Wherever there is change, there is instability, and instability is proof of something the matter, of absence, deficiency, incompleteness. These are the ideas common to the connection between change, becoming and perishing, and Non-Being, finitude and imperfection. Hence complete and true Reality must be changeless, unalterable, so full of Being that it always and forever maintains itself in fixed rest and repose. As Bradley, the most dialectially ingenious Absolutist of our own day, expresses the doctrine "Nothing that is perfectly real moves." And while Plato took, comparatively speaking, a pessimistic view of change as mere lapse and Aristotle a complacent view of it as tendency to realization, yet Aristotle doubted no more than Plato that the fully realized reality, the divine and ultimate, is changeless. Though it is called Activity or Energy, the Activity knew no change, the energy did nothing. It was the activity of an army forever marking time and never going anywhere.
From this contrast of the permanent with the transient arise other features which mark off the Ultimate Reality from the imperfect realities of practical life. Where there is change, there is of necessity numerical plurality, multiplicity, and from variety comes opposition, strife. Change is alteration, or "othering" and this means diversity. Diversity means division, and division means two sides and their conflict. The world which is transient _must_ be a world of discord, for in lacking stability it lacks the government of unity. Did unity completely rule, these would remain an unchanging totality. What alters has parts and partialities which, not recognizing the rule of unity, assert themselves independently and make life a scene of contention and discord. Ultimate and true Being on the other hand, since it is changeless is Total, All-Comprehensive and One. Since it is One, it knows only harmony, and therefore enjoys complete and eternal Good. It _is_ Perfection.
Degrees of knowledge and truth correspond with degrees of reality point by point. The higher and more complete the Reality the truer and more important the knowledge that refers to it. Since the world of becoming, of origins and perishings, is deficient in true Being, it cannot be known in the best sense. To know it means to neglect its flux and alteration and discover some permanent form which limits the processes that alter in time. The acorn undergoes a series of changes; these are knowable only in reference to the fixed form of the oak which is the same in the entire oak species in spite of the numerical diversity of trees. Moreover, this form limits the flux of growth at both ends, the acorn coming from the oak as well as passing into it. Where such unifying and limiting eternal forms cannot be detected, there is mere aimless variation and fluctuation, and knowledge is out of the question. On the other hand, as objects are approached in which there is no movement at all, knowledge becomes really demonstrative, certain, perfect--truth pure and unalloyed. The heavens can be more truly known than the earth, God the unmoved mover than the heavens.