It is almost certain that these similarities came about in a deeper way than simple self-quotation. They give us an insight into the composer's creative process, of how particular images and situations prompted musical shapes, or tonal analogues, which rose from his unconscious in response to those situations. It is in this way, surely, that a highly personal musical language such as Schubert's came into being. Both poems (in the same metre, incidentally) deal with stories which are inspired by the sight of water. Thus the 'Bächlein helle' of Die Forelle and the 'klarer Quellen Rand' of Die Erscheinung (both appear in the poems' first line) are related despite the fact that this is, strictly speaking, not a water song: the apparition appears from the grove and is no water-nymph or Lorelei (as in Goethe's Der Fischer). There is also a tinge of melancholy in both poems about the sad ways of the world; in both songs lessons are learned from observation of things that the narrator would have wished otherwise in a more perfect world. The crucial thing from the composer's point of view is the sound of the lapping water which has put the narrator into the dreamlike state necessary to welcome such a vision. As we have seen, it was also the sound of water running metaphorically in the composer's head which gave rise to the melody. Indeed water runs through much of the song like a gentle accompanying leitmotif in pianistic double thirds. The postlude is particularly successful in this regard: gentle cascades in thirds and sixths in three different registers of the piano (with a succession of Es in the left hand which drop an octave for each successive bar) murmur their impartial commentary on this beguiling dream.
from notes by Graham Johnson © 1994