The Nyaya-sutras assert the premise that "all knowledge is not intrinsically valid", that "most knowledge is not valid unless proven" and "truth exists whether we human beings know it or not". However, states Fowler, the text accepts the foundation that "some knowledge is self evident" and axiomatic in every field of knowledge, which can neither be proven nor needs proof, such as "I am conscious", "I think" and "soul exists". Furthermore, the text presents its thesis that knowledge is not self-revealing, one must make effort to gain knowledge and this is a systematic process that empowers one to learn correct knowledge, and abandon incorrect knowledge.