Big rehearsal for The Planets today. “Mercury”: lightning fast, ripping atonal scales, constant meter changes from 3/4 to 15/16 to 11/16, different tempos at the same time like 8-against-9 – went great, sounded perfectly secure. “Saturn”: slow, plodding pulse, rhythms in quarter- and 8th-notes – had a hell of a time pulling it together. I remember this from my early days as a competent pianist: difficult music is a lot easier to play than easy music. Scriabin’s fiery D#-minor Etude, with its relentless triplets and huge leaps, used to just fall under my fingers, while the Lento final movement of the Copland Sonata was a minefield of wrong notes. Why is that? Is it just because we practice hard music 20 times as much as easy music, or is it psychological, or what? Too much time to think in-between the notes?