petev3.1 wrote:From a practical perspective it seems to me that if one can play scales starting from anywhere then one only needs to know where to start. Learning the modes seems a great way of learning to play scales starting from anywhere, but I just can't seem to get a handle on why the two tasks are different.
Far from a theorist here, but from what I get the action itself (i.e. the "starting from a different note of the major scale") is the same. The only difference is that you talk about modes only in relation to a tonic note - the simplest example of which is a bass drone (but can be anything that constantly reinforces the tonic base of the piece, like a pad for example or just a progression of chords always containing the tonic note).
So "mode" does not reference just the action, but the action plus the context... hence, the "start from anywhere" is only half the story; the other half is to have the fixed tonic reference going on while you're starting from anywhere.