Intuition. Aha. Flash. Revelation. Inspiration. Curiosity. Something itching deep within us that we know is there but can’t quite scratch but know we must scratch. A combination of these, plus an edge of fear.
“Sometimes we see a kind of truth all at once, in a flash, as a whole. We grasp it in a block, in its wholeness, but not in its details. We see its whole perspective, and as long as this truth stands vividly before us, we contemplate it and seem to understand it. We do not understand it at all thoroughly, yet we know it with some certainty, although vague, rough, and in outline. This is especially true of philosophical and religious ideas.
But once this general figure has become our property and, we think, part of us, in this first easy-seeming intuition, and we store it in our minds and take it for granted, then, by a new series of minute, difficult, toilsome steps we begin to find out, elaborately and with a great deal of trouble, different things that are only details of this same big idea, and aspects of it, and parts of it. Thus after seeming to catch the whole idea at once, easily, we go over the whole thing again and rediscover it with great difficulty in all its parts. And this may take months or even years.
We never really begin to understand the idea until this more arduous and discouraging process gets under way and, in this process, we seem to live the idea, working it out in our own experience in the manner appropriate to our own sad, contingent and temporal state where nothing is possessed except successively, in scraps and in pieces.
Yet we always long to possess truth as it is in the Mind of God and He sometimes gives intuitions that seem to imitate, in their completeness, His own knowledge, but their function is to lead us really to know what we think we know from these intuitions, by making them more complete in our own grubbing and rag-picking fashion, after the first intuition. So we sit and think, like men whose houses have burned down grubbing in the ashes for something that might have been saved, until we find some diamond that had been buried in the wall for centuries . . .”
 From the Secular Journal of Thomas Merton, entry dated April, 9, 1941, as a young man on an Easter retreat at Gethsemani, discerning his vocation to monastic life.