Every mantra of the four Vedās numbering twenty thousand or more was revealed to a human being called as a rişhi or rişhika when he/she was in a superconscient state. In the Rigveda, Sāmaveda and Atharvaveda, the names of the rişhis or rişhikās associated with the mantrās in the sūkta or hymn are listed in the heading along with the names of the metres associated with the mantrās and also the names of the associated cosmic powers, God (devi) or Goddess (devī).
It is not correct to state that rişhis composed the mantra. RV (1.164.39) declares that “the riks abide in the immutable supreme ether (parame vyoman) where are seated all the Gods (deva)”. The rişhi or rişhikā received the revelation of wisdom from this plane and transcribed it into verses or mantrās with appropriate words and metres. The process of transformation of the revelation into the verse is mentioned in many mantrās of Rig Veda. “They chanted the mantrās carved out of the heart RV (1.67.2)”; “O seers, the hymn-composer (mantra kŗtam ŗşhe) Kashyapa manifested (udvardhayan) the revelation (giraĥ) into the lauds (stomaiĥ), RV (9.114.2)”. See also the section on mantra for more details.
We may recall that Rig Veda Samhita has ten mandalās. Of them, the mantrās of six mandalās are associated with six great rişhis and their disciples: Mandala 2 with seer Ghŗtsamada, mandala 3 with the seer Vishvāmitra, mandala 4 with the seer Vāmadeva, mandala 5 with the seer Atri, mandala 6 with the seer Bhāradvāja and mandala 7 with the seer Vasişhţha. Garga Bhāradvāja is a seer of sixth mandala whose daughter is the famous Gārgi.
The sūktās in the remaining four mandalās are composed by several rişhis or rişhikās. The 191 sūktās of first mandala are composed by rişhis or rişhikās numbering roughly a hundred.
The first ten suktās are associated with the name of rişhi Madhuchhandas, disciple of the great seer Vishvāmitra. The eleventh sūkta is associated with Jeta, a disciple of Madhuchhandas.
Some of the names of the rişhis associated with first mandala are Romashā Brahmavādinī, Shunahshepa Ajigarti, Gotama Rahūgaņa, Agastya Maitrāvaruņaĥ, Dīrghatamas Auchitya, Praskaņva Kāņva, Kutsa Angirasa, Medhātithi Kāņva, Parāshara Shāktyaĥ, Paruchchhepa Daivodāsiĥ known for his use of the long metre atyaşhţi with 68 syllables and others. Typically the name of the rişhi along with his lineage is mentioned. For instance the seer Gotama belonged to the school of Rahūgaņa. Associated with the mandala 8 are Manur Vaivasvata, Medhatitiĥ Kāņva, Jamadagni Bhārgava, Pragatha Ghaura Kāņvaĥ, Matsyaĥ Sāmmadaĥ, Apālā Ātreyī, Sukakşha Āngīrasa etc. Associated with mandala 9 are Hiraņyastūpa Āngīrasa (whose name appears in mandala one also), Avatsāra Kāshyapaĥ, Shatam Vaikhānasaĥ, Renur Vaishvāmitra, Kakşhivān Dairghatamasa (who appears in mandala one also). The tenth mandala begins with the mantra of Trita Aptya; Some other rişhis or rişhikās there are Yamī Vaivasvatī, Aditi Dākşhāyinī, Vāg Ambhriņī, Savitrī Sūryā (rişhikā), Bhudaĥ Saumyaĥ, Mudgala Bhārmyashvaĥ, Yajnaĥ Prājāpatyaĥ, Prajāpati Parameşhţhī, Paulomī Shachī, Sarparājňī etc. The last hymn of the Rig Veda is by Samvanana Āngirasaĥ delineating universal harmony. We do not mention Sāmaveda separately since most of mantrās are in Rigveda and the same rişhis follow.
The entire Shukla Yajurveda was revealed to the seer Yājňavalkya.
Recall that the famous Vyāsa divided the single collection of mantrās into four Samhitās. The persons who carried out the compilation are Paila (Rigveda), Vaishampāyana (Yajurveda), Jaimini (Sāmaveda) and Sumantu (Atharvaveda). Note that Vyāsa and these other four persons did not have revelations of mantra. They are all compilers. Hence they are kāndarşhis.
Note that the Krişhņa Yajurveda has both rik mantrās and yajur mantrās. Every rik mantra has a metre, whereas the yajus is a rhythmic prose passage not bound by a metre. Krişhņa Yajurveda has about 700 mantrās from Rig Veda Samhita and their names are well known. The seers of the other mantrās from Krişhņa Yajurveda are not known with any degree of finality. Conjectures are there. The sages mentioned with Krişhņa Yajurveda are Vaishampāyana, Tittiri, Ātreya, Yāska etc., are all kāndarşhis.
The name of a rişhi indicates a psychological quality. Gotama means ‘most radiant’, Gavisthira means ‘steadfast in the light’. Bharadvāja means ‘those who are full of plenitude (vāja)’. Atri means ‘traveler or a destroyer of foes’, Vasişhţha is ‘one who is most oplent’, Vishvāmitra is ‘one who is friend of all etc.