From The Art Spirit (1923), by Robert Henri.

There are moments in our lives, there are moments in a day, when we seem to see beyond the usual–become clairvoyant. We reach then into reality. Such are the moments of our greatest happiness. Such are the moments of our greatest wisdom. It is in the nature of all people to have these experiences; but in our time and under the conditions of our lives, it is only a rare few who are able to continue in the experience and find expression for it.