According to the Bible, there are only two sources of supernatural power. We can think of them as being "white" or "black" depending on from where they originate. The first source, white, comes from God. He allows righteous angels or humans to tap into his power but only if it is based on His will.
The second source of supernatural power is Satan and his demons (which those who practice black magic attempt to tap into) whom the Eternal (with restrictions) allows to use the power he gave them before they turned evil.
In spite of what many movies and television shows tend to promote, there does not exist a third, morally neutral or 'gray' source of power in the universe that someone can access (e.g. "the force" in Star Wars movies). This is a deception by the devil, who wants to deceive humans into accepting that there exist certain kinds of power, apart from God, that could be used for good.
Those who claim to be a "true" or "good" Psychic (or medium, witch, etc.) are either complete frauds or drawing their power from evil spirits. In spite of their protests, they practice black, and not white, gray or any other type, of magic.
Three explanations
Only three explanations exist for those who claim to have supernatural abilities and knowledge. The first is that they are complete frauds who deceive others into believing they have such power through humanly devised tricks.
Such imposters were the target of Harry Houdini in the 1920s, who sought to debunk physics, mediums, and others who claimed supernatural abilities. The second explanation is that the source of their abilities is from Satan and the demons (Revelation 13:13 - 14, 16:14, Deuteronomy 13:1). The final explanation is that they are a true prophet of God (Revelation 11:5 - 6).
The use of supernatural power directly from, and with the permission of, the true God is called a miracle. It is therefore incorrect to equate miracles with any form of perverse magic.
True miracles are performed based on God's will, not the choice of any human being or righteous angel. They are always a manifestation of his perfect love. True black magic, however, only seeks to deceive and to promote the devil's agenda of chaos and confusion, death and destruction.
The reason that black magic and the occult are condemned in the scriptures is because of their involvement with disobedient spirits. The goal of these demons is to lead humans away for obeying and worshipping the true God. They lead people into evil consequences and ultimately to physical (and possible spiritual) death. The Bible clearly condemns these types of practices (Deuteronomy 18:10 - 12).
The writings of Nostradamus, who used occult means to get information, should be avoided entirely. A believer should also avoid television shows, movies, and music with serious occult themes. Other black magic related activities to be avoided include holidays like Halloween, consulting the dead (e.g. séances), Ouija boards, psychic healings and so on.
In conclusion, there does exist a realm of fallen angels whose purpose is to attempt to take control of the universe. They seek nothing less than replacing all that is righteous with that which is evil. Demons are more than willing to deceive humans, through the promise of special knowledge and power, into indulging in black magic. All humans should completely reject such deceptions and turn to the real source of supernatural abilities in the universe. Please see our series on the definition of Christian phrases for info on other commonly used terms.