Ex nihilo is Latin for "out of nothing": when phrased as ex nihilo nihil fit, "nothing comes from nothing", it means that the universe was formed from eternal matter; as creatio ex nihilo, "creation out of nothing", it means that matter is not eternal but had to be created by some eternal uncaused cause, frequently defined as God. Creation ex nihilo is a theistic answer to the question of how the universe comes to exist: the Big Bang theory, by contrast, is a scientific theory; it offers no explanation of cosmic existence but only a description of the first few moments of that existence.
Theology
''Ex nihilo nihil fit'': uncreated matter
Ex nihilo nihil fit means that nothing comes from nothing. In ancient creation myths the universe is formed from eternal formless matter, namely the dark and still primordial ocean of chaos. In Sumerian myth this cosmic ocean is personified as the goddess Nammu "who gave birth to heaven and earth" and had existed forever; in the Babylonian creation epic Enuma Elish pre-existent chaos is made up of fresh-water Apsu and salt-water Tiamat, and from Tiamat the god Marduk created Heaven and Earth; in Egyptian creation myths a pre-existent watery chaos personified as the god Nun and associated with darkness, gave birth to the primeval hill ; and in Greek traditions the ultimate origin of the universe, depending on the source, is sometimes Okeanos, Night, or water. To these can be added the account of the Book of Genesis, which opens with God separating and restraining the waters, not creating the waters themselves out of nothing. The Hebrew sentence which opens Genesis, Bereshit bara Elohim et hashamayim ve'et ha'aretz, can be translated into English in at least three ways:
As a statement that the cosmos had an absolute beginning.
As a statement describing the condition of the world when God began creating.
As background information.
It has been known since the Middle Ages that on strictly linguistic and exegetical grounds option 1 is not the preferred translation. Our society sees the origin of matter as a question of crucial importance, but for ancient cultures this was not the case, and the authors of Genesis wrote of creation they were concerned with God bringing the cosmos into operation by assigning roles and functions. This was still the situation in the early 2nd century CE, but by that time Christian scholars were beginning to see a tension between the idea of world-formation and the omnipotence of God, and by the beginning of the 3rd century the tension was resolved, world-formation was overcome, and creation ex nihilo had become a fundamental tenet of Christian theology.
''Creatio ex nihilo'': the creation of matter
Creatio ex nihilo, in contrast to ex nihilo nihil fit, is the idea that matter is not eternal but was created by God at the initial cosmic moment. The concept is sometimes claimed to be present in a 2nd century BCE Jewish work called Second Maccabees, or in the 1st century CE Jewish philosopher Philo of Alexandria, but it seems to have originated around 200 CE in disputes between Christians, gnostics, and neo-Platonists, and by the 3rd century creation ex nihilo had become a fundamental tenet of Christian theology. Most modern biblical scholars are aware that scripture does not support ex nihilo creation, and consequently find other reasons for continuing to hold it. Some argue that it is indeed implied in scripture, even if never actually stated; others that it gains validity from having been held by so many for so long; and others find support in modern cosmological theories surrounding the Big Bang. Some examine alternatives to creatio ex nihilo, such as the idea that God created from his own self or from Christ, but this seems to imply that the world is more or less identical with God; or that God created from pre-existent matter, which at least has biblical support, but this implies that the world does not depend on God for its existence.
If the universe has a cause, then an uncaused, personal creator of the universe exists, who without the universe is beginningless, changeless, immaterial, timeless, spaceless, and infinitely powerful.
Therefore, an uncaused, personal creator of the universe exists, who without the universe is beginningless, changeless, immaterial, timeless, spaceless, and infinitely powerful.
In Jewish philosophy
The idea of creation ex nihilo was introduced into Judaism in the 10th century CE by Saadia Gaon, who in his work Book of Beliefs and Opinions imagined a God far more awesome and omnipotent than that of the rabbis, the traditional Jewish teachers who had so far dominated Judaism and whose God had created the world from pre-existing matter. Nachmanidies translates the hebrew word "Boro" as creation ex nihlio in the first verse of Genesis. This is how the Judaism has always translated creation and is described in Jewish mysticism. Today Jews, like Christians, tend to believe in creation ex nihilo, although some Jewish scholars recognise that Genesis 1:1 recognises the pre-existence of matter to which God gives form.
Islamic
Islam shares with Christianity and Judaism the concept that God is First Cause and absolute creator; he did not create the world from pre-existing matter.
