Belief in inspiration. - Artists have an interest in the existence of a belief in the sudden occurrence of ideas, in so-called inspirations; as though the idea of a work of art, a poem, the basic proposition of a philosophy flashed down from heaven like a ray of divine grace. In reality, the imagination of a good artist or thinker is productive continually, of old, mediocre and bad things, but his power of judgment, sharpened and practiced to the highest degree, rejects, selects, knots together; as we can now see from Beethoven’s notebooks how the most glorious melodies were put together gradually and as it were culled out of many beginnings. He who selects less rigorously and likes to give himself up to his imitative memory can, under the right circumstances, become a great improviser; but artistic improvisation is something very inferior in relation to the serious and carefully fashioned artistic idea. All the great artists have been great workers, inexhaustible not only in invention but also in rejecting, sifting, transforming, ordering.Reminds me of this article in the New Yorker from last month. Austin Kleon's take on "The Neuroscience of Not Knowing".
Inspiration again. - If productive power has been blocked for a time and prevented from flowing out by an obstruction, there occurs in the end an effusion so sudden it appears that an immediate inspiration without any preliminary labour, that is to say a miracle, has taken place. This constitutes the familiar deception with whose continuance the interest of all artists is, as aforesaid, a little too much involved. The capital has only been accumulated, it did not fall from the sky all at once. Similar apparent inspiration is also to be found in other domains, for example in that of goodness, virtue, vice.
HAH, I, 155-156
I used to call these sorts of insights "boom" experiences, at least the experiences of clarity that were particularly astonishing. As time went on though it became more obviously a function of how my mind works. I guess I don't have any reason to consider it less astonishing simply because it became more familiar.