When we concentrate on a material object, whatever its situation, the very act of attention may lead to our involuntarily sinking into the history of that object. Novices must learn to skim over matter if they want matter to stay at the exact level of the moment. Transparent things, through which the past shines!
Man-made objects, or natural ones, inert in themselves but much used by careless life (you are thinking, and quite rightly so, of a hillside stone over which a multitude of small animals have scurried in the course of incalculable seasons) are particularly difficult to keep in surface focus: novices fall through the surface, humming happily to themselves, and are soon reveling with childish abandon in the story of this stone, of that heath. I shall explain. A thin veneer of immediate reality is spread over natural and artificial matter, and whoever wishes to remain in the now, with the now, on the now, should please not break its tension film. Otherwise the inexperienced miracle-worker will find himself no longer walking on water but descending upright among staring fish.