Roger Bacon, an English Franciscan friar, scientist, and philosopher, accepted what he termed the "natural magic" that occurred within mathematical and physical areas of experimentation, but he was resolutely against the use of incantations, the invocation of spirits, and the casting of spells. In his opinion, magicians were charlatans, reciting magical formulas even though they knew the effects they created were but the products of natural phenomena.
Bacon recognized that there were mysterious forces that appeared to be magical, such as those that moved the stars and the planets; but he argued that all knowledge that existed on Earth depended upon the power of mathematics. The friar also admitted the difficulties in discerning between the natural magic of science and the black arts. He was convinced, though, that natural magic was good and black magic was evil.
This thirteenth-century alchemist seemed to have powers of prediction when he told his contemporaries that physics, not magic, would produce huge vessels that would be able to navigate the oceans and rivers without sails or oars, cars without horses that would be able to move at tremendous speed, flying machines that would soar across the skies guided by a single man seated at centrally located controls, submarine machines that could dive to the bottom of the sea without danger to its crew, and great bridges without pillars that could span rivers. Bacon has been credited with dozens of inventions, such as the telescope, eye glasses, gunpowder—all derived through his science, rather than his magic.
In his medical practice, Bacon worked with certain alchemical formulas prized by specially gifted scientists since ancient times that could create a mysterious liquid known to prolong human life. He also employed the alchemical and homeopathic principles that "like produces like," that is, if one wishes to prolong one's life, he or she should eat the flesh of creatures that are long-lived, such as various reptiles.
Steadfastly arguing that all human knowledge depends upon a study of mathematics, Bacon insisted that the noblest expression of mathematics is astrology. At each person's birth the heavenly energies determine powerful physical, mental, and emotional factors that strongly affect that individual's destiny. The stars do not decide one's fate, Bacon conceded, for humans did have free will as a divine gift, but the celestial movements did most certainly dispose one toward one's fate. Therefore, he concluded, astrology should be utilized as a powerful tool in medicine, alchemy, and predicting the future of individuals and nations.
Friar Bacon was well aware that the church did not share his enthusiasm for astrology, but he argued that the Bible itself is the basic source of astrological knowledge and that a careful study of astrology would ultimately prove the claims of theology. Fellow clerics who opposed such a study, Bacon said, were merely ignorant.
In spite of such statements that seemed tinged with heresy, Bacon's religious views were essentially orthodox, and he sincerely believed that his studies would only serve to advance the power and the prestige of the church. He also drew upon scripture when he acknowledged the enormous power of the spoken word ("In the beginning was the Word, and the Word was with God, and the Word was God." John 1:1). Bacon stated that all miracles at the beginning of the world were the result of God's word. Therefore, when humans spoke with concentration and the proper intention and desire, their very words could accomplish powerful effects upon the self, upon others, and upon material things.
In his great determination to produce a work that would unify all learning, wisdom, and faith, Friar Bacon wrote Opus Majus (1268). Despite the fact that Bacon continued to attack superstition and reject the black arts, he remains widely known as a magician, rather than an early experimental scientist.