word: contains). The rest would be emergent properties.
- action is extremized or at a saddle point, not necessarily minimized
- Action is not quantized in QM (and quantum-mechanical action is not quite the same as classical action). There's another very indirectly related notion of "action" which shows up in historical semiclassical approximations and which is quantized. The author has likely confused the two.
- SU(2) is not the gauge group of the weak interaction, because there is no such thing. A purely weak gauge theory with no EM is not possible, on account of having massive force carriers. The SU(2) and SU(1) in SU(3) x SU(2) x U(1) corresponds to weak isospin and weak hypercharge respectively, not weak charge and (EM) charge.
But even if all the errors were corrected there's a huge amount of missing context. (For instance, the actual content of the standard model Lagrangian - the fact that there are 19 free parameters is in no way sufficient to determine it) And even if you had all of that, a full reduction of macrophysics to microphysics is likely computationally intractable, even in principle.
A few equations being fundamental for big theories built upon them wouldn't be unheard of. Maxwell's equations for example cover several important fields of Physics. Newton's 3 laws cover classical mechanics.
Take something simple like "F=ma" which is in lots of textbooks. Nothing in those 9 lines seem to suggest anything that could be used to derive that.
I'm sure a domain expert, who already knows all this stuff, I'm sure they'd be useful as a memory aid to help them trot this stuff out, but do they "contain all present knowledge about nature, ..."? Not so much, if you need a ton of other knowledge to make use of them.