http://www.ted.com/talks/joshua_prager_in_search_for_the_man_who_broke_my_neck.html

VIII
Labour is blossoming or dancing where
The body is not bruised to pleasure soul.
Nor beauty born out of its own despair,
Nor blear-eyed wisdom out of midnight oil.
O chestnut-tree, great-rooted blossomer,
Are you the leaf, the blossom or the bole?
O body swayed to music, O brightening glance,
How can we know the dancer from the dance?

• Yeats looks for a solution to the pain of unrequited passion. In this poems original ending, Yeats conjures the nostalgia of the spring of youth and reciprocated sexuality.
• Yeats looks towards nature for inspiration, admiring the grand chestnut tree, giving forth blossoms even after old age with a continual spring of vital energy:
• However, Yeats acknowledges that mankind in old age is not looked upon with such veneration as is the old, stately tree.
• In asking his final question as to the use of a long life, he looks to the dancer – a dancer who creates his or her own choreography to the constraints of the pace of musical accompaniment.
• To Yeats, life is a series of fluid and self-invented steps, not governed by time but rather invented against time.

“truly to enjoy bodily warmth, some small part of you must be cold, for there is no quality in this world that is not what it is merely by contrast. Nothing exists in itself. If you flatter yourself that you are all over comfortable, and have been so a long time, then you cannot be said to be comfortable any more.”