Dear Noson,
I was first reluctant to read your essay, because I am not interested to learn how our mind imposes limits on physics. Or is it the other way round? I am interested to learn, how the world is. But I must agree with you, we can't.
I certainly also agree that our mind performs incredibly well in ordering the world. And also that the naive, object like reality we attribute to our sensations is a construction of our mind. Also Poincaré shows, that our mental reconstruction of the outside world distilles the invariant features of our mulitdimensional sensory input. The description of the sensory input as a process is also a mental reconstruction (by the way).
But I do not agree with the consequences you take. And here I want to start to promote the view I take in my essay.
The main critic is an inconsistency in the argumentation: in a way you seem make a point, that the underlying reality is not the way we picture it and on the other hand you seem still to assume the existence of some true reality, that is not knowable, but to which you compare the minds reconstruction as false, approximate or illusory.
Of course if there is no such thing to which our models can be compared, then the notion of truth becomes somehow vague.
Regarding the mental reconstruction, I have another view. Since we and our mind are part of the physical world, our mental constructs got it approximately right for the specific environment. "The ship swims." is a good an true proposition, if we live in a world, where there is water and gravity. The meaning of 'ship' lies not in how it is composed, but in his mesoscopic properties.
Regarding the classical physics, you are certainly right. They apply on systems that must be completely isolated from the rest of the universe. Ideally empty. But this separability is a necessary approximation to have well defined properties and objects and well defined laws. Then we are able to model the environment as disturbance. If these disturbances are to strong, such that the approximation does not work any more one might need look for other separable systems and objects. For new concpts. (More on this in my essay.)
This approximate applicability of concepts and laws might be all there is. This means that these concepts are neither illusory nor false.
I might have twisted your words a bit in order to make them fit my argument. Sorry for that. Last but not least you wrote an enjoyable, well written, thought provoking essay.
There is nothing one could do better.
Good luck in the contest.
Luca