According to the Bible, there are only TWO sources of supernatural power that humans can access. The first is God, who allows those such as righteous angels or humans to circumvent natural laws ONLY with His permission and based on His will. The second is Satan and his demons (which those who practice black magic attempt to tap into) whom the Eternal (for a time and 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 great deception by the devil, who wants to deceive humans into accepting that black magic (any supernatural ability not from God) is not really all that bad and, in fact, can 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.
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 other-worldly 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 black magic. True miracles are performed based on the HIS 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. These demons are spiritual guides to ways that are contrary to God's. 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. seances), 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 using any means possible. They seek nothing less than replacing all that God stands for with 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.