We musicians like to dress up what's going on in our special nomenclature, often made opaque by being translated from one language to another or not. It took me a few weeks as a student to decide that in Schenkerian Analysis, beloved of the Americans, N for Neighbour note denotes what is in British English an auxilliary note and not sometimes or in certain circumstances, but always. In my defence, I had just switched from first year Maths to second year Music and in Maths new word = new idea, or we have to write 'is identically equal to.'
So, strange words.
Musing on the sound world of Colours of Day the other day and it's banal use of a tetrachord - four notes; or is it the words, (dawn into the mind - answers on a postcard...)or is it that the tune is sort of symmetrical, but not quite, or all sorts of other grating things that just prevent it working. It's like an OK Composition for GCSE where the pupil has listened to you, but it just isn't very good and it's hard to say something to make it better. It's just boring.
How different is Ubi caritas, which at least to start with also only uses the first four notes of what we would now call a major scale. That melody is totally logical, balanced, comes to rest when you expect it to and on the note you expect, is at one with its text and is very very simple. Great melodies have an inevitability about them. We know it's all going to end well.
Maybe that's why the 20th and 21stC's have seen the almost total demise of fantastic melody writing. (Brahms, Dvorak, Tchaikovsky, where are you?) The linear thread that comes to a happy conclusion, is just not part of our unhappy times.
Plainchant is the ultimate monophonic linear thread. No other musical parameters to hide behind. Can't do a Schoenbergian Klangfarbenmelodie and keep changing the instrument and register to dress up your desolate atonality.