The Normal Distribution

I know of scarcely anything so apt to impress the imagination as the wonderful form of cosmic order expressed by the "Law of Frequency of Error".
The Law would have been personified by the Greeks and deified, if they had known of it. It reigns with serenity and in complete self-effacement amidst the wildest confusion. The huger the mob and the greater the apparent anarchy, the more perfect is its sway. It is the supreme law of Unreasoned.
Whenever a large sample of chaotic elements are taken in hand and marshaled in the order of their magnitude, and unsuspected and most beautiful form of regularity proves to have been latent all along.
The tops of the marshaled row form a flowing curve of invariable proportions; and each element, as it is sorted into place, finds, as it were, a preordained niche accurately adapted to fit it.
If the measurement at any two specified Grades in the row are known, those that will be found at every other Grade, except towards the extreme ends, can be predicted in the way already explained and with much precision.


Sir Francis Galton on Lapin, Statistics Meaning and Method