Nature then becomes known, not as a series of impressions on the retina of sense merely, but as a system seized by the eye of reason; for the senses show man the aspect worn by the world as it is at the moment, but reason opens to him the order obtaining in the world as it must be at every moment; and the instrument by which man rises from the phenomenal plane of experience to the necessary sphere of truth is the generalizing faculty whose operation has just been described.  The office of the reason in the exercise of this faculty is to find organic form in that experience which memory preserves in the mass,—­to penetrate, that is, to that mould of necessity in the world which phenomena, when they arise, must put on.  The species once perceived, the mind no longer cares for the individual; the law once known, the mind no longer cares for the facts; for in these universals all particular instances, past, present, and to come, are contained in their significance.  All sciences are advanced in proportion as they have thus organized their appropriate matter in abstract conceptions and laws, and are backward in proportion as there remains much in their provinces not yet so coordinated and systematized; and in their hierarchy, from astronomical physics downward, each takes rank according to the nature of the universals it deals with, as these are more or less embracing.

The matter of literature—­that part of total experience which it deals with—­is life; and, to confine attention to imaginative literature where alone the question of idealism arises, the matter with which imaginative literature deals is the inward and spiritual order in man’s breast as distinguished from the outward and physical order with which science deals.  The reason as here exercised organizes man’s experience in this great tract of emotion, will, and meditation, and so possesses man of true knowledge of himself, just as in the realm of science it possesses him of true knowledge of the physical world, or, in psychology and metaphysics, of the constitution and processes of the mind itself.  Such knowledge is, without need of argument, of the highest consequence to mankind.  It exceeds, indeed, in dignity and value all other knowledge; for to penetrate this inward or spiritual order, to grasp it with the mind and conform to it with the will, is not, as is the case with every other sort of knowledge, the special and partial effort of selected minds, but the daily business of all men in their lives.  The method of the mind here is and must be the same with that by which it accomplishes its work elsewhere, its only method.  Here, too, its concern is with the universal; its end is to know life—­the life with which literature deals—­not empirically in its facts, but scientifically in its necessary order, not phenomenally in the senses but rationally in the mind, not without relation in its mere procession but organically in its laws; and its instrument here, as through the whole gamut of the physical sciences and of philosophy itself, is the generalizing faculty.