Other scholars of Nyaya school reconsidered this question and offered arguments for what is God (Ishvara) and various arguments to prove the existence of "Ishvara". The 5th century CE Nyaya school scholar Prastapada, for example, revisited the premise of God. He was followed by Udayana, who in his text "Nyayakusumanjali", interpreted "it" in verse 4.1.21 of Nyaya Sutra above, as "human action" and "him" as "Ishvara", then he developed counter arguments to prove the existence of Ishvara, a reasoning that fueled the debate and disagreements on God in Neo-Nyaya and other Hindu traditions of 2nd millennium CE.