His intellectualism arose (as it does in most) from a fear of boredom — in particular, I suspect, from an awful anxiety that music itself would fail to satisfy his personal need for meaning. While rehearsing for his concert debut at 23 years old, he completed a PhD in French literature at Princeton, adding further credits in mathematics and philosophy. Making his first records, he dispensed with hack-written sleeve notes and composed his own. A publisher, impressed, commissioned The Classical Style, an award-laden book which not only defined lucid distinctions between Haydn, Mozart, Beethoven and the rest in truly original capsules but served for 40 years as the final arbiter of style — the top item on every music student's booklist and a cop-out for academics who never needed to rethink classical form once Charles had nailed it.

He was, by this exalted measure, the ultimate fusion of keyboard and cerebellum, of profundity and playfulness, of performance and reflection — all of these, along with such other expert interests as French cuisine, 19th-century art history and the ribald tradition in English theatre. 

Brilliant as violinists can be, charming as most cellists are, none can play the public intellectual as pianists do. From the high brows of Liszt and Busoni, to the iconoclasms of Scriabin and Wanda Landowska, from the religious devotions of Maria Yudina and Albert Schweitzer to the logical perversities of Artur Schnabel and Glenn Gould, pianists assert the right to think aloud, independently and outside the box.

String players have to fiddle too much with bits of hair and gut and rosin to find the leisure for intellectualism. They have to make their own notes, where pianists have everything laid out for them in black and white. Violinists turn to other musicians for mental stimulation. Yehudi Menuhin, a man of the greatest imaginable curiosity and most catholic interests, told me that he relied on his accompanist for enlightenment on lengthy prewar tours. If the pianist read thrillers, he got replaced. A pianist was meant to raise his partner's IQ.