I write from the first khanda of the first mundaka of the Mundaka Upanishad.
Shaunaka, the son of Shun, a great householder endowed with noble qualities and a pure heart, came with reverence to the great sage Angiras, bearing sacred fuel in his hands according to scriptural custom, seeking knowledge of Brahman. Humbly he asked: Blessed One, what is that supreme truth by knowing which, in its very essence, all that appears in this cosmos—all that can be seen, heard, and inferred—becomes known? I beg you to teach me that wisdom, so that I may come to know all things in this world.
(The question is remarkable. How many subjects there are to know in this world. Even if a man spent endless lives, infinite stretches of time, seeking knowledge one subject at a time, he could never exhaust them. Therefore, instead of laboring to know each thing separately, one must know that singular thing which, once known, reveals all knowledge. One must know the fundamental principle itself. The question arises: did Shaunaka know that such a thing exists—something that, once known, illuminates everything? He had heard of it, read of it in the scriptures; or perhaps he approached with only a general intuition—that all knowledge flows from one understanding. How did he know? When you know gold, you know all things made of gold. Though their shapes differ, their substance is one. The Chandogya Upanishad teaches this: know clay, and you know all things of clay, for their names vary only; apart from clay, they have no separate existence. Clay alone is real; multiplicity is merely nominal. Modification means only the various forms, known by various names, by various words. The scriptures offer many examples: know the material, and all objects fashioned from it are known. They differ in form, but their substance is one. Without that substance, they possess no independent reality; if they did, they would be truly separate entities. Modification cannot claim independent existence—therefore it is false. It is like the rope: a serpent appears in it, yet without the rope's reality, the serpent has no separate existence. Know the rope, and all that appears manifest in it is known. Some see it as a serpent, others as a stick, a garland of flowers, a stream of water, or a crack in the earth. Though it appears in different ways, apart from the rope it has no separate being. This is the conclusion.
Once the material cause is known, all its effects become known. In other words, there exists only one cause, and all effects are merely imposed upon it. If these effects possessed an independent reality, separate from their cause, then they would have their own existence. But take the clay away from a clay toy—does the toy remain? Remove the gold from an ornament—what is left of it? Nothing whatsoever. When we cannot conceive of an object's separate existence apart from its material cause or substratum, we call that unreal. Therefore, whatever transformations we perceive in this world—all these modified forms—are false; only the material cause itself, the original ground, is real. That cause is Brahman, or Being. In the beginning, the universe existed merely as undifferentiated being; nothing else existed but Being itself. Thus, when Brahman is known, all is known.
The word 'Brahman' carries a vast meaning. The fundamental principle pervading the entire universe, that which permeates and indivisibly interpenetrates the world itself—to know that is to know all that exists in the world; nothing remains unknown. How many kinds of objects exist in the world, and what endless diversity among them—why need we know each of them separately? The objects of knowledge are infinite in number; one could never finish knowing them all.
The scriptures counsel: there is no gain in wandering through such endless elaboration. Know the original cause, upon which all this diversity of the world rests. Names and forms are all illusory. One lifetime is insufficient to comprehend such vastness.
It is to know this fundamental material cause that Saunaka questions the teacher Angiras. He asks, 'Kasmin'—which is it? He has heard that by knowing one thing, all becomes known. Now he seeks special knowledge of that very thing.
The great sage Angiras then replied: those versed in Brahmic wisdom speak of two kinds of knowledge or learning that are worth knowing—one is the higher, the other the lower.
That is, knowledge of Brahman and knowledge of relative things, namely knowledge concerning the visible world. Of course, each kind of knowledge complements the other. Only when earthly knowledge is united with spiritual knowledge does ultimate knowledge arise. Earthly knowledge grants us temporary peace or joy, but spiritual knowledge alone can bestow lasting peace and joy. The scriptures call these two classes of learning aparā-vidyā and parā-vidyā.
Aparā-vidyā comprises the Rigveda, Yajurveda, Samaveda, Atharvaveda, Shikshā (phonetics), Kalpa (ritual procedures), Vyākaraṇa (grammar), Nirukta (etymology), Chandas (prosody), and Jyotisha (astronomy). (Why the sage explained aparā-vidyā first will be discussed later.)
The Vedas contain exhaustive descriptions of all things and subjects in the world, along with the various forms of ritual sacrifice and their fruits. The correct pronunciation and technique of vowels and consonants in Vedic recitation is called 'Śikṣā'—phonetics. The texts that lay out the procedures and methods of worship and sacrifice are known as 'Kalpa' (which also includes the Gṛhya-sūtras). The science that teaches the rules of Vedic and common speech, the process of word-formation through the classification of roots and suffixes, the varieties of semantic comprehension, and the regulations of word-usage is called 'Vyākaraṇ'—grammar. The Vedic lexicon that explains which word denotes which object and gives the reasons for such denotation is called 'Nirukta'—etymology. The science that distinguishes and classifies the meters of Vedic verse is called 'Chandas'—prosody. The knowledge that inquires into the positions and motions of planets and stars, and our relationship to them, is called 'Jyotiṣ'—astronomy. Thus the four Vedas and the six Vedic auxiliaries—these ten constitute aparā-vidyā, knowledge of the lower order.
But parā is that which leads to the attainment of 'Akṣara'—Brahman. It is parā that is unseen, ungrasped, without lineage, without color, without eye, without ear; it is parā that has no hands, no feet, is eternal, all-pervading, omnipresent, supremely subtle; it is parā that is immutable, the womb of all principles, and which the wise perceive everywhere.
Let us elaborate further. Only parā-vidyā, the science of Brahman, can reveal the nature of Parabrahman. There is no other way. The reason is this: the Brahmic principle transcends the reach of the senses of knowledge. It lies beyond the grasp of the organs of action—beyond all seizure. Without lineage or root, He is the cause of all; He Himself has no cause. He is eyeless, earless, handless, and footless. These qualities are negative in character. Yet alongside them stand positive attributes—He is eternal, pervading all, omnipresent, supremely subtle, immutable, and the womb of all beings.
The Supreme Brahman, the Supreme Lord, is not attained through the senses of knowledge, nor even through the organs of action. This Brahman is free from class distinctions and the limitations of lineage; free from the color-divisions of caste such as Brahmin and others; free from color in appearance and form. This Brahman is without eyes and ears and other sense organs, without hands, feet, and other organs of action. This Brahman is infinitely subtle, all-pervading, diffused everywhere as the inner Self, and eternally imperishable in every way. The wise experience this cause of all beings, fully present in all places.
The Śruti, the Upaniṣads, describe Brahman as the womb of the world, the source of all beings, the cause of the five elements. Through this we understand that Brahman alone is the material cause of the universe. Brahman is also the efficient cause. When the Muṇḍaka Upaniṣad speaks of the nature of the Immutable Person who must be known through parā-vidyā, it declares: this entire world-order has been born from the Immutable Person.
The logicians of the Nyāya school argued that like effects arise from like causes—as from inert matter arise various inert objects. But Brahman is conscious; the world is inert. How could the inert arise from the conscious? The Muṇḍaka Upaniṣad provides the answer: just as hair and body-hair grow from the human body, so too the substance of the world is born 'here'—from the Immutable. 'Here' means within one's own Self, in one's heart, in one's consciousness, in one's awareness. This is the meaning of Brahma-jñāna—the knowledge of Brahman. Thus the Muṇḍaka offers an illustration for the origination of the unconscious from the conscious.
Another objection arose — how did Brahman create without material cause? The Mundaka Upanishad answers once more: as a spider weaves its web from its own body, requiring no external material. And that very thread the spider draws back into itself.
The Nyaya school teaches that a single substance cannot be both the material cause and the efficient cause. The material cause of a pot is clay; its efficient cause is the potter. How then did Brahman create itself? The Mundaka Upanishad answers with an example: just as earth alone is both the material and efficient cause of medicinal plants (those herbs that fruit once and wither) — so too is Brahman. It bears noting that the Chandogya Upanishad also offers the spider as an illustration.
The Smritis that lie outside the Vedas possess no authoritative proof. Hence one might doubt whether, in classing certain teachings as lower knowledge, the Upanishads themselves stand outside the Veda and deserve no hearing; or whether, though part of the Veda, they fall outside the realm of higher knowledge. The truth is that "Veda" here denotes a body of words, not knowledge itself. Thus there is no contradiction in calling the knowledge born from the Upanishads — which constitute a portion of the Veda or the very purpose toward which the Veda aims — higher knowledge, even though the Upanishads themselves are part of lower knowledge.
Let me speak briefly. The sage Shaunaka once asked: "By knowing which one thing, does all become known?" In answer, it is shown concisely that from Brahman — the ultimate cause of all existence, the supreme Self — the world emerges plainly, along with the inner cosmos. This teaches that when one knows that omnipotent, all-knowing Lord, creator and sustainer of all; when one awakens one's own consciousness; when one establishes connection with one's own soul — then all becomes known.
In the sixth section, first chapter of the Chandogya Upanishad, the father-sage Aruni tells his son Svetaketu: "Did you receive from your guru that teaching by which all that has not been heard becomes heard; by which all that has not been reasoned out through logic and argument becomes reasoned and determined; by which all that is unknown becomes known; by which all the Vedas, sciences, and the rest are learned?" The first question of the Mundaka Upanishad and this question in the Chandogya Upanishad speak of one and the same thing. In truth, all Upanishads share this single aim: to know Him — to know oneself. To know whom is to know all; to attain whom is to attain all. Nothing remains unknown, nothing unattained. The satisfaction of knowledge is the fulfillment of all striving.
Though it is said that through higher knowledge (para-vidya) one comes to know oneself and Brahman, and that this is the supreme purpose of human life, yet lower knowledge (apara-vidya) too has its necessity. Apara-vidya also emanates from Brahman; the four Vedas and the six Vedangas, which fall within the domain of this knowledge, could never have been created had the awakening of the imperishable Brahman not occurred within the human soul or inner world. In the world, both the material cause and the instrumental cause are Brahman; similarly, both higher knowledge and lower knowledge emanate from Brahman. To be omniscient or all-knowing, one must know all things; knowledge itself is his sole austerity. Para-Brahman is the supreme state—that is, Brahman without attributes—and apara-vidya is a means toward union with Para-Brahman, which is apara-Brahman or Brahman with attributes. Brahman with attributes is also called Ishvara. In modern times we see that Totapuri initiated Sri Ramakrishna from Brahman with attributes (the worship of Kali) into Brahman without attributes. In the path of devotion, absorption into Brahman with attributes is considered the ultimate state. According to the science of devotion, the devotee eternally savors the divine form with all its particularity, for therein lies the devotee's fulfillment—the supreme attainment. Yet the non-dualists are not bound by any particular form. There, love, the lover, and the beloved are one—just as was the path and conviction of Swami Vivekananda. Both paths are true; each person should follow the path that is easier for them. That is why Sri Ramakrishna said of the Divine, one cannot say "this alone"; He is both without attributes and with attributes.
The knowers of Brahman say that one must know both higher and lower knowledge. Knowledge of the Supreme Self is higher knowledge—while lower knowledge comprises the study of dharma and adharma, their observance and fruits. At first glance it appears that Angira did not answer according to the question posed. Shaunaka had asked: by knowing which one thing does all become known? Instead of stating who is to be known such that all becomes known, Angira spoke of two kinds of knowledge. Yet there is no fault in this; the answer is actually sequential in nature. Apara-vidya is ignorance, and this ignorance must be negated—dissolved away. Knowing the subject matter of apara-vidya does not constitute knowing any thing in its essential, substantive nature. One must negate the prior position and settle it; then what remains as the conclusion must be stated. The conclusion was not indicated first; rather, having stated what is to be rejected, the conclusion is now being presented—first understand what apara-vidya is, know it, then, having freed yourself from it, pursue para-vidya. Therefore, before expounding higher knowledge, apara-vidya is expanded upon and explained.
The Upanishad itself declares that the study of apara-vidya—the Vedas, Upanishads, and Vedangas—is not sufficient unless higher knowledge is attained, that is, self-knowledge, knowledge of Supreme Brahman, knowledge of the Supreme Self, the contact and communion with God dwelling in the soul or with Consciousness itself. Apara-vidya degrades to a lower order of knowledge if it does not serve as a means to initiation into para-vidya. The aim of life is not to acquire apara-vidya, but rather, resting upon it, to acquire para-vidya—knowledge concerning the Supreme Self. If one cannot reach para-vidya (or self-knowledge or Brahman-knowledge), then the study of apara-vidya (and indeed of the Upanishads themselves) becomes utterly meaningless. With such bold conviction, and with unflinching honesty, the Upanishad has placed the awakening of Consciousness above the four Vedas and six Vedangas—which is truly unprecedented; thus there is no refuge more luminous than the Upanishad itself.
Footnote. Upanishad, Upanishad, and Upanishat—all three spellings are correct.