“But if we habitually use inaccurate intervals (tempered scales) on the grounds that our ear does not clearly perceive the difference, the effect that those sounds will produce on our organism can well be the opposite of that which our complacent ears persist in accepting.  It is with our mind alone that we accept this inaccurate music, which leaves us tired and tense through an unconscious effort of adaption, instead of agreeably transformed by the beneficial influence of the harmony.  This is why disregarding small differences in intervals has very grave con-sequences with regard to the deeper effect of music, consequences that can only be neglected when the real purpose of art is totally misunderstood.
Unfortunately the materialistic and highly utilitarian tendencies of our times rarely allow people to bother about anything that is not immediately tangible.”

(Danielou, Music and the Power of Sound - Rochester 1943)