What are the arguments to show that the other Vedas are less authentic than the Rig Veda Samhita?

Question

It is a belief of some neo-Hindus or modern Hindus that the Rig Veda Samhita (RVS) is the true scripture or foundational scripture of Hinduism, while the other Vedas like the Yajur Veda, etc. are less authentic.

This belief originates from western indologists who say that the rig veda was first composed, then yajus, then sama, and lastly atharva.

Moreover, they also claim that the Samhita portion of each Veda is more authentic than the other portions like Brahmanas, Aranyakas, and Upanishads especially.

From this it follows that the other Vedas have to be interpreted in accordance with the Rig Veda Samhita, and some even go so far as to say that those Vedas have interpolated verses, since the content of those verses is supposedly not mentioned in the RVS.

For example, the Yajur Veda purusha sukta (PS) hymn has extra verses than the RVS PS hymn. In those extra verses, one verse states that Lakshmi is the wife of the Purusha. But since these extra verses are not mentioned in the RVS PS hymn, it is concluded that it is an interpolation.

Second of all, "less authentic" does not mean "not authentic", and so it would still be "authentic". So then why not accept the PS of the yajur veda?

My question is, what is the basis for asserting that these Vedas are "less authentic" than the RVS?

As a matter of fact, no ancient Vaidika or Rishi has ever asserted that the other Vedas are less authentic than the RVS. Scholars like Vyasa, Jaimini, Shabara, Adi Shankara, and Kumarila Bhatta all hold that all four Vedas are equally authoritative since they are all apaurusheya.

So what are the arguments to show that the other Vedas are less authentic than the Rig Veda Samhita?

Answer 1

The authenticity and apauruṣeyā nature of Atharva Veda was questioned even by Mīmāṁsakas. These are their main arguments (pūrvapakṣa) according to Jayanta Bhaṭṭa of Nyāya school:

An objection to the validity of the Atharva Veda

1. the Ṛg Veda, the Yajur Vedas and the Sāma Veda teach us interrelated subject-matters. Hence we infer that these three Vedas have been composed by the same author. They are the source of valid knowledge as it is an inference that they owe their existence to one and the same author. But the Atharva Veda is entirely different from the above three Vedas since it has no concern with the religious rites mentioned in them. For this very reason it cannot be a source book of the religious rites. The Ṛg Veda, the Yajur Veda and the Sāma Veda enjoin the biggest religious acts such as the Soma-sacrifices Jyotiṣṭoma etc. Instructions regarding these sacrifices have been given in the different recensions of the Vedas. The Brahmins who are well-versed in these three Vedas can only take part in the observance of these rites. Therefore, the Vedas which enjoin such religious acts are only valid. The Atharva Veda is not so.

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2. Śruti and Smṛti bear evidence to the above view.
   
   

   1. The passages quoted from the Taittirīya Brāhmaṇa (III. 12. 9. 1), the Śatapatha Brāhmaṇa (XI. 5. 8. 1-3) and the Nārāyaṇa Upaniṣad corroborate this view. The relevant portion in the passages is that they refer only to the three Vedas.
      
      
   2. The Saṃhitā of Manu strengthens this view. The Saṃhitā says that one should observe the vow of celibacy for a period of twelve years in order to study the different Vedas. A Vedic student should reside in the house of his preceptor for 36 years, and read the three Vedas viz., the Ṛg Veda, the Yajur Veda and the Sāma Veda. He should thus observe the vow of religious study. Manu has also stated in his section on funeral ceremony that one who performs funeral ceremony should earnestly feed Brāhmaṇas who have made a complete study of the Ṛg Veda, the Yajur Veda and the Sāma Veda together with the corresponding Brāhmaṇas and the different recensions of the Vedas. Manu makes mention only of those Brāhmaṇas who have made a complete study of the three Vedas as entitled to the funeral feast. But he does not make mention of the Brāhmaṇas who have studied the Atharva Veda. Nay, in some cases, prohibition is noticed. A Brahmin who is well-versed in the Atharva Veda should not be invited to do this and that act.