The Greeks were said to notice.........that if u filled an urn with water...........and tap on its side........that it would produce musical notes..............but only at certain intervals...........half full..........one third full, etc...........but is it the half filled with water..........or the space not filled with water responsible for creating the resonance.........................??

Put another way..........is the glass half full or half empty?  It is both of course.............

Harmonic Proportion and Form in Nature, Art and Architecture

https://books.google.com/books?isbn=0486428737

Samuel Colman, ‎Clarence Arthur Coan - 2003 - ‎Science

The great museums of the world are filled with vases of the Greek period, a large ... will outline this amphora or cinerary urn, disclosing the harmonic whole.

Nature's harmonic unity: a treatise on its relation to proportional form

https://books.google.com/books?id=jHZTAAAAMAAJ

Samuel Colman, ‎Clarence Arthur Coan - 1912 - ‎Architecture

The great museums of the world are filled with vases of the Greek period, a large ... will outline this amphora or cinerary urn, disclosing the harmonic whole.