Fair enough, although even that terse lecture hand-waved (by leaving it to a reference) about ergodic systems. I think the deeper point is along the lines of W

Fair enough, although even that terse lecture hand-waved (by leaving it to a reference) about ergodic systems. I think the deeper point is along the lines of Wigner's classic "The Unreasonable Effectiveness of Mathematics in the Natural Sciences" http://en.wikipedia.org/wiki/The_Unreasonable_Effectiveness_of_Mathematics_in_the_Natural_Sciences http://en.wikipedia.org/wiki/The_Unreasonable_Effectiveness_... It happens to be the case that elementary dimensional analysis is sufficient in the case in hand -- and it often is.