Chaos, in Greek mythology, refers to the beginning of all things, it means a vast void, emptiness, abyss or infinite darkness. It also meant the birth of deities Chaos, Gaea, Tartarus and Eros. Chaos or Khaos is also viewed as the lower atmosphere surrounding earth in certain sources.
Around 2nd century AD, The Orphic Hymns first introduced the term Khaos. It was suggested that the universe was compressed into a giant Cosmic Egg, which erupted and formed the god, as well as Phanes, the primordial god, and Ouranos, the son of Nyx (night). First came, the ageraos (never aging) and Chronos (time), followed by the creation of Aether (air) and Chaos. Chronos and Aether then created the Cosmic Egg where in the 6th Orphic hymn, Chaos contracts into the Cosmic Egg. This concept of a Cosmic Egg appears in the creation myths of various religions including Hinduism, Finnish legends and even in Dogon (a primitive tribe from Mali) mythology. Hesoid’s Theogony introduces the concept as a formless, moving mass and the origin of god and cosmos.
According to Greek mythology, Hesoid’s view suggested it was not a definite thing and could represent formless matter and infinite space but Anaximander (610-546 BC), claimed the origin was aperion (infinite or unlimited) and believed it to be a perpetual substance from which everything originated and will return. Alchemists such as Blessed Raimundus Lullus identified the article as the matter created neither by God or Primal form whereas Swiss alchemist, philosopher and occultist, Parcelus, identified the Earth with Chaos.
Upon looking into primordial theory in Kabbala, there are five worlds that exist and sources cite the sefirot or Tohu (attributes) of chaos bring about diversity in these worlds, existing outside this world as they are unstable, shattered plains of reality. They are independent of each other and hence have no structure or order.
Chaoskampf is the legend of a hero who battles against a chaos monster generally in the shape of a dragon or serpent. Generated in a Proto-Indo-European culture this myth also has other variations such as Thor vs. Jörmungandr (Norse), Tarhunt vs. Illuyanka (Hittite), Indra vs. Vritra (Vedic), Fereydun vs. Aži Dahāka (Avestan), and Zeus vs. Typhon (Greek). The modern scientific meaning of the term chaos differs from the ancient Greek concept and its a reference to systems which have parameters guided by numerous hidden laws which can easily change and are therefore difficult to describe. The development of the theory of Chaos was introduced by Scientist Ilya Prigogine.