Frost sets youth against age in two compact, parallel stanzas. As a young man, the speaker learned from the old: he traded fire for form, gave up warmth and spontaneity for discipline, and felt the pain of being shaped like molten metal poured into a mould. That schooling meant learning the past. Now, at fifty, the direction has reversed. His teachers are the young, and the old rigidity that once meant order will no longer work; what can’t be moulded must be cracked and sprung. The lessons hurt in a different way, like pulling a wound closed. The speaker sounds wry and a little rueful. The mood is clear-eyed rather than nostalgic — learning never becomes easy, it just changes which side of the gap you stand on.
What Fifty Said — Summary
When I was young my teachers were the old. I gave up fire for form till I was cold. I suffered like a metal being cast. I went to school to age to learn the past.
Now I am old my teachers are the young. What can’t be moulded must be cracked and sprung. I strain at lessons fit to start a suture. I go to school to youth to learn the future.