Edward Roer (Translator), Shankara's Introduction - Google ブックス to Brihad Aranyaka Upanishad at pages 1-5;Quote - "The Vedas are divided in two parts, the first is the karma-kanda, the ceremonial part, also (called) purva-kanda, and treats on ceremonies;the second part is the jnana kanda, the part which contains knowledge, also named uttara-kanda or posterior part, and unfolds the knowledge of Brahma or the universal soul."
mkgandhi.org
MK Gandhi, The Essence of Hinduism, Editor:VB Kher, Navajivan Publishing, see page 3;According to Gandhi, "a man may not believe in God and still call himself a Hindu."
Julius J. Lipner(英語版) (2009), Hindus:Their Religious Beliefs and Practices, 2nd Edition, Routledge, ISBN 978-0-415-45677-7, page 8;Quote:"(...) one need not be religious in the minimal sense described to be accepted as a Hindu by Hindus, or describe oneself perfectly validly as Hindu. One may be polytheistic or monotheistic, monistic or pantheistic, even an agnostic, humanist or atheist, and still be considered a Hindu."
Flood, Gavin, ed. (2003), The Blackwell Companion to Hinduism, Blackwell Publishing Ltd., ISBN 1-4051-3251-5, see Michael Witzel(英語版) quote on pages 68-69
Patrick Olivelle(英語版) (2014), The Early Upanisads, Oxford University Press, ISBN 978-0195352429, page 3;Quote:"Even though theoretically the whole of vedic corpus is accepted as revealed truth [shruti], in reality it is the Upanishads that have continued to influence the life and thought of the various religious traditions that we have come to call Hindu. Upanishads are the scriptures par excellence of Hinduism".