“Mental life consists, according to the textbooks, of thought and feeling, according to the poets, of addressing an inner voice (or voices), and according to the dramatists, of internal monologues. In my experience however it consists mainly of intermittent silences, and humming. Humming accompanies habitual and semi-automatic activities, as well as stoppages. Humming accompanies a sort of incomplete concentration on oneself. Humming is characteristic of psychological states in which we are not exactly miserable, and states in which we are not exactly ecstatic. Which amounts I think to more or less always.”
―
Miroslav Holub,
The Jingle Bell Principle