In the last post, I presented a library of sourceworks to serve as a foundation for an understanding of magic that could apply to the Middle Sea and Sundaland settings, as well as future incarnations of my Deindustrial Future setting. Partly, I wanted to clearly differentiate my approach from that of another occultist and gaming blogger, whose series on "Real Magick in RPGs"—yes, that is the spelling he uses for the word—is worth reading, but presents the topic from a very partisan perspective (much as that author's politics! ZING!) which can be quite misleading for those who take it literally and without a wider view. I won't link it because the author is kind of a jerk, but it's easy enough to Google that series up.
To figure out how magic works, we first need to know what magic is. This is an incredibly difficult question to answer definitively, and the more so as it is examined more closely. For my purposes, I will assume that "magic" is what historical magicians or magician-like people thought that they were doing. This isn't a hard and fast definition at all since it requires us to look at what "magicians" do in day to day life, and that is simply not possible from our vantage point here in the early 21st century. Even as recent an era as the 1980s remains somewhat opaque since our main source work on practicing magicians from that period has a number of methodological problems.
To our benefit, a number of magicians wrote down, in outline at least, descriptions of how they pursued their practices. While there is some obscurantism in many of these works, a lot of the codes have also been written down and others have been broken.
For simplicity, I am going to focus on the (very) Late Antique, Early Modern, and Modern eras in Europe, say from the 7th century or so on through into the 18th or 19th, and even the 20th and 21st to a degree.
Earliest in our period and location, we find the Greek Magical Papyri and the Demotic Magical Papyri (PGM/PDM). These are a collection of various papyrus manuscripts that record in quite close detail the practices of magicians of Antiquity, with some of the practices perhaps originating in prehistory. We do not need to examine this in detail, however, and will only note in passing that there is a clear line of transmission from these manuscripts into later European magical works. If you are interested in pursuing this further, I'd suggest Betz, Hans Dieter - The Greek Magical Papyri in Translation, Skinner, Dr. Stephen - Techniques of Graeco-Egyptian Magic, and Smith, Morton - Jesus the Magician. Those would get you started.
Another source text, roughly contemporaneous with the PGM/PDM, is Sefer HaRazim, a collection of Jewish magical practices involved with conjuring the spirits of the dead, appeasing them, exorcising them, and so forth. Our interest here is mainly to show that there is a melting pot of practices in the eastern Mediterranean region, from Egypt to Greece, that resulted in a basic pattern of what would become the central magical practices of Europe for centuries to come.
Because of the way that books were circulated in Europe prior to the introduction of the printing press, there are lines of tradition that we can consider, rather than necessarily individual titles. So, for example, there is the "Solomonic" line of texts, which include books that find their ultimate origin in the Byzantine magical text known variously as Hygromanteia (Ὑγρομαντεία), Solomonikê (Σολομωνική), or The Magical Treatise of Solomon, among other names. However, these books vary greatly in the exact text, with some leaving parts out, adding new parts, or rearranging sections. The Solomonic books make up most of the magical texts that exist, but there other others such as Picatrix, which finds its origin in an Arabian text titled Ghayat al-Hakim ("Goal of the Wise"), translated initially into Latin then into other languages; the similarly-named but different traditions of the Cyprianus, or Swedish Svarteboken, which lead to the Braucherei tradition, also known as Pennsylvania Hex magic, among others, and the books of magic that attribute themselves to St. Cyprian of Antioch, the "Necromancer Saint"; the Faustian tradition, which consists of a number of texts that seem to be based on the legend or play; variations of the Three Books of Occult Philosophy by Henry Cornelius Agrippa von Nettesheim; and a few others. Some of these are among the strands of tradition that form the various African Traditional Religions as practiced in the New World. More recent years have brought a few further texts such as the infamous Necronomicon, widely available in a mass market edition from Avon Books; The Voudon Gnostic Workbook by Michael Bertiaux and related books; the various works of "Chaos Magick" theorists and practitioners such as Peter Carroll, Phil Hine, and others; various texts on "witchcraft" of varying quality, some connected with the religion known as Wicca and many not; the practice known as "Huna" developed by Max Freedom Long; the Thelemic and other texts associated with Thelema, many by Aleister Crowley, though a lot of more obscure books written by others; the Thelemic works have their origin in a strand of tradition known as the Golden Dawn, which owes at least a portion of its practices to the works of Éliphas Lévi; the rediscovery of Dr. John Dee's 16th and early 17th century magical manuscripts in the 19th century was another influence on the Golden Dawn and Thelema, but that collection also forms a tradition of its own. In addition, there are folk magical practices, some recorded relatively faithfully—such as in the Rev. Robert Kirk's manuscript The Secret Commonwealth, published in an abridged form in the 19th century, then in a more complete form in the 20th—while others can only be seen dimly from the point of view of people antagonistic to them such as the records of witch and werewolf trials mainly in the 16th and 17th centuries. And this really isn't a complete catalog.
This anarchic mass of textual data is difficult to assimilate. However, we can point out a few common practices throughout. First, there is "Spirit Magic", in which various "spirits"—whatever we may come to mean by this—are interacted with in various ways. This can be through divination of various sorts, the perceptions of a sensitive "medium", or even full-on possession, as with "channeling" or the practices of various African Traditional Religions. This includes practices which purport to direct or determine the influence of "astral energies"—sometimes called Astral Magic—and the practices known as "theurgy" which are designed to align the practitioner with some spiritual power. Further, the practices known as Natural Magic, which intend to direct the powers of natural objects such as herbs and stones, or even the more sophisticated methods of the Alchemists, can also be seen as directing or assessing the spirits of those objects. Some forms of Natural Magic (and the same is true of Astral Magic) intend to take advantage of psychological processes, such as a similarity of appearance, but others rely on real or apparent physical properties.
Second, there is divination that is not apparently related to spirits. This is a difficult distinction to make, though, and only becomes more so as the idea of spirits is examined more deeply. However, the idea of viewing locations at a distance, which some now call "remote viewing", has an ancient pedigree. Other forms include "oneiromancy", or the interpretation of dreams, scrying, inducing various sorts of altered states of consciousness, and various forms of sortilege, or casting and otherwise manipulating lots, cards, sticks, dice, or whatever, among other things. This is a major topic of its own.
Thirdly, we can identify what we might call "Psychic Magic", or "magic" that is related to altered states of consciousness. This crosses over to "Spirit Magic" and "Divination" considerably, but includes other practices such as the "berserk" state, self-hypnosis, and induction of hypnotic states in others. There are other examples as well.
Finally, there is the practice of "Illusion". This is exactly the sort of thing that modern stage magicians do. The thing is, it turns out that a lot of magical practices occur on a purely internal, invisible level. Sometimes, that internal, invisible matter needs to be dramatized, and so we find practitioners engaging in allegedly "fraudulent" (though, notably, the only perspective from which there is fraud is from a naïve, predetermined, materialist one; other perspectives will emphasize the efficacy rather than any theoretical metaphysics allegedly underlying the practices), but nonetheless effective to some degree, practices like "psychic surgery" or the like.
And here is a point for a quick digression. Everyone has a metaphysics, whether they understand it consciously or not. This is the model of how the universe works that allows a person to comprehend the things that happen around them. There is no known way to prove one metaphysical model over another, except perhaps by comparing effectiveness—and that only shows a relative effectiveness by whatever definition of "effective" is employed, not any final determination of objective validity. But this is another essay entirely. For our purposes, let's just agree that a non-materialistic model of the universe is at least possible, and so the universe of the magician is not a prima facie impossibility.
I may have missed some other practices, but these seem like the central four to me. This model offers a primary place for "spirits", which leads us to the next question: what, exactly, is a "spirit"? That is a good question for next time. Also, at some point I need to get more explicit about the gaming connection. I'll get there.