Hard vs. Soft Magic
Introduction
If you've spent any time in a writing community, or watched any YouTube videos about magic or worldbuilding, you've likely come across discussions on the magic spectrum. The never-ending debate between hard and soft magic systems. While it used to get discussed in more black and white terms, most discourse I've seen more recently has definitely focused much more on it being a spectrum, with hard and fast rules at one end, and something a little more vague and conceptual at the other.
That being said, I feel like it's worth going just a little bit beyond the basic spectrum. A same magic system can be anylized upon the spectrum of hard vs. soft magic in four distinct frames of reference, divided into two contrasting pairs. First, how the system is represented in the medium, as opposed to how it is understood by the author. And second, how it is understood by the inhabitants of the world, in contrast to how the system actually works.
The Spectrum
Before we go any further, I'll quickly discuss what the spectrum itself is. If you are unfamiliar with the concept this should serve as a decent primer, but even if you are familiar, this will ensure we are all on the same page as we continue with this discussion.
Hard Magic
Hard magic exists when the rules of the system are concrete and well defined. In the hardest systems, individuals may be able to, or even be required to do complex calculations to ensure the casting of a spell will have the desired effects. More typically, however, a hard system simply means that magical ability are well known and understood, with repeatable outcomes, allowing them to be used as tools, rather than simply for thematic effect.
Soft Magic
Soft magic exists when the rules of the system are less well defined or intentionally vague. To be clear, this doesn't mean that there are no rules. Even the softest systems out there will have rules. This simply means that the rules of the system are rather open-ended, allowing for the possibility of having a variety of unpredictable or thematically appropriate outcomes, rather than repeatable and utilitarian ones. Softer magic systems typically lend themselves more to expressing the themes and tone of a story or setting.
The Spectrum Itself
The spectrum exists with hard magic at one end, and soft at the other. Most systems will exist somewhere in the middle, leaning toward one side or the other, rather than all the way at the extremes.
Representation vs. Design
The primary point of contention I personally have with much of the discussion out there on the spectrum of hard vs. soft magic, is that it tends to focus solely on how the system is presented in the medium, typically a novel or film. However, using this analysis, the 'hardness' of a system will continually change as more of the story unfolds. Every system starts as perfectly soft, as no rules are yet understood, and becomes harder as new details of how the magic works are revealed. That being said, for the purposes of this section, we will use the understanding that the reader/audience has at the end of a book, film or series when talking about the representation's placement on the spectrum.
In contrast to it's representation, the design of the system, being the author's understanding of it, is actually just as, if not more important in the classification of the system's hardness. Granted, this is not always something we have access to, especially when anylizing magic system found in works produced by others. While some modern authors (and a few of the older ones) do talk at length about their writing process, and additional details of their systems not revealed in the books, most examples of magic in works of fiction do not grant us this luxury. However, when looking at your own systems, it is very important to understand this side of the analysis. Additionally, we can often "read between the lines" to try and do some of this analysis, even when we don't necessarily have direct evidence.
Surface and Underlying
In contrast to the previous section, which draws a separation between the system within and outside of the the work itself, this section discusses the differences in how individuals who inhabit the world understand the magic vs. how it actually functions within said world.
The primary method of understanding that most inhabitants of a world will have at their disposal will be study. The individuals can interact with the magic, and observe the outcomes. In a harder system, they may be able to take those observations, and perform calculations, or logical reasoning to predict further outcomes in theory, while in softwer systems the only method of understanding may be direct observation of specific acts, or effects.
Much like in our own world, these observations will often be flawed, incomplete, or misinterpreted. If we look at the real history of scientific study, which began with philosophers contemplating the makeup of the world, the orgins of consciousness and how it all works together, we can see some interesting cases to work off of. Credited with the philisophical school of atomism, Leucippus observed that it was possible to slice a material into smaller and smaller pieces, and that there was an inevitable point at which the material could no longer be split. This lead to the formation of two concepts: atom and void. An atom was the smallest, indivisible piece of matter and void was everything around those particles. Now, today we know that while he was on the right path, this isn't how matter actually functions, and and while fundemental particles do exist, they don't exist in the way we believed, and even they can be decayed into other fundemental particles, or simply into energy.
This demonstrates, however, quite clearly that the things people believe about how the world works can both differ from reality, but also work in a functional sense, enough to be sufficient for most purposes. Numerous different philisophical, and eventually scientific, theories throughout history served the bulk of the population well enough for them to live their daily lives and even develop new technologies.
Applying this same logic to the magic system within your world, you can come to many different and interesting results, where two different cultures may be using the same underlying mechanics, but due to their different interpretations, may believe they are harnessing totally disparate forces. They may also believe limitations exist where they don't, or not be aware of some limitations which do exist.
At the end of the day, however, especially if you are going to be utilizing groups to different interpretations of the magic in your worlds, you should ensure that you do actually have a solid understanding of the underlying system, to ensure internal consistency. If you don't have a solid grasp on that underlying system, it can be very easy to accidentally create inconsistencies within the system, such that those different groups really are opperating under different rules, even when you didn't mean for them to be.
Final Thoughts
Considering the different frames of reference presented in this article can be helpful in developing a magic system, but first and foremost it allows you much greater control over the the experience of your audience, however they are interacting with your work.