What is knowledge? Threefold: (1) of particulars and generals, sensible, empirical, literal, indicative, samvyavahārika-pratyakṣa, (2) of universals, rational or intelligible, allegorical, conventional, parokṣa, (3) of sameness, without image or likeness, transcendental, anagogic, aparokṣa = paramārthika-pratyakṣa. Of these the first two (avidyā) are relative, the last (vidyā) immediate and absolute, only to be expressed in terms of negation.
This epistemological query classically treats the Ātman (self, Self; Universal Man, Bráhman) -- māyā (creative power; magic; natura naturans)  doctrine from the aesthetic point of view. As it pertains: (1) the particular-general (sensible) and (2) universal (intellectual) characteristics being relative, mutable, illusory being māyā, and (3) the similitudine, evidently significant (paramārthika-pratyakṣa), immutable and Absolute being Ātman.
Of particular interest to one is the latter part of the above quotation, the notion that the absolute can only "be expressed in terms of negation"; the neti neti ("not this, nor that") of the Bṛhadāraṇyaka Upaniṣad , or as opens the Tào Té Chīng:
The tào that can be told is not the eternal Tào
The name that can be named is not the eternal Name.
The unnamable is the eternally real.
Naming is the origin of all particular things.
Ultimately Reality cannot be referred to directly, in and of itself in its entirety, because the conventional naming of things is categorically particular (avidyā), and the Eternal is not particular and cannot be reduced or divided. It is thus the grasping act, dominionization by the intellect which is itself the cause of confusion, relativity and pain (duḥkha). In other words, the Absolute can only be expressed in terms of negation because terms (namā, name, idea, form; means of conventional discrimination) and apparent aspect (rūpa, shape, natural shape, semblance, color, loveliness; image, effigy, likeness; symbol, ideal form; means of conventional discrimination) when taken as realities in themselves (trishna, tṛṣṇā, reification) inhibit the pure understanding of the Ultimate Reality. Duḥkha is this habitual self-inhibition.
The profundity of "terms of negation" lies in their symbolic, or rather non-symbolic, meaning. When conditioned action, kárma, "the type of action which always requires the necessity for further action"  -- the fingertip trying to feel itself, the ear trying to hear itself, the dog chasing his own tail -- is shown for its absurdity, the One becomes liberated from the ego. Watts on the teaching of the principals of Chán-Zen:
The basic position of Zen is that it has nothing to say, nothing to teach. The truth of Buddhism is so self-evident, so obvious that it is, if anything, concealed by explaining it. Therefore the master does not "help" the student in any way since helping would actually be hindering. On the contrary, he goes out of his way to put obstacles and barriers in the student's path. 
By such means the student is at last brought to a point of feeling completely stupid -- as if he were encased in a huge block of ice, unable to move or think. He just knows nothing; the whole world, including himself, is an enormous mass of pure doubt. Everything he hears, touches, or sees is as incomprehensible as "nothing" or "the sound of one hand." 
The "non-symbolic" meaning, in other words, is that to seek meaning is itself meaningless -- the source of duḥkha. Rather one should relinquish reliance upon māyā and allow the rhythmic spontaneity of life (dhvani: sound, sounding; overtone of meaning, resonance of sense, content as distinguished from intent) to permeate and winnow illusory habitual inhibitions and re-open the experience up to the quintessential flavor, rasa (savor, the substance of aesthetic experience, knowable only in the activity of tasting, rasasvadana), of Reality as such, as it has always been.
The breaking-down of kárma, the "habitual way of consciousness" , is liberation from duḥkha, the pain of relativity, temporality, death and birth. All pure meditation results in such an unveiling, wherein the act of grasping is let go of and one is allowed to simply be, nirvāṇa. To seek this perennial state of being is to loose it. Precluding māyā, it is as such not an "end" to any "means"; it transcends such conventionalities; it is non-contriving and spontaneous.
Thus the only way to express the third and purest form of knowledge is by not trying to express it at all, or by negating the forces of its elongation or besmirchment, a "meaningless-meaningfulness" or "meaningful-meaninglessness", and the only way to truly "know" it is to remember that the spontanious Absolute already is you, and you it; that all knowledge in its relative and conventional sense is not Absolute Knowledge; that "The tào that can be told is not the eternal Tào."
And all things written, here or elsewhere, are essentially useless wastes of time unless that dhvani rings through it to the inner Bráhman, and he tastes (rasa) that immediate quintessential similitude, vidyā, formless and un-nameable. Though this is nigh impossible without true understanding of the triune epistemological nature: sat-cit-ānanda, existence-consciousness-bliss, being-intelect-union. In other words, one must understand knowing, that which is known and knowledge itself as one in the same. The difficulty of this concept to the Occidental mind is put thus by Nietzsche in Beyond Good and Evil, Part Three, 54:
They said “I” is the condition, “think” is the predicate and conditioned—thinking is an activity for which a subject must be thought of as cause. Now, people tried, with an admirable tenacity and trickery, to see whether they could get out of this net, whether perhaps the opposite might not be true: “think” as the condition, “I” the conditioned—thus “I” is only a synthesis which is itself created by thinking.
This critique is absent the union of thought itself. That is, "thinking", "thinker" and "thought" occur simultaneously, interdependently. It is only the notion of the Ego, the "I", and its passage through a perceived liner time (rather than an ever present now) which upsets and brings an Absolute to a relative.
An impoverished point of view where manifestation of Knowledge in its complete sense is befuddled, where there is seemingly no savior from māyā because of an habitual adherence to distinction of Being from Intellect, separateness, avidyā, is a Western condition:
What is implied is that a recognition of the principles by which the East still lives, and which can, therefore, be seen in operation (and few will question that peoples as yet "unspoiled" are happier than those that have been "spoiled"), could lead the modern "world of impoverished reality," in which it is maintained that "such knowledge as is not empirical is meaningless," back to the philosopher who denied the dependence of knowledge on sensation and maintained that all learning is recollection. 
One can only hope, in the modern West, that his work, in as much as he is bound to kárma, resonates with that Cosmic Rhythm, dhvani, of the eternal Ātman, that others might get a taste (rasa) of the bliss of Eternity.
It may be a dewdrop,
And yet--and yet-- 
1. All Sanskrit translations are provided ibid, Sanskrit Glossary, pp. 217-229.
2. "The form of that person is like a cloth dyed with turmeric, or like grey sheep’s wool, or like the scarlet insect called Indragopa, or like a tongue of fire, or like a white lotus, or like a flash of lightning. He who knows this-his splendour is like a flash of lightning. Now, therefore, the description of Bráhman: “Not this, not this” (Neti, Neti); for there is no other and more appropriate description than this “Not this.” Now the designation of Bráhman: “The Truth of truth.” The vital breath is truth and It (Bráhman) is the Truth of that."
3. Alan Watts, The Way of Zen, Random House Publications, p. 46
4. Ibid, p. 163
5. Ibid, p. 166
6. Katsuki Sekida, Zen Training, John Weatherhill, inc.
7. A. K. Coomaraswamy, The Bugbear of Literacy, Perennial Books Ltd., p. 25
8. Haiku written by Issa upon the death of his child.