However, this assumption is wrong. The Āraṇyaka-texts are Vedic texts written with a different purpose. On the other hand, this is somewhat right in the sense that ,

“According to the other, and no doubt right, interpretation these works — all other books of the brāhmanic variety, subjects of instruction of Vedic schools — were to be imparted to and studied by advanced students in the solitude of the forest, because their contents were too sacred, too secret and esoteric, too uncanny and dangerous to be learnt in the villages. Their main subject was indeed, not only the explanation of the sacrificial rites, but the relevant texts themselves and their mystic and allegorical, ‘symbolical’ and ‘philosophical’ significance.

In fact the activities of yāga-yajña are the subject matter of the Brāhmaṇa texts, but the spiritual knowledge of Veda, Atmatatva (Self-knowledge) , Brahmatatva (knowledge of the Brahman)and the like, which are called jñanakāṇḍa, are the contents of Āraṇyaka at first, and then, of Upaniṣad. Yajña that is to be performed externally, using several equipments, as described in Brāhmaṇa-texts, has become Jñānayajña (yajna of knowledge) in the Āraṇyaka-texts.In the tenth chapter of the Śāṅkhāyana Āraṇyaka of Ṛgveda (Rigveda), the Agnihotra yāga of Brāhmaṇa texts — which involves so much of external rituals, has been described fully in spiritual terms.It is said that the Agnihotra of a Brāhmaṇa is actually the internal, spiritual Agnihotra. The Vedic Āhavanīya (Ahavaniya)agni and Gārhapatya (Garhapatya) agni have been conceptualised here as the Yogic forms of Prāṇa and Apāna vāyu residing in human bodies.And about the equipments of Agnihotra yajña, it is said that — śraddhā (sraddha; respect)is dugdha (milk), vākya is samit (the sacred piece of wood used for yajna), satya (truth) is āhuti (offering), and prajñā (prajna; wisdom)is ātmā (atma, the soul)
From this conception, it becomes clear that the grandeur of external yajña-rituals as described in the ‘Brāhmaṇa’ section of Veda, was transformed into internal yajña ad worship in the later Āraṇyaka texts. Afterwards, these would become the Jñānakāṇḍa (Jnanakanda)of Upaniṣad (Upanishad).

 

For each branch of Veda, there is one Āraṇyaka associated with it, for instance –
Ṛgveda -1. Aitareya Āraṇyaka (the Aitareya branch of Ṛgveda)
2.Kauṣitakī or Śāṅkhāyana Āraṇyaka (The Kauṣitakī or Śāṅkhāyana branch of Ṛgveda)
Yajurveda – 1. Taittirīya Āraṇyaka (the Taittirīya branch of Kṛṣṇayajurveda)
2. Maitrāyaṇīya Āraṇyaka (The Maitrāyaṇīya branch of Kṛṣṇayajurveda)
3. Kaṭha Āraṇyaka (the Kaṭha or Caraka branch of Kṛṣṇayajurveda)
4.Vṛhadāraṇyaka (the Mādhyandina or Kāṇva branch of Śuklayajurveda; the first nine paragraphs of the Mādhyandina branch is Āraṇyaka, and the last six paragraphs constitute the Upaniṣad part.
Sāmaveda Talavakāra Āraṇyaka or Jaiminīya Upaniṣad Brāhmaṇa (the Talavakāra or Jaiminīya branch of Sāmaveda)
Atharvaveda – No Āraṇyaka text. Gopatha Brāhmaṇa is considered as the Āraṇyaka part of this Veda.

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