Mervyn Peake on Comprehension

Who can say how long the eye of the vulture or the lynx requires to grasp the totality of a landscape, or whether in a comprehensive instant the seemingly inexhaustible profusion of detail falls upon their eyes in an ordered and intelligible series of distances and shapes, where the last detail is perceived in relation to the corporate mass?

It may be that the hawk sees nothing but those grassy uplands, and among the coarse grasses, more plainly than the field itself, the rabbit or the rat, and that the landscape in its entirety is never seen, but only those areas lit, as it were with a torch, where the quarry slinks, the surrounding regions thickening into cloud and darkness on the yellow eyes.

Whether the scouring, sexless eye of the bird or beast of prey disperses and sees all or concentrates and evades all saving that for which it searches, it is certain that the less powerful eye of the human cannot grasp, even after a life of training, a scene in its entirety. No eye may see dispassionately. There is no comprehension at a glance. Only the recognition of damsel, horse, or fly and the assumption of damsel, horse, or fly; and so with dreams and beyond, for what haunts the heart will, when it is found, leap foremost, blinding the eye and leaving the main of Life in darkness.

--from Chapter 20 of Mervyn Peake's Titus Groan.