Universals are a major topic in metaphysics concerned with whether general properties or categories exist independently of the individual things that exemplify them. For example, many objects may be described as red, but metaphysical inquiry asks whether redness itself has some form of existence beyond those particular objects. Debates about universals connect with particulars, properties, identity, essence, classification, realism, and nominalism, and they address how general concepts relate to the individual entities encountered in experience.