The aristic thrust and conception of "contra natura" lie in our power finitely to extend our self-mastery, to GROW in will and spirit; but as Nietzsche repeatedly teaches in ZARATHUSTRA, such ends must be WILLABLE, achievable. There is nothing to be learned from the human-all-too-human impulse for self-deification or wholesale transcendence over the vicissitudes of life -- even though this aims at something contra natura, it is not truly concretely WILLABLE, it is just a fantasy of our imagination. We cannot BECOME a God. But we can learn to hold our deepest passions in check for the sake of a higher morality, if indeed we are aristoi. Willing and valuing must become an art, must be made consonant or coherent with the fabric of our natures. Mere megalomaniacal extravagance does not truly increase our charge of concentrated power; on the contrary it fires up our ambition with inflationary abstractions that give no traction or purchase to our actual wills. That way lies radical frustration and a metaphysics of depression: an inevitable life-pattern of self-delusion, as we suffer over and over from the necessity that "it would not be better if men got what they wanted," and yet will not permit ourselves ever to see or to learn anything from this self-deception and self-betrayal.
Aimed at as something terminal or ultimate or absolute, quiescence is, from the standpoint of life, a form of death, a stillness and inertia, an impassivity. Life is infinite sensitivity to all things, the quicksilver sympatheticism of everything that belongs in the natural cosmos. The mind and will do close out or exclude extraneous distractions as a means to their powers of self-concentration ("Thinking is a momentary dismissal of irrelevancies," Buckminster Fuller). But Buddhism makes this quiescence not a means but an end in itself, incompatible as it may be with the very life of spirit and of will. Taken as a mere exercise or tonic, it has an utterly different value of course.
The essence of human spirit would seem to be something static to Buddha: if it has an internal imperative to become something else (something higher or more spiritual), what self-disequilibrium could it suffer from that could nonetheless still be considered spiritual in Buddha's eyes? Nietzsche sought to explain this imperative for self-acculturation, for achieving rational self-mastery, for spiritualization, for self-radicalization and self-sublimation, by means of a "Will to Power" far more comprehensive than moderns (with only the cheapest and most facile grasp of "power") can understand. As a philhellene Nietzsche perceives and respects what the Greeks took for granted, that "power" above all else must be self-reflexive, an expression of aristic self-moderation (their anti-hybristic ethos and its correlative contempt for idiotia): "power" to the Greeks is moral and philosophical and cultural and political authority because it expresses itself in the hardest thing of all for humans to achieve, self-mastery.
Nothing in the matter-of-fact or finite order of experience is directly or obviously grounded in actual authoritative principles; phenomena do not permit us to see through them to their infinite preconditions, and certainly not even to comprehend or conceptualize what kinds of things those preconditions may be. It is only through holistic and variably stressed principles that we can see the formation or architectonics of finite realities, in accordance with those lawful and ordering forces. There is no empirical path to principles, no psychological route to values or ultimate duties or essential character: hundreds of millions of human beings may despair of not having "salvation" who do not and cannot ever comprehend what the issue even is, i.e. the onslaught of the finite order that threatens to make our ambiguously finite/infinite spirit into just another finite particle within the finite world. We have to be always carrying out our self-education dialectically, with one eye on each domain, the finite and the infinite, each of which demands its own peculiar modus of intelligence and insight from us.