The topic of this thesis is 〈Comparison between four levels of Ātmansya caturpādāḥ vādaḥ in Chādogya UPaniṣad and the idea of Nirātrianin Original Buddhism〉. In there, the word “Ātmansya caturpādāḥ vādāḥ” means the soul（ātman） itself can be divided into four levels. The word “Ātman” means the deeply part of soul in every human being. Meanwhile, the four levels of soul are, 1.”the bodily soul”（śārīre ātman；in Buddism means the skandha of rūpa); 2.” tire dreaming soul” （svapne ātman； in Buddism means the skandha of vedāna, saṁjñā, saṁskāra and vijñāna); 3.” the no dreaming soul” (asvapne ātman)； 4.”the ultimate soul”(paramātman).
Since, the research of soul must jump up into difference levels before reaching to the level of “ultimate soul”, so many scholars of Buddhist study may think that the theory of nirātman does not the full refutation of the four levels of soul in Chāndogya Upaniṣad. If we deeply study about the Saṁyukta Āgama or Saṁyutta Nikāya, we may find out that the refutation of the Soul in the period of Original Buddhism (B.C.550-B.C.3O0)only reaching to the first two levels of the soul. Meanwhile, the research of the third level of the no dreaming soul must begin in the period of Scholastic Buddhism(B.C.300-A.D.100), it had raised up the discussion about the Sudject of Saṁsāra and also the Sudject of Nirvāṇa. At that moment, it reproduced the philosophy of“non saskandha and also non viskandha pudgala vāda” in Vātsuputriya. The aim of my paper is trying to lock out the sphere of Nirātman in Original Buddhism and avoiding the dictatorship of the refutation of all souls.
