He argues:

There must be an underlying deterministic system. - We don’t know what it is yet. - Quantum mechanics is incomplete, not wrong — it hides deeper rules. - His belief is based on logic, not current experimental proof.

In short, he says we don’t know what it is, but it’s something out there.

I think our numerical system is a bit like Fahrenheit.

Fahrenheit draws a line between three points and assumes a "law in nature". This was false (short answer).

The fact that there are things like PI for a circle means our numerical system has been invented before we had any knowledge about quantum quantities for lack of a better word (like autonomous autos X).

Math is wrong. But it's gotten this "holy" status of almost defining intelligence, like Latin is to English.

It's clearly wrong (to me at least) but it's such a big part of "smart" people's egos.

Unfortunately the correct simulation hypothesis not only can explain how, but also why. There are many wrong formulations of the sim hypothesis, but when done right it can explain almost everything. For example, Constructor Theory is in fact an instance of the simulation hypothesis done quite right, as it avoids the computational problem by stating that the universe is not computed but is itself a “constructor”, which is a computer that can manipulate matter (simplified). Although I agree that Quantum Physics is incomplete, I also don’t think there has to be an underlaying classical picture. But, yeah, we have the wrong point of view on it. The simulation hypothesis (if, again, done right) offers a far better insight on what QP is and why it works like it does. It can explain easily what is Entanglement and why it works like it does. It also offers a pretty good insight on what General Relativity actually describes, and why it works like that. Also offers a very good explanation of the “God plays with dice” problem, and the BH information paradox. That’s all IMHO, of course.

Why does a cat being both alive and dead sound like nonsense? It seems to me to be the most accurate description of nature. The "cat" is some kind of soup of cells and other more primitive life forms engaged in a pitched battle for resources that results in the experience we categorize as "cat". To us at scale, we create the ontological notion 'cat" but reality does seem not care about our ontology. That is all you need to accept in order for the quantum mechanical formalism to lose its mysteriousness.

I have a gold medal in theoretical physics and I find quantum mechanics presents no difficulty or mysticism. There is however significant lament that the reductionist paradigm has failed to produce a deterministic universe from the decidedly probabilistic one we inhabit.