Reality precedes us: we discover it rather than invent it. Belief precedes knowledge, and metaphysics precedes epistemology. That is realism. Nevertheless, experience and thought can lead to revision of belief, which is the way of science.
Anti-realists make the mistake of limiting reality to what they know, and so limiting belief to knowledge. But they ignore their own prior beliefs and wrongly think of themselves as neutral observers and unbiased participants. They may retreat to a position of nonbelief, as if that were possible.
There is no knowledge without prior belief, at least provisionally. Prior belief may be like common sense or like a postulate or hypothesis. It must first be asserted to find its implications for inductive exploration. The conclusion of induction is new belief, expressed in definitions and principles, which forms the basis for deductive exploration.
There is no society without prior loyalties, such as blood and soil, language and custom. There is no religion without prior revelation, such as from a prophet or shaman or charismatic leader. There is no economy without prior exchange, such as between neighbors or tribes.