"Interval" is most commonly defined as "the space [or distance] between two pitches, sounded either simultaneously or one after another". What is wrong with that definition? It seems right, doesn't it?
Well, it's not the exact definition. It's incomplete. Let me tell you why. If we look at a map and define a "country" as the "space between the borders of the country" but DON'T include the borders (or edges and outline of the country on the map) as PART of the country, we are missing an important component of the real thing. If we were to leave out the shoreline all along America's coast and just define it as the inner states, how are we to grasp the real shape of the country? That's because the space of any country includes more than the middle section, it includes the borders or outline. What does this analogy have to do with the definition of "interval"?
Everything! An interval isn't just the space BETWEEN the notes, it's the actual two notes themselves, what they sound like (either sounded at the same time or one after another)! Each type of interval, from the ones close together to the ones which stretch over a wide space, each type of interval has its own CHARACTER and quality, its own emotional content, its own SOUND. If you were close, I'd show you.
