Music in earlier times primarily meant singing, so that a person could produce the sounds from within the body; there was no reliance on artificial outside assistance as provided by an instrument. So, the earliest written symbols for music were essentially related to what the human voice could do, and by definition, what the inner ear could imagine. It seems likely then, that an earlier ability to manipulate or write down symbols for harmony were originally connected with what the inner ear, assisted by the, voice itself, could conceive in the imagination. Since the art and science' of harmony must inevitably have been of fairly slow evolution, it was probably not so difficult for musicians to get used to such a written symbolism for sounds: the imagination of which in the inner ear, could readily be verified by singing them. At one time it used to be a maxim that composers should be able to compose "in the head" without the aid of an instrument. It is almost certain that the great composers of classical times were able to do this unquestionably. The language of written notation was formulated and stabilised, a musician's instincts so firmly and securely based, that even the most humble could compose and be assured of conceiving in his or her own head the "right" harmony notes to go with the melody.
