Luminous Clouds. An interesting analogy.
At dusk and dawn the sky often turns a brilliant and beautiful deep orange-red. As is generally known, this is caused by water vapour in the atmosphere. But when the Sun is high this brilliant and beautiful hue vanishes and leaves behind a not quite perfectly clear sky. It is not a deep blue, and the air is heavy and saps the energy leaving the mind and body dull and drained of energy.
On other occasions, the sky may be completely clear at dusk and dawn . This is no doubt caused by the complete absence of water vapour in the atmosphere. And when, in this case, the Sun is high the result is a perfectly clear sky. It is a deep blue, and the air is light and charged with energy giving the mind and body enormous vitality.
This is a good analogy to the mind in an advanced stage of mindful clarity, where greed & hate are absent & only the dullness of delusion remains: a subtle kilesa sparkling in the energy of the focused mind.
If the practitioner develops his mindfulness according to knowing the knowable as knowable: the unknowable as unknowable. Staying with the Knowing, always asking " . . . if this (subjectivity) is the Knowing then what is it that knows . . . ": this meditator will, in the due course of time, come to a stage where the mind becomes brilliantly bright and radiant. It will have a very seductive appeal and seem quite wonderful and this state can be seen to be analogous to the red sky at dusk or dawn. But the question remains: " . . . if this is me, then who is it that knows? . . . ". Such a question will objectify and thus release this energy, giving way to a state of mind where the only thought that can harmonise with it will just be " . . . knowing . . . ". The mind in this state is quite clear and free. All other thought ceases and if forced will only jar the system: even " . . . knowing the knowing . . . " will seem inappropriate. Just " . . . knowing . . . " is all that will fit here. This state is most enjoyable and is analogous to the clear blue sky at dusk and dawn, with its sense of lightness, freedom and energy.