Western music has, for the last 1000 years or so, been founded on a very simple principle - the octave and the standard music stave. This system has been used by everyone from Bach to Lady Gaga. It is at once clear in it's simplicity - it can be read and understood in an instant by any musician. Yet also profound in it's depth. It can convey a simple one line melody or the full glory of a Beethoven symphony for full orchestra and choir.
At it's heart, however, it remains simply an octave. From those single tones are developed chords and their inversions, different types of scale, harmonies, discords and melodies. They have the power to stir emotions, lift spirits or give us a nice tune to whistle.
Anyone who learns how to play music in the "traditional" sense begins with the octaves. Running up and down those 8 notes in their various keys and scales. Correct positioning to play the notes fluidly, correct technique for the particular instrument you are working with are the first steps. Then you start to learn something of the relationships between these tones, how thirds and fifths work, how chords are created.
Of course music is written to be performed, so at some point every musician will play in front of someone, even if it's just family. Now you begin to learn to cope with the pressures of actual performance as opposed to practice. Nerves, expression, ability, not to mention the fun and enjoyment performance brings.
This is within reach of anyone who takes up an instrument within 6 months or so. With good tuition and a little practice it should be easy to reach this level. But what lies beyond? Why do some stay at one point and others go much further? There are several factors of course, but for the sake of argument let's make it a level playing field and say all things - time, money, opportunity and desire -are equal. The variables then must be in the people themselves and how they view the playing of music.
We could say that music is a mathematical exercise. After all it was Pythagoras who "discovered" the laws of music. So if a person understood completely the mathematical relationships between all the notes in a piece of music, they would be an amazing composer, right? You could create a score based on tonal relationships and intervals that would be neat, tidy and rational
We could also say that music is an exercise in technique. The faster I can move my fingers, the better. The more notes I can cram in to a phrase, the better I am. People will be amazed at the speed and dexterity of my playing, the flashiness of my performance.
Then again, music is an exercise in theory. See how cleverly the chord in the first section is inverted in the second and a diminished fifth added, which relates to the the harmony of the string part in the fourth movement. The more elaborate and complex the piece the more people will appreciate my intellect and cleverness - I can discuss it endlessly on internet forums, I don't even have to play anything for people to appreciate my genius.
Perhaps music is all about learning things. If you go to a teacher who just gives you the eight basic notes and asks you to work with them, what use is that? Isn't it far better to have a teacher who has strict rules for everything and can take you step-by step through it all? That way I will never have to think for myself, everything is neatly laid out for me. My work will be exactly the same as my my teacher and can be replicated over and over again.
Music is a language. Through someone else's work or your own, music is a form of expressing a feeling, an emotion, a sharing of joy, pain, love, anger or just the desire to get up and dance. It touches something deep within us and connects us to something outside of ourselves. There are aspects of all those previous things I mentioned before in there of course. Understanding theory, technical ability and so on are all valuable - but not at the expense of the necessity of honest self expression.
This is what takes the student "one step beyond" playing simple scales and into the realm of understanding, performance and creativity. But only if the student is willing to take that step and has faith in the process. It's easy to look outside and blame others for not showing you things when in fact they are in plain sight. Of course if you want to keep someone as a student this is how you teach them - step-by-step, keep everything obvious and mechanical, drip feed "information".... But if you want someone to become a real musician, you encourage them to imitate... then innovate. A little guidance is necessary here and there but the information is all contained in those eight notes - you just have to open your eyes, ears and heart to see it.