It's not at all preposterous. Paul McCartney can't read music, he couldnt atleast when he started out and probably still can't. He doesnt need too. Like Macca and Jeff Lynne and many others, it's purely natural talent they have. As proved by Lynne and McCartney and many others, you don't have to have the ability to read music to be talented musician. I think Louis Clark has a lot to be thanked for within ELO, as together with Jeff Lynne, he was largely responsible for producing the strings for ELO.