On the Sublime and Beautiful/Part IV/Chapter 10

IT may be objected to this theory, that the eye generally receives an equal number of rays at all times, and that therefore a great object cannot affect it by the number of rays, more than that variety of objects which the eye must always discern whilst it remains open. But to this I answer, that admitting an equal number of rays, or an equal quantity of luminous particles, to strike the eye at all times, yet if these rays frequently vary their nature, now to blue, now to red, and so on, or their manner of termination, as to a number of petty squares, triangles, or the like, at every change, whether of colour or shape, the organ has a sort of relaxation or rest; but this relaxation and labour so often interrupted, is by no means productive of ease; neither has it the effect of vigorous and uniform labour. Whoever has remarked the different effects of some strong exercise, and some little piddling action, will understand why a teasing, fretful employment, which at once wearies and weakens the body, should have nothing great; these sorts of impulses, which are rather teasing than painful, by continually and suddenly altering their tenor and direction, prevent that full tension, that species of uniform labour, which is allied to strong pain, and causes the sublime. The sum total of things of various kinds, though it should equal the number of the uniform parts composing some one entire object, is not equal in its effect upon the organs of our bodies. Besides the one already assigned, there is another very strong reason for the difference. The mind in reality hardly ever can attend diligently to more than one thing at a time; if this thing be little, the effect is little, and a number of other little objects cannot engage the attention; the mind is bounded by the bounds of the object; and what is not attended to, and what does not exist, are much the same in effect; but the eye, or the mind, (for in this case there is no difference,) in great, uniform objects, does not readily arrive at their bounds; it has no rest whilst it contemplates them; the image is much the same everywhere. So that everything great by its quantity must necessarily be one, simple and entire.