Some works of Speculative Fiction
use magic, Sufficiently Advanced Technology,
or Applied Phlebotinum
in highly mystical ways; they can do whatever the author requires
to make the story interesting. Others take a very different route, making their magic
or high technology
subject to strict and well-defined in-universe rules. But under what criteria should an author choose one approach over the other?
According to Brandon Sanderson
, using this choice effectively is closely related to a second factor: whether or not the story allows the protagonists to use the magic to resolve problems in the plot they find themselves a part of. He formalized it as Sanderson's First Law
An author's ability to solve conflict with magic is DIRECTLY PROPORTIONAL to how well the reader understands said magic.
In other words, if the protagonists are going to use magic to solve their problems, the reader has to understand ahead of time
that this is something they are capable of doing. If not, the reader will feel that the author is simply making stuff up as he goes along.
In stories where the rules of magic are not explained, it is useful for flavor and description, and to give the story a sense of ordinary characters
being caught up in part of something much bigger than themselves, but they will rarely be able to actually magic their way out of trouble if the story is well-written.
Note that this only applies to resolving problems, according to Sanderson. Magic can always
be used to create trouble for our heroes!
- Brandon Sanderson has a distinct preference for the Rule Magic side of things. He's stated that to him, "obviously magic has to have rules," and it shows in his writing. Each world has its own set of well-defined rules, and a major theme in most of his works is the characters figuring out how to do new and interesting things with magic within those rules in order to further the plot. In fact, discovering a highly significant, foreshadowed-but-overlooked aspect to the rules of magic was a major element leading directly to the climax of Elantris.
- The Lord of the Rings is on the other end of the scale. Despite the party traveling with one of the most powerful wizards in the world, the focus is on the non-magical characters, and it shows.
- When Gandalf tries to open the way to the Mines of Moria, he wastes time using all manner of unlocking and opening spells, before finally figuring out that the lock is not a spell, but a riddle. (The Movie takes it one step further: Gandalf never does figure that out; one of the hobbits does.)
- When Gandalf tries to use his magic to confront the Balrog, the party ends up losing him.
- And at the very end, Frodo finally tries to solve his own problems by claiming the ring, which the reader understands would be a Very Bad Thing, and the only thing that ends up saving the day is Gollum's intervention.
- Harry Potter plays with this: new powers and magics are frequently made up as necessary, but after they show up in-story, they're given some sort of rule and used consistently from there on. It works surprisingly well.
- Violating Sanderson's First Law is the reason why The Sword of Truth is frequently accused of Deus ex Machina. The audience is frequently told that magic works based on a highly rational and scientific set of rules, and there's a fair amount of Magi Babble scattered throughout the books to assure us that the characters understand exactly how magic works, but the readers never get any sort of detailed explanation. So when wizards (particularly Richard) come up with some spell to save the day at the climax of one of the books, (which happens multiple times,) it inevitably comes across as an Ass Pull on the part of the author.
- In the Myth Adventures novels, readers see Skeeve taking lessons in magic and picking up new techniques, so it's readily apparent what his abilities and limitations are. He's usually free to use these powers to deal with his problems, and when that's not an option, the reasons why he can't (e.g. scarcity of force lines) are also explained.
- In the Lord Darcy stories, Master Sean's discourses on magical theory make it clear to readers why he can identify and analyze some clues to a mystery, but not others. The information he obtains via magical means is always of value, although it's still left up to Lord Darcy's intellect to deduce what it proves about the crime. Magical effects not related to forensics may or may not be explained, but ones that aren't (e.g. how Master Sean's carpetbag returns to him) are usually played for comedy; if they're a direct element of the crime (e.g. the Tarnhelm effect), they'll be explained as well.