Quote Originally Posted by OngBonga View Post
He is at pains to point out that we simply do not know what happens at sub-Planck scales. However, it's not a question of measurement accuracy, it's a fundamental limit at which our models stop working. Our 4-dimensional model of the universe doesn't work at sub-Planck scales. That means length as we understand has absolutely no meaning.
Quote Originally Posted by MMM
That doesn't mean anything at all about the physics below those scales. It's just a statement about human ignorance or the limitations of models.
Quote Originally Posted by OngBonga View Post
It's not a math trick, no more than c or g are math tricks. It's a fundamental constant of nature.

I need to think this one through!
c and G are not math tricks. They're constants you have to go out and measure. There's no predictive model of what those values *should* be, there's only the busywork of actually doing the science and measuring them.

Google the Buckingham Pi method.
Google other "Planck" units. Like Planck energy, etc. All found by the same method as the Planck Length, but whether or not they tell us anything about the universe is not guaranteed.