This doesn't have to be true. Goethe managed to stay fresh his entire life - even the poetry he wrote in his late years was seen as expanding the art form; if t

This doesn't have to be true. Goethe managed to stay fresh his entire life - even the poetry he wrote in his late years was seen as expanding the art form; if the mind ossifies over the years it's probably because one has grown complacent and stopped expanding, rejuvenating, overcoming oneself. A categorical statement about age is just an excuse, IMHO.