I have experienced, he says of himself in _Sordello_, something of the spite of fate.
Then, having done this, he leaves Sordello at the end of the third book, and turns, beset with a thousand questions, to himself and his art in a personal digression.

Reclining on a ruined palace-step at Venice, he thinks of Eglamor who made a flawless song, the type of those who reach their own perfection here; and then of Sordello who made a song which stirred the world far more than Eglamor's, which yet was not flawless, not perfect; but because of its imperfection looked forward uncontented to a higher song.

Shall he, Browning the poet, choose Eglamor or Sordello; even though Sordello perish without any achievement?
And he chooses to sail for ever towards the infinite, chooses the imperfection which looks forward.

A sailor who loves voyaging may say, when weather-bound, "Here rest, unlade the ship, sleep on this grassy bank." 'Tis but a moment on his path; let the wind change, and he is away again, whether triumph or shipwreck await him, for ever The tempter of the everlasting steppe.
That much is then settled for life and for poetry.

And in that choice of endless aspiration Browning confirms all that he thought, with regard to half of his theory of life, in _Paracelsus_.