I'm sure you can, but what about over an hour of complex music containing no "grooves" or repeated patterns? Classical scores are beasts. For the record I play jazz and memorize everything and play by ear. I also play in a brass band and although I end up memorizing much of the music to fully memorize it would take more time and effort than I have available. Top soloists absolutely memorize everything though. Lang Lang doesn't use sheet music when he performs.

Performed by the person who composed the part, most likely.