“Some people carry their hearts in their heads; very many carry their heads in their hearts. The difficulty is to keep them apart, and yet both actively working together.”

Source: A Caress of Twilight

Heard in the D. A. Pennebaker documentary Dont Look Back (1967)

Source: Light on Life: The Yoga Journey to Wholeness, Inner Peace, and Ultimate Freedom, p. 29

The Tuft of Flowers http://www.sparknotes.com/poetry/frost/section2.rhtml
General sources

15 July 1944; Variant translations:
It's really a wonder that I haven't dropped all my ideals, because they seem so absurd and impossible to carry out. Yet I keep them, because in spite of everything I still believe that people are really good at heart.
I keep my ideals, because in spite of everything I still believe that people are really good at heart.
I simply can't build my hopes on a foundation of confusion, misery, and death...and yet...I think...this cruelty will end, and that peace and tranquility will return again.
Source: The Diary of a Young Girl (1942 - 1944)
Context: It's difficult in times like these: ideals, dreams and cherished hopes rise within us, only to be crushed by grim reality. It's a wonder I haven't abandoned all my ideals, they seem so absurd and impractical. Yet I cling to them because I still believe, in spite of everything, that people are truly good at heart. It's utterly impossible for me to build my life on a foundation of chaos, suffering and death. I see the world being slowly transformed into a wilderness, I hear the approaching thunder that, one day, will destroy us too, I feel the suffering of millions. And yet, when I look up at the sky, I somehow feel that everything will change for the better, that this cruelty too shall end, that peace and tranquility will return once more. In the meantime, I must hold on to my ideals. Perhaps the day will come when I'll be able to realize them!

The Two Paths, Lecture II: The Unity of Art, section 54 (1859).

Cassandra (1860)
Context: To have no food for our heads no food for our hearts, no food for our activity, is that nothing? If we have no food for the body, how do we cry out, how all the world hears of it, how all the newspapers talk of it, with a paragraph headed in great capital letters, DEATH FROM STARVATION! But suppose one were to put a paragraph in the Times, Death of Thought from Starvation, or Death of Moral Activity from Starvation, how people would stare, how they would laugh and wonder! One would think we had no heads nor hearts, by the total indifference of the public towards them. Our bodies are the only things of any consequence.

(A.J. Broomhall. Hudson Taylor and China’s Open Century, Book Five: Refiner’s Fire. London: Hodder and Stoughton and Overseas Missionary Fellowship, 1985, 350).

Endgame (1957)