Sorry I didn't mean 'nonsensical' as an insult! ;) I just meant...

Sorry I didn't mean 'nonsensical' as an insult!

I just meant it literally - the paragraph makes non-sense, because Newton's laws don't require discrete units of time (nor does relativity, it's a classical theory). In fact even quantum physics doesn't really use quantised time units. Both space and time in quantum physics are continuous variables, not quantised variables.

But due to quantisation of other variables we do end up with the smallest time and length scales that have meaning - the Planck Time and Planck Length.

Newton's laws are a special case of relativity where time is approximated as absolute. This approximation only holds when the velocities involved are much less than the speed of light.

Newton's laws are also a special case of quantum physics where masses and lengths are much bigger than quantum effects, but time in quantum is much more similar to time in Newtonian physics.

The problem is trying to reconcile time in relativity to time in quantum physics. They are fundamentally incompatible theories on many different levels.