Superstition is a belief, half-belief, or practice for which there appears to be no rational substance. Those who use the term imply that they have certain knowledge or superior evidence for their own scientific, philosophical, or religious convictions. An ambiguous word, it probably cannot be used except subjectively. With this qualification in mind, superstitions may be classified roughly as religious, cultural, and personal.

Every religious system tends to accumulate superstitions as peripheral beliefs--a Christian, for example, may believe that in time of trouble he will be guided by the Bible if he opens it at random and reads the text that first strikes his eye. Often one person's religion is another one's superstition: Constantine called paganism superstition; Tacitus called Christianity a pernicious superstition; Roman Catholic veneration of relics, images, and the saints is dismissed as superstitious to many Protestants; Christians regard many Hindu practices as superstitious; and adherents of all "higher" religions may consider the Australian Aborigine's relation to his totem superstitious. Finally, all religious beliefs and practices may seem superstitious to the person without religion.

Superstitions that belong to the cultural tradition (in some cases inseparable from religious superstition) are enormous in their variety. Many persons, in nearly all times, have held, seriously or half-seriously, irrational beliefs concerning methods of warding off ill or bringing good, foretelling the future, and healing or preventing sickness or accident. A few specific folk traditions, such as belief in the evil eye or in the efficacy of amulets, have been found in most periods of history and in most parts of the world. Others may be limited to one country, region, or village, to one family, or to one social or vocational group.

Finally, people develop personal superstitions: a schoolboy writes a good examination paper with a certain pen, and from then on that pen is lucky; a horseplayer may be convinced that gray horses run well for him.

Superstition has been deeply influential in history. Even in so-called modern times, in a day when objective evidence is highly valued, there are few people who would not, if pressed, admit to cherishing secretly one or two irrational beliefs or superstitions.

Science and other kinds of knowledge
Religious Knowledge Artistic/Mystic Knowledge Scientific Knowledge
Outrageous stereotype of user Bible-thumping fundamentalist or robe-draped monk; fond of Sunday-morning radio. Crystal-hugging wearer of tie-dyed T-shirts; listens to new-age music. Geek with pocket protector and calculator; watches Discovery Channel a lot.
How one discovers knowledge From ancient texts or revelations of inspired individuals. From personal insight, or insight of others From evidence generated by observation of nature or by experimentation.
Extent to which knowledge changes through time Little. May be considerable. Considerable.
Extent to which future changes in knowledge are expected by user None. Can be expected, to the degree that the user expects personal development Considerable.
How knowledge changes through time Unchangeable except by reinterpretation by authorities, or by new inspired revelations, or by divergence of mavericks. As user changes or as user encounters ideas of others By new observations or experiments, and/or by reinterpretation of existing data.
Certainty of the user High, given sufficient faith; can be complete. High Dependent on quality and extent of evidence; should never be complete.
Assumptions That ancient texts or inspired revelation have meaning to modern or future conditions. That personal feelings and insights reflect nature. That nature has discernible, predictable, and explainable patterns of behavior.
Where users put their faith In the supernatural beings that they worship or in the authorities who interpret texts and events. In their own perceptions. In the honesty of the people reporting scientific data (the incomes of whom depend on generation of that data), and in the human ability to understand nature.
Sources of contradiction Between different religions; between different texts and/or authorities within one religion; within individual texts (as in the two accounts of human origin in the Judeo-Christian Genesis). Between users, who each draw on their own personal insights Across time, as understanding changes; between fields, which use different approaches and materials; and between individuals, who use different approaches and materials.

Excerpt from the Encyclopedia Britannica without permission.