unrefuted song

I am happy, and I think full of an energy, of an energy I had despaired of. It seems to me that I have found what I wanted. When I try to put all into a phrase I say: 'Man can embody truth but he cannot know it'. I must embody it in the completion of my life. The abstract is not life and everywhere draws out its contradictions. You can refute Hegel but not the Saint or the Song of Sixpence.

—W. B. Yeats, in letter to Lady Elizabeth Pelham three weeks before his death.