Is Adams just effacing himself and being humble? If not, please explain this apparent contradiction?
Adès and Adams: Big Composers With Simultaneous Big Premieres - The New York Times
“I can’t play the piano,” Mr. Adams, 72, confessed in an interview. “I have never even taken a piano lesson.”
That hasn’t stopped him from writing some of the most spellbinding contemporary music for the instrument, like “Phrygian Gates” or the joyous and sweeping “Grand Pianola Music”; or the duet “Hallelujah Junction,” which was inspired by the name of a truck stop and was a case, he has often said, of a title looking for a piece.
Schoenberg wrote one Piano Concerto, but also "lacked the performing skills that enabled such composers as Bela Bartok, Paul Hindemith, Ernst Krenek, Igor Stravinsky, and Ernst Toch—as concert promoters". 1 "Mitsuko Uchida (2007), describing the work as very difficult for the pianist, points out that Schoenberg did not play the piano very well"2.
An analogy can elucidate my bewilderment. If you can't even write in a certain language at the A1 Level, then how can you compose any literary or scholarly writing in that language? Rule out translators who are analogous to orchestrators.
My question can be distinguished from As a composer, should I be composing music for an instrument I don't play?, because that latter asks whether an amateur OUGHT to compose, but here the composers have already composed!
1Dorothy Lamb Crawford, "Arnold Schoenberg in Los Angeles", The Musical Quarterly
Vol. 86, No. 1 (Spring, 2002), p. 10.
2https://en.wikipedia.org/wiki/Piano_Concerto_(Schoenberg)#Sources