[This is part of a long series looking at atheism and Wicca.]
Any procedure for changing an initial situation (the start) into a desired situation (the goal) can be tested for its effectiveness. As used here, effectiveness is a matter of degree, so that procedures can be more or less effective. The simplest way to measure the effectiveness of a procedure is to divide the number of successful trials by the total number of trials.
To help keep things clear when analyzing magic, it will be useful to introduce the following precise terms of art: A procedure is tested in a group of people if its effectiveness has been measured within that group and it is untested otherwise. A procedure has some reliability if its known effectiveness is better than chance and has no reliablity otherwise. A procedure is sound in a group of people if it is among the most reliable procedures known within that group and it is less than sound or unsound otherwise. Obviously, every sound procedure has been tested. Although every sound procedure has some reliability, the best we can do in many cases may not be much better than chance. Although sound procedures must have some reliability, they need not have much reliability. The technical expertise of any group is the collection of all sound procedures known within that group.
The term spell is used here for any procedure that is presented as magical in any Wiccan text. Wiccan texts offer elaborate catalogs of spells. The set of surveyed spells includes the spells presented in Farrar & Farrar (1981); Bucklands (1986); Cunningham (2004); Sabin (2011). The texts that present the surveyed spells do not present any data to measure their effectiveness; all the surveyed spells are presented as untested. And I am not aware of any tests of any surveyed spells.
For those spells that are untested, if Wiccans or others cannot provide evidence for reliability that meets the same epistemic standards as the evidence for the reliability of our technologies (which Wiccans use too), then it is cognitively wrong for Wiccans or others to assert that the spells have any positive reliability. And if they cannot provide evidence that meets the same standards as the evidence for the reliability of our best technologies, then it is cognitively wrong for Wiccans or others to assert that the spells are sound.
All surveyed spells compete with (or are offered as alternatives to) procedures which have known positive reliabilities or which are sound. All surveyed spells make use of operations and objects whose technical properties and relations are already well-understood. Since the well-understood technical properties and relations of those operations and objects do not reliably produce any of the effects listed in the surveyed spells, it is reasonable to conclude that all surveyed spells have zero reliability. Of course, the fact that this conclusion is reasonable does not entail that it is true – it must be tested.
But the fact that it is reasonable to say that the surveyed spells have no reliability does entail that nobody has any reason to test those spells. Of course, Wiccans may test them if they like; but they cannot complain that others are obligated to test them in order to deny their reliability or to deny their soundness. Skeptics are under no obligation to test the spells in order to make the entirely rational claim that they have no reliability and no soundness. Even without testing them, it is rational to deny that they have those features. If Wiccans want others to test the spells,then it is up to the Wiccans to give reasons.
If you use a car, a cell phone, a computer, or any product of advanced technical expertise, then you have every reason to say that the surveyed spells have no reliability. And you contradict your own behavior if you insist otherwise without providing evidence which meets the same epistemic standards as the evidence used to make the technologies you use. Here actions speak louder than words: if you use a cell phone, then you don’t really believe that spells work. On the contrary, you place your faith in science and technology. The purpose of magic is purely psychological: to induce the illusion of control.
Buckland, R. (1986) Complete Book of Witch Craft. Second Edition Revised and Expanded. St. Paul, MI: Llewellyn Publications.
Cunningham, S. (2004) Wicca: A Guide for the Solitary Practitioner. St. Paul, MI: Llewellyn Publications.
Farrar, J. & Farrar, S. (1981) A Witches Bible. Blaine, WA: Phoenix Publishing.
Sabin, T. (2011) Wicca for Beginners: Fundamentals of Philosophy and Practice. Woodbury, MI: Llewellyn Publications.