Notes on Strange Fiction: Magic
Ted Chiang has pointed to a key distinction between science and magic: the former is reproducable industrially, on a mass scale, while the latter is not. Generally, in fact, magic is the preserve of a select elite of exceptional individuals, so much so that at it may become a signifier of their selection by the ultimate magic of the divine, a signifier of their destiny. Unpacking this and looking across the field of fiction though, we can say that human application of magic is located on a spectrum of methods of production that runs thus:
facility (gift) | art (talent)| craft (skill) | technique (process)
The rarity of magic is a product of where it is placed on this spectrum by the fiction it is found in. Magic may be presented as a facility, a gift that only the exceptional have; it may be presented as an art that only the exceptional will have a talent for, but that is learned almost as much as it is innate; it may be presented as a craft, a skill that does come naturally to some, but that is more learned than innate and therefore open to use by anyone; it may be presented as a technique, a process which can be reproduced industrially because it is abstracted to mechanistic procedures.
The last presentation of magic is rare, used largely as a deliberate subversion of conventions (as critique or satire), and it this that places magic in distinction to science, the system of abstraction by which craft is transformed to technique, process identified in skill and therefore rendered reproducable, open to industrialisation. What marks DUNE out as utilising magic rather than science is that the Guild navigators' manipulation of time and space is a craft (signified as such by the term guild in its referencing of pre-industrial skilled-trade organisations.)
The division between craft and technique is however blurred when the non-reproducable nature of magic is explicated (or implicated) as a ramification of it being a semiotic phenomenon. Which is to say, the activity may be an emergent feature of language and consciousness, requiring the four key abilities of an agent dealing with a world of signs: reception; perception; conception; inception. For a machine to be an agent it must be able to receive stimuli, perceive those stimuli as signifiers, conceive what is signified (i.e. process sensation into thought), and initiate action (i.e. act on thought rather than automatic response). Magic can be presented in these terms, as a semiotic interaction with reality, a reading of its language and a (re)writing of its text through the application of that language; it is a hacking of reality. Here magic is reproducable (this is why it is a craft, a skill) but for it to be mechanically reproduced requires that machine to replicate the semiotic agency of a sentient being who knows the code.
In Asimov's "Let There Be Light" this is essentially what is achieved by the end-product of AI technological development, but in general a more conservative outlook pervades the field, one where such semiotic agency is considered limited to human beings (or entities anthropomorphised with sentience). Ironically, that magic is not mass-reproducable might be taken to indicate a less fanciful worldview, a skepticism about the possibility of machine sentience. Alternatively, it may indicate an anti-materialist notion that semiotic agency is the product of some sort of metaphysical enspiriting that human beings have and machines do not -- a soul. Either way, note that in the TV series ANDROMEDA for a ship to travel through the slipstream (FTL) requires a human pilot because even machines with a fully-sentient AI are not capable of navigating this (magical) location/state. Note that jaunting, in Bester's THE STARS MY DESTINATION is a skill (craft) that pretty much everyone can learn but that jaunting through space is a talent (art) that only Gully Foyle has achieved. Note that at the end of the book he considers teaching this ability to humanity (transforming the talent to a skill, distributing it as he does PyrE) but has not yet begun this task. Note that either way jaunting is an essentially human capacity, not open to mechanisation.
The characterisation of magic as a semiotic skill has, in fact, resulted in a back-reading whereby it becomes symbolic of semiotic skill itself -- a metonym of the power of language, of consciousness, of "spirit". It is the extent to which the last of these is profoundly resonant as figurative metaphor and profoundly religious as literal concept that renders magic both pervasive in SCIENCE FICTION and reviled as FANTASY.
Note that the magic of Bester's jaunting is associated with the Promethean fire of PyrE, an enervated and explosive substance triggered by thought (i.e. magic), a blatant concretion of the metaphor of semiosis-as-power.