“The most important, the central characteristic in which all fully developed mystical experiences agree, and which in the last analysis is definitive of them and serves to mark them off from all other kinds of experiences, is that they involve the apprehension of an ultimate nonsensuous unity in all things, a oneness or a One to which neither the sense nor the reason can penetrate.”

2002

Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 188.

Upon the Sovereign Sun (362)
Context: That divine and all-beauteous World, which from the highest vault of Heaven down to the lowest Earth is held together by the immutable providence of God, and which has existed from all eternity, without creation, and shall be eternal for all time to come, and which is not regulated by anything, except approximately by the Fifth Body (of which the principle is the solar light) placed, as it were, on the second step below the world of intelligence; and finally by the means of the "Sovereign of all things, around whom all things stand." This Being, whether properly to be called "That which is above comprehension," or the "Type of things existing," or "The One," (inasmuch as Unity appears to be the most ancient of all things), or "The Good," as Plato regularly designates Him, This, then, is the Single Principle of all things, and which serves to the universe as a model of indescribable beauty, perfection, unity, and power. And after the pattern of the primary substance that dwells within the Principle, He hath sent forth out of Himself, and like in all things unto Himself, the Sun, a mighty god, made up of equal parts of intelligible and creative causes. And this is the sense of the divine Plato, where he writes, "You may say (replied I) that I mean the offspring of the Good, whom the Good has produced, similar to itself; in order that, what the Good is in the region of intelligence, and as regards things only appreciable by the mind, its offspring should be the same in the region that is visible, and in the things that are appreciable by the sight." For this reason I believe that the light of the Sun bears the same relation to things visible as Truth does to things intelligible. But this Whole, inasmuch as it emanates from the Model and "Idea" of the primal and supreme Good, and exists from all eternity around his immutable being, has received sovereignty also over the gods appreciable by the intellect alone, and communicates to them the same good things, (because they belong to the world of intelligence), as are poured down from the Supreme Good upon the other objects of Intelligence. For to these latter, the Supreme Good is the source, as I believe, of beauty, perfection, existence, and union; holding them together and illuminating them by its own virtue which is the "Idea" of the Good.

Letter Seven (14 May 1904)
Letters to a Young Poet (1934)
Variant: For one human being to love another human being: that is perhaps the most difficult task that has been given to us, the ultimate, the final problem and proof, the work for which all other work is merely preparation.
Source: The Selected Poetry of Rainer Maria Rilke
Context: People have (with the help of conventions) oriented all their solutions toward the easy and toward the easiest side of the easy; but it is clear that we must hold to what is difficult; everything alive holds to it, everything in Nature grows and defends itself in its own way and is characteristically and spontaneously itself, seeks at all costs to be so and against all opposition. We know little, but that we must hold to what is difficult is a certainty that will not forsake us; it is good to be solitary, for solitude is difficult; that something is difficult must be a reason the more for us to do it.
To love is good, too: love being difficult. For one human being to love another: that is perhaps the most difficult of all our tasks, the ultimate, the last test and proof, the work for which all other work is but preparation.

The Bicycle Rider In Beverly Hills (1952)

Neither Democrats, Nor Dictators: Anarchists (1926)

Source: The Limits of Evolution, and Other Essays, Illustrating the Metaphysical Theory of Personal Ideaalism (1905), The Limits of Evolution, p.17-8

Genes and Sexuality: An Exchange (1995)

Georg Wilhelm Friedrich Hegel, Lectures on the Philosophy of History Vol 3 1837 translated by ES Haldane and Francis H. Simson) first translated 1896 P. 128
Lectures on the Philosophy of History (1832), Volume 3