I appreciate Sabine Hossenfelder's take on MUH[1]:
"...the justification that we have for calling some mathematical structures real is that they describe what we observe. This means we have no rationale for talking about the reality of mathematics that does not describe what we observe, therefore the Mathematical Universe Hypothesis isn't scientific."
"...this is a belief-based statement, not supported by evidence."
Sabine is either straw manning or didn't read the actual paper, because the whole point of Max's paper is that there's no substrate or quintessence beyond just the mathematical properties.
If her counter is that "No there isn't just mathematical properties", then what is there? What is a quark if not its mathematical properties?
"...the justification that we have for calling some mathematical structures real is that they describe what we observe. This means we have no rationale for talking about the reality of mathematics that does not describe what we observe, therefore the Mathematical Universe Hypothesis isn't scientific."
"...this is a belief-based statement, not supported by evidence."
[1] https://www.youtube.com/watch?v=CTpp0EChDbI