Topic: Major and minor scales explained for complete idiots like me
When playing music I always want either to rage myself out or to relax or set emotions free or take music as poetry to meditate world and life. I do not want to do quantum mechanics at the same time. This is why I don't like the rocket science of scales. And this is why I want to offer you how I explain to me how major and minor scales work. This thread could be named "Why major and minor are the most popular scales" as well, because to my opinion these thoughts explain why they work best for the needs of western music.
First of all we need two preliminary and basic facts that are taught in science, but which everyone knows by heart as well:
1. A note / pitch to be emphasized is best approached by a semitone upwards movement. It says: here is the target! (There have been psychological experiments done about it. Jazz players know: if you hit a wrong note, just sell it as an approach tone to the next semitone upwards. In renaissance music this semitone upwards indicates the melody ending in the melodic formula of the main voice.)
2. The one basic movement in designing music (in all cultures and ages) is the fifth downwards - in melody the same as harmony. (This is already given by the pure math of the harmonics: the fifth is the next relative pitch after the octace) In most cases the level of the fifth first has to be reached, which explains the basic cadence: I-V-I which is expanded to I-IV-V-I. (For this subdominant IV see later.)
This is enough to explain the rest!
Given the center tone, the root note of any music activity, there can be only two basic movements which involve the root pitch: either it is reached by the fifth-downwards or the fifth-downwards starts with this pitch. Here is the subdominant IV! By this we have three pitches: root, it's upper fifth, it's "lower fifth" which we call it's fourth.
Now if you want to emphasize the targets of these two movements you may stretch them and put a semitone-below before the target note.
Now you have not only the root pitch and it's fourth and fifth, but in addition two further notes in semitone distance. They are below the root and the fourth and help to make the happenings logical and satisfiying.
What about the two pitches left? Why are they in whole-tone-distance to their neighbours? They can be explained by the need to make major and minor triads, which would imply that major and minor triads would be primary (they can be explained by the maths of the harmonics which is theoretical physics) and the resulting scale would be secondary.
I personally prefer another and more philosophical explanation: Emphasis means non-symmetry, means creating a difference. You can not emphasize all things by painting them red. You only paint the most important signs red. So now that we have already emphasized two targets, which are the root and the fourth, by semitones underneath them, then let's not destroy this effect by emphasizing others. This means: take unobstrusive distances, which are the whole-tones. This is in effect the major scale.
The minor scale is related, but it's fifth-downwards-targets lack the semitones. To emphasize at least the root note people shift the seventh one semitone. If you extract all the pitches you get the harmonic minor scale. Now there is s three-semitone-gap which sounds quite arabic or indian and brings difficulties for the triads. To smoothen this people shift the sixth as well and they get the melodic-minor scale.
I want to stress that until here it has always basic requirements from melody making and very archetypal harmony making that formed the design of the scale. There has been scale theory ever since the age of bacteria, but what I want to say is that there is a logic within the scales which is psychological and practical and not mathematical and which makes scales more comprehensible. Once I met an extraordinary jazz bass who told me he didn' think in scales at all, but in related pitches and their approaches.
Thanks and please comment. I better leave out the joke about the term "string-theory" ...