Which is exactly the case. And it can be arrived at not only by scientific investigation, but also self-inquiry, meditation, psychedelics, lucid dreaming, etc.

https://senderspike.medium.com/what-color-is-red-2c7cf7cb40db

As for impossibility to measure thought, I wouldn't be so hasty to jump to conclusions as you do:

https://senderspike.medium.com/mind-brain-and-consciousness-9127f14dea4

Furthermore, you seem to conflate mind with consciousness. It's a common error committed by both materialist and idealist camps respectively. Nevertheless, and quite surprisingly, even the ancient ontological frameworks basically agree with modern materialism (to a point):

https://senderspike.medium.com/absolute-equivalence-b4584dc2e290

https://senderspike.medium.com/tree-of-life-2d7b5f28eda2

All in all, World, indeed, can be boiled down to, and described by, "the equivalent of mathematical equations" only the true nature of reality cannot be captured in the same way. And that's a substantial difference.

Well, know yourself and you will know what I'm talking about.