Being is one of the most fundamental concepts in metaphysics and ontology, referring broadly to the fact or condition of existence. Philosophical inquiry into being asks what it means for something to be, whether different kinds or modes of being can be distinguished, and how being relates to concepts such as existence, essence, identity, substance, and reality. Questions about being often underlie broader metaphysical discussions because they address the most basic issue of what it means for anything to exist in the first place.