Buddhism vs. Hinduism, Non-Self vs. Cosmic Self… 

Anatta/anatman (non-self) doesn’t mean that we are nothing, just not much: no permanent soul, certainly nothing cosmic like Brahman. And this is where the fundamental concept comes from, the debate with the Brahmanists that we now call Hindus, though at that time (500BCE) the term was unknown, at least to Indians themselves. Because that’s all that the term ever meant, really: people of the Indus River, i.e. Sindhu or Hindu, a river now identified with Pakistan. India is now more identified with the Ganges.  

But the distinction that the Buddha wanted to make between his worldview and that of the Brahmanists was that he saw nothing like the cosmic Atman ‘self’ that they propose to unite with the equally cosmic Brahman god-stuff that exists as the creative principle of the Universe. And while Hindus recognize Buddhism as but one of many Hindu Veda-based sects, Buddhism is having none of that, and the self/non-self debate is at the heart of that issue.  

In fact, Buddhism relegates ‘self’ to ‘heaps’ of random qualities called ‘skandhas’ or ‘khandhas’ in Sanskrit or Pali. They are form, feeling, perception, consciousness, and reasoning, of which we all share equal and certain quantities. No one collection of such qualities is more important than any other, just as no one person is better than any other. The racist caste system of India will forever define the difference between Hinduism and Buddhism, and the atman/anatman distinction is at the heart of that.