Literally, the word demiurge means “public worker” or “public craftsman.” The Greek word from which it comes was originally used to denote a person such as an artisan who had a special skill and fulfilled a special function in society. Over time the term came to refer to a deity of sorts; in some philosophies and religions, the Demiurge is a subordinate god who was involved in the creation of the universe. The Demiurge is seen as the Great Artificer or the Grand Architect of the Universe.
Plato was one of the first to discuss the Demiurge as the being responsible for the production of the universe. According to Plato, the Demiurge fashioned and shaped the material universe. This being was good, but the world is flawed because the Demiurge did not have much to work with—despite the Demiurge’s best intentions, the world is imperfect.
In Gnosticism, the Demiurge is not good at all. Rather, the Gnostic Demiurge is a proud, bungling fool who created the material world against the wishes of the Supreme God. In this way the Gnostics consider all material things evil—the physical world is the product of a hostile Demiurge—and all spiritual, incorporeal things good.
Some Gnostics identify the Demiurge as the God of the Old Testament and place him at odds with the God of the New Testament. Other Gnostics, specifically those in the Valentinian school of thought, identify the Demiurge not as an evil being but as a benevolent (albeit rather ignorant) spirit who rues the fact that the world is corrupt. In Valentinian Gnosticism, the Demiurge is himself redeemed and participates in the redemption of humanity as well.
There is nothing biblical about the concept of the Demiurge. The Bible presents God as the sole Creator of heaven and earth (Genesis 1); there are no subordinate gods, and the earth was not formed by a stupid (or evil) spirit. The Creator spoke the universe into existence; He did not form it out of pre-existing material. The world is corrupt due to man’s sin (Romans 5:12; 1 Corinthians 15:22), not because of the sloppy (or malicious) work of a spirit being. The Bible does not present two gods in the Old and New Testaments but one God advancing His single plan of redemption through the ages. Platonism and Gnosticism do not represent the truth.