Topic
Goethe's call to begin — whatever you can do or dream you can, begin it — is the most action-oriented statement in a collection that tends toward reflection. Shaw's famous dream-versus-reality reversal (you say Why, I dream Why not) is the rhetorical companion: imagination is not escapism but a more honest engagement with possibility. Thoreau's instruction to advance confidently in the direction of your dreams gives it epistemological weight: imagination is not fantasy but navigation. Edison's good imagination and pile of junk is the most honest description of invention available — the materials are always already there; imagination is what reorganizes them. Twain on the crank with the new idea restores the social reality: imagination produces people who look wrong until they're right. Thoreau's aircastle instruction returns — build them in the air, where they belong, then put foundations under them. Marriage appears twice in imagination's company, once as Wilde's triumph of imagination over intelligence, once as hope over experience. The collection's argument is that imagination is the faculty capable of asking what should be, not only what is.
Our truest life is when we are in dreams awake
My imagination is a monastery and I am its monk
I am certain of nothing but the holiness of the heart's affections, and the truth of imagination.