While the primacy of the concept is responsible for these formal features of style, we must look elsewhere for the source of its vigor. Certainly another reason that Milton is a taxing author to read is the restless energy that permeates his substance. He never allows the reader to remain inert, and this is because there were few things toward which Milton himself was indifferent. One revelation of the active mind is the zeal and completeness with which it sorts things according to some scale of values; and judged by that standard Milton’s mind is active in the extreme. To approach this a little more systematically, what one discovers with one’s first reading of the prose is that Milton is constantly attentive to the degrees of things, and his range of valuations, extending from those things which can be described only through his elegant curses to those which require the language of religious or poetic eulogy, is very great. Indeed, “things indifferent,” to employ a phrase used by Milton himself, play a very small part in his writing, which rather tends to be juridical in the highest measure. And the vitality contributed by this awareness of difference he increased by widening the gulf between the bad and the good. These contrarieties are managed in various ways: sometimes they are made up of single nouns of opposed meaning; sometimes of other parts of speech or of phrases; but always it would take a dull reader to miss the opposed valuations. A sentence from The Doctrine and Discipline of Divorce will afford some good examples. Hence it is, that error supports custom, custom countenances error: and these two between them would persecute and chase away all truth and solid wisdom out of human life, were it not that God, rather than man, once in many ages calls together the prudent and religious counsels of men, deputed to repress the encroachments, and to work off the inveterate blots and obscurities wrought upon our minds by the subtle insinuating of error and custom; who, with the numerous and vulgar train of their followers, make it their chief design to envy and cry down the industry of free reasoning, under the terms of humor and innovation; as if the womb of teeming truth were to be closed up, if she presume to bring forth aught that sorts not with their unchewed notions and suppositions.[138] The vigor of this passage arises from a continuing series of contrasts, comprising the following: _error and custom_ with _truth and solid wisdom; God_ with _man_; _prudent and religious counsels_ with _encroachments_ and also with _inveterate blots and obscurities; subtle insinuating of error and custom_ with _industry of free reasoning_; and _womb of teeming truth_ with _unchewed notions and suppositions_. Here is another passage, from _Of Reformation in England_.