Scientific knowledge can help us formulate and understand basic principles more thoroughly, to define and use terminology more concretely and factually, and to determine more fully the potentialities and limitations of our craft. But singing and the teaching of singing must always be recognized as a creative process, while science as it applies to the vocal function is pure analysis; analysis in terms of theoretical possibilities on the one hand, and analysis of the harmonic content of tones after they have been produced on the the other.
Reid, Cornelius L. The free voice: a guide to natural singing. Joseph Patelson Music House, 1978.