When a mind has a tendency towards day-dreams, it's a mistake to shield it from them, to ration them. So long as you divert your mind from its day-dreams, it will not know them for what they are; you will be the victim of all sorts of appearances because you will not have grasped their true nature. If a little day-dreaming is dangerous, the cure for it is not to dream less but to dream more, to dream all the time. One must have a thorough understanding of one's day-dreams if one is not to be troubled by them....
(Marcel Proust, Within a Budding Grove, In Search of Lost Time; trans. Moncrieff, Kilmartin, and Enright)
Here the character speaking is the painter Elstir, relaying this information to our day-dreaming narrator at his studio in seascape vistas of Balbec. He almost comes off as a Platonist in his desire to move from the appearances of things to the things themselves, but the true nature here to be grasped is not the form or idea of the good or beautiful, but the true nature of something that is inherently evanescent, something that cannot have permanence nor a static nature: a day-dream. Indeed, can a day-dream or the nature of day-dreaming be grasped at all, or is it something more like sand--the tighter you grasp the more of it will slip through your fingers? The more you pursue a day-dream, the faster it slips away. If one is to face it, perhaps the best thing to do is to merely linger, and to let it thicken around you like a mist.