section_path: Basic concepts/Being
section_name: Being
paragraph_text: Being
  
  Being, or existence, is the main topic of ontology. It is one of the most general and fundamental concepts, encompassing the whole of reality and every entity within it. In its widest sense, being only contrasts with non-being or nothingness. It is controversial whether a more substantial analysis of the concept or meaning of being is possible. One proposal understands being as a property possessed by every entity. Critics of this view argue that an entity without being cannot have any properties, meaning that being cannot be a property since properties presuppose being. A different suggestion says that all beings share a set of essential features. According to the Eleatic principle, "power is the mark of being", meaning that only entities with a causal influence truly exist. According to a controversial proposal by philosopher George Berkeley, all existence is mental, expressed in his slogan "to be is to be perceived".
  
  Depending on the context, the term being is sometimes used with a more limited meaning to refer only to certain aspects of reality. In one sense, being is unchanging and impermanent and is distinguished from becoming, which implies change. Another contrast is between being, as what truly exists, and phenomena, as what merely appears to exist. In some contexts, being expresses the fact that something is while essence expresses its qualities or what it is like.
  
  Ontologists often divide being into fundamental classes or highest kinds, called categories of being. Proposed categories include substance, property, relation, state of affairs, and event. They can be used to provide systems of categories, which offer a comprehensive inventory of reality in which every entity belongs to exactly one category. Some philosophers, like Aristotle, say that entities belonging to different categories exist in distinct ways. Others, like John Duns Scotus, insist that there are no differences in the mode of being, meaning that everything exists in the same way. A related dispute is whether some entities have a higher degree of being than others, an idea already found in Plato 's work. The more common view in contemporary philosophy is that a thing either exists or not with no intermediary states or degrees.
  
  The relation between being and non-being is a frequent topic in ontology. Influential issues include the status of nonexistent objects and why there is something rather than nothing.