...someone tried to explain it to me as such: improvisation built on chords would be playing those notes in the key you're playing in - but improvisation built on scales would be like playing the notes of another key...for example if the melody is in the key of C, and your improvisational solo is in the key of F#. Yes...No...Maybe???

greg stephens' post infers an atonal, twelve-note approach...not playing in any key at all?