All poetry is supposed to be instructive but in an unnoticeable manner; it is supposed to make us aware of what it would be valuable to instruct ourselves in; we must deduce the lesson on our own, just as with life.
An actor should take lessons from a painter and a sculptor.
Do not, I beg you, look for anything behind phenomena. They are themselves their own lesson.
Stones are mute teachers; they silence the observer, and the most valuable lesson we learn from them we cannot communicate.