A 9-line summary of textbook physics
&gt; <i>Lines 1, 2 and 3, together, uniquely determine special and general relativity, cosmology, the Hilbert Lagrangian and Einstein&#x27;s field equations, as told here.</i><p>This is a huge exaggeration.<p>For example 1 says &quot;W=∫L&quot; but L is never defined. The definition of L hides a lot of details, in particular that each point of the universe is equivalent, so there is translation invariance that using the Noether&#x27;s theorem implies the conservation of momentum.<p>There are many definitions of L, for example if you are analyzing bead that locked to a circular wire, it&#x27;s usual to define L with a coordinate that follows the shape of the wire. There are also definitions of L in spherical coordinates, where each coordinate is different. Anyone with a Major in Physic has nightmares about the posibilites to define L.<p>For example in 2 &quot;v ≤ c&quot; can be true in a stupid universe where the force is bounded and there is enough friction everywhere. Imagine a universe that is full of &quot;water&quot; or &quot;aether&quot; or other magical thing with magical friction. And for some reason the force is bounded, for example like the post says in 3 &quot;F ≤ c4&#x2F;4G&quot;<p>Also, I can&#x27;t imagine how it is possible to rediscover all thermodynamics from &quot;S ≥ k&quot; in item 5.