Another way of thinking about this is ordinal vs numeric. Both can be used to compare things, but with one you get much more detail to say how they relate, whereas with the other you are simply told this is the ranking.

The part of this that becomes more interesting to me is in the readers acceptance of conflicting ideas, where the difference between the two systems break down. For example, you have something that is infinitely durable and is shown to be that consistently. It then at some point gets damaged. So how was it infinitely durable? I think the reader inherently understands that the “infinite” part was a misnomer without further explanation. We accept this, regardless of the magic system, because we both hold a loose idea of the concept of infinity in our heads while also knowing that there is always something bigger/stronger/faster/better out there. Because what’s infinity, really? You can always think of a larger number. This concept can be expanded to include all edge cases: e.g., end points and equal but opposite forces. To put this into practice, what happens in a hard magic system when you reach the end of the world and decide to take the next step? Same as in a soft magic system. It’s completely up to the authors whim.

Since there is quite a bit of wiggle room then, perhaps two scales are needed to describe a book. One for the system and one for how frequently the author breaks/abuses/introduces something “new” about it that was unknown previously. I think that last one is something that Brandon Sanderson is a master of. He consistently introduces new concepts to what feels like fully fleshed out magic systems without making the reader feel like it came out of nowhere. I would still describe this as a hard magic system, as the concepts are explained in detail and follow a logic that makes sense. However, the way it’s introduced is definitely meant to incite a “sense of wonder” and often feels a bit deus ex machina.

By the way, I’ve greatly enjoyed your books thus far and am looking forward to the next one :).

Hah, I never saw Warlock, but that sounds fun!

I’m glad you found this all useful! And your book looks pretty cool, picked it up on Kindle Unlimited!

Oh cool ⏤ I’d be really interested to hear what you think.

https://www.amazon.com/Effra-Novel-Greg-Roughan-ebook/dp/B006RRFPSC#

I would argue that emergence versus Platonic is not quite the easiest way of getting at the idea you seem to be talking about.

Also, I think that your emergence could be argued to be only a restricted number of ideas from a general Platonic approach. This might be why you stated you found the transition between emergent and Platonic to be gradual.

An idea of how atomic a magic is, or how divisible/reducible it is, seems to me to fit your examples better.
I also would include the idea being self referencing as a type of divisibility as well (this handles meta structures).
This line of reasoning is related to Formal Language Theory https://en.wikipedia.org/wiki/Formal_grammar
Like a regular grammar (more reducible/less atomic) versus a context free grammar (less reducible/more atomic)
There are some interesting notions in Language Theory that would enable this idea to be broken down further (and potentially even quantified)

So a magic where someone could only do fire magic by increasing heat is not reducible to sub-powers, concepts, or phenomenons. It is still a flexible power, in that you could cool a space if you could control heat well enough (think how modern air conditioning produces more heat than it removes, but in a limited area can still cools).

Platonic forms of elements for magic generally group together a wide array of sub powers and concepts under the label of those things associated with the element. It also depends on the grouping for what is associated with an individual concept, air magic can get either emotionally flighty things associate with it or aloofness which lead to different powers.

True name systems tend to be a spoken language, and as language can support a wide variety of concepts – including self referencing – lead to drastically more divisibility. Which would make it higher on the scale than merely Platonic forms of 4 elements.

This also should address your issues with Sygaldry that as runes are a written language, even if the grammar may be restricted, it is not atomic and is therefore reducible. Since it is a written language, and is portrayed as having defined effects, it is more atomic than a spoken language between two humans which can have ambiguity (non obvious intent) but it is very divisible

Getting away from the specific examples you mentioned, a parallel that can be drawn is notes in music.
You can make music with a series of only two notes (a sound and not a sound). This is not very reducible at all.

You can make music with four different instruments able to play two different notes. This is somewhat reducible.

You can make music with one instrument able to play 8 different notes. This is reasonably reducible.

So a descriptor based of complexity of reduciblity may fit your descriptions better

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Looking forward to the next book, and if your idea of emergence/Platonic helps you write, more power to you.