The title borrows a famous line about the child being father to the man, and the poem plays with that idea by looking back at what a person once valued and what he values now. The early images are neat and hopeful: a sheet of paper folded into a boat, books standing like respectable citizens. Against them sits a sour note about money, "dead as the house" the speaker plans to live in, and about making bricks, which he calls "poor music." Work and ownership sound dull, even lifeless.
Then comes the turning point: to a boy, things seem bigger than they do to a man. The speaker doesn't sound bitter about this loss of wonder. Instead, the last lines settle on a small, humble pleasure, following a dog. The mood is quiet, wry and gently content. Having let go of grand expectations, the speaker finds good fortune in simply going where curiosity leads, much as a child might.