There is a horizontal advance between abrupt ascents. It is the moment of the abrupt ascent which gives you an impression of something like a revelation, a great inner joy. But once you have climbed the step, if you want to climb it once more you would have to go down again. You must go on preparing yourself at this level in order to climb another higher step. These things which suddenly give you a great joy are always ascents.
But these ascents are prepared by a slow work of horizontal progress, that is, one must become more and more conscious, establish more and more perfectly what one is, draw from it all the inner, psychological consequences, and in action also. It is a long utilisation of an abrupt leap and, as I say, there are two kinds of progress. But the horizontal progress is indispensable.
Ref: Questions and Answers 1955