"All that I have done since," he wrote when he was in his late seventies, "was there to begin with, so true it is that we can only develop what is born in the mind.
בשנות השבעים לחייו כתב: "כל אשר עשיתי היה שם מלכתחילה, זה כל כך נכון, אנו יכולים לפתח רק מה שנולד במוחנו.