Like elsewhere, in India too anti-idealists and materialists took practice as the main criterion of truth. Nyaya-Vaisheshikas were most outspoken in this regard, "after a knowledge is proved true in practice, there remains no doubt about the proof; hence the question of proving does not arise". On the other hand, the idealists believed in complete separation between theory and practice. They adhered to, in the words of Kumarila Bhatta, the principle of "bahyartha-sunyatva" (the unreality of the objects of knowledge), which, according to Debiprasad Chattopadhyaya, formed "the real pivot of idealism throughout its Indian career".