From The Golden Bough
by Sir James George Frazer
If we analyse the principles of thought on which magic is based, they will probably be found to resolve themselves into two: first, that like produces like, or that an effect resembles its cause; and, second, that things which have once been in contact with each other continue to act on each other at a distance after the physical contact has been severed. The former principle may be called the Law of Similarity, the latter the Law of Contact or Contagion.
From the first of these principles, namely the Law of Similarity, the magician infers that he can produce any effect he desires merely by imitation it: from the second he infers that whatever he does to a material object will affect equally the person with whom the object was once in contact, whether it formed part of his body or not.
Charms based on the Law of Similarity may be called Homoeopathic or Imitative Magic. Charms based on the Law of Contact or Contagion may be called Contagious Magic. To denote the first of these branches of magic the term Homoeopathic is perhaps preferable, for the alternative term Imitative or Mimetic suggests, if it does not imply, a conscious agent who imitates, thereby limiting the scope of magic too narrowly. For the same principles which the magician applies in the practice of his art are implicitly believed by him to regulate the operations of inanimate nature; in other words, he tacitly assumes that the Laws of Similarity and Contact are of universal application and are not limited to human actions. In short, magic is a spurious system of natural law as well as a fallacious guide of conduct; it is a false science as well as an abortive art.
Regarded as a system of natural law, that is, as a statement of the rules which determine the sequence of events throughout the world, it may be called Theoretical Magic: regarded as a set of precepts which human beings observe in order to compass their ends, it may be called Practical Magic. At the same time it is to be borne in mind that the primitive magician knows magic only on its practical side; he never analyses the mental processes on which his practice is based, never reflects on the abstract principles involved in his actions. With him, as with the vast majority of men, logic is implicit, not explicit: he reasons just as he digests his food in complete ignorance of the intellectual and physiological processes which are essential to the one operation and to the other.
In short, to him magic is always an art, never a science; the very idea of science is lacking in his undeveloped mind. It is for the philosophic student to trace the train of thought which underlies the magician’s practice; to draw out the few simple threads of which the tangled skein is composed; to disengage the abstract principles from their concrete applications; in short, to discern the spurious science behind the bastard art...