The problem of universals is an ancient question from metaphysics that has inspired a range of philosophical topics and disputes: "Should the properties an object has in common with other objects, such as color and shape, be considered to exist beyond those objects?

The American linguist Joseph Greenberg proposed a set of linguistic universals based primarily on a set of 30 languages.

a book by Donald Brown, an American professor of anthropology (emeritus) who worked at the University of California, Santa Barbara.

Aristotle's Theory of Universals is Aristotle's classical solution to the Problem of Universals, sometimes known as the hylomorphic theory of immanent realism.