What is Magic in your Setting?

[Lemmy]

Hello, fellow playgrounders!

Today I have a question for you all:

What is "magic" in your setting?

Actual magic, I mean.

I know it's common to use the term "magical system" to refer to any kind of fantastical powers in a setting... But what do the inhabitants of your setting call "magic" in-character?

e.g.: Superman is clearly able to defy the laws of physics as we know, but his powers aren't considered magical in the DC world (in D&D terms, they're just really powerful Extraordinary abilities).

Similarly... In the setting and story I'm currently working on, there are 4 types of "magic", 3 of which aren't considered actual magic in-story, because they are explained by the physics of the world (it's just that they use physical forces, elements and phenomena that don't exist in our world).

In this setting, the world "magic" is reserved for one specific phenomenon, which can be replicated (though not perfectly), but can't be explained and seems to break the known laws of physics (including the new ones that I created to explain other "magical" phenomena, including creatures breaking the square-cube law and things like conservation of momentum not working as they do IRL).

So... With that in mind...

What is magic in your setting? And why is it called magic?

Bonus: Are there other impossible phenomena (by real world standards) that they do not consider magical at all? Do these phenomena get any explanation for how they work?

[Millstone85]

I typically picture magic as an "energy lifeform" that, for whatever reason, lets itself be channeled by us meat bags. It isn't necessarily a single unified organism but can be a whole ecosystem of spirits with various degrees of sapience.

Magic can coexist with, yet remain distinct from, various types of unobtainium and exotic particles. These allow incredible technological progress, including sapient and/or self-replicating robots, but otherwise seem to remain firmly under the concept of "the inanimate", same as existing elements and radiations.

Magic can also coexist with abilities that are explained as being part of a creature's (often an alien or mutant's) fictional biology.

If a machine runs on the blood of Cthulhu or contains a crystal from the shadow realm, we are now speaking magitek. If regular humans have a soul or life energy, with mutants just using it better, that's another blurred line.

[NichG]

Lots of settings, lots of answers...

Generally though, the essential things which make something 'magic' to me rather than something else are:

- It's more reasonably understood through a psychological or at least a human-scale perspective than through underlying elementary laws giving rise to emergent phenomena. That is to say, things like 'it does what you intend' or 'it cares about abstractcategories like sentient vs unsentient or animal vs plant or lie vs truth or justified vs unjustified' make a power system feel more magical to me. Magic means to some extent finding a way to make the world care about the sorts of concepts that a person cares about (or finding that this was in fact the rule of the world), as opposed to finding that the things upon which the world is built don't care about those high concepts at all.

- It represents some kind of personal relationship to power, rather than an indirect or collective relationship to power. In a scientific setting, someone may use knowledge to make something possible that wasn't possible before, but that knowledge will lead to something that is not necessarily the inventor's personal relationship with power - it works the same for everyone once its been discovered. That's sort of a basic principle of science, that you can basically do disentangled experiments about reality and the results stay the same if someone else did that same experiment somewhere else, controlling for those things that matter. Something that breaks this rule feels more magic-like - this spell only works for one caster because it's based on their own personal metaphor for reality, and transferring it to someone else without transferring the philosophy as a whole doesn't work. Or, this caster can work magic because of their own personal relationship with the avatars of the forces of nature - if you don't go and dance with the fire elementals, fire spells just won't work for you.

Easy generalization, too much distance between the practitioner and the practice ('magic' that can't at all just be done by a person but which could only be done through artifacts would be more like tech; having both personal expression and machine expression though is 'fine'), things which are too impersonal or don't make contact with the conceptual all make something feel more like science or tech or biology.

That doesn't mean that magic has to fundamentally be incoherent or not make sense. It just means that the 'sense' it makes is more like a psychologist understanding how people work than a physicist modeling an electron gas. And the way in which it can be coherent and make sense for a universe to allow such a force is often something of the form 'at some level, this universe is just some vast being's dream or thoughts' or 'everything in this universe has a low-level sentience' or 'this universe is fundamentally a conversation, and things like matter are just the consequence of what was said and are not the language itself' or other such ideas. Or even just 'eons ago, a hyperadvanced civilization made AI-driven nanites that have since infused everything, and magic is just these nanites occasionally responding to the commands of people when someone gets close enough to mental constructs used by those ancients', which is a very tech way of saying something that in the end could easily have the feel of magic (even if getting into the actual nanite level would flip it over in feel immediately).

So basically its almost always the case that there is some kind of 'mind' underlying magic, in magic systems I make.

[Pauly]

I'm working on a homebrew urban fantasy system currently.

'Magic' is a subset of supernatural, belonging to witches. Supernatural is defined as being outside of the natural laws. Therefore trying to use highschool physics to Macgyver a solution just doesn't work.

Vampires are affected by sunlight and only sunlight. Making a lamp that created light which has the exact same properties as sunlight will not affect vampires. Garlic bulbs affect vampires but making a garlic paste and putting it in a grenade doesn't work. If natural laws worked on the supernatural then the previous two examples would work. But since the supernatural are outside of nature they don't work.
It also goes the other way. If a witch casts a spell to cause something to burn, as soon as the spell ends the fire ends and the item will be at the temperature it was before the witch cast her spell. An object affected by a supernatural power will revert to its original temperature/ momentum/ etc immediately when the supernatural effect ends.

[Satinavian]

I often play in official settings of established systems.

In TDE Magic is when the seventh element (representing magical energy) is manipulated to achieve anything. That means that anything powered by the divine, including anything priests do is not considered to be magical at all even if it looks as supernatural.

In my Splittermond games, Magic is primarily any and all spells and rituals. And then natural abilities and occurrences that seem similar enough to those. However that means the less people know about something, the less certain they are whether it should count as magic or not and it is often debatable in game as well. There is no really clear delineation. Is it magical that a Roc can fly ? Who knows ? But honestly, people rarely care about whether something is magical or not. It is what it is. And as everyone can learn spells and stuff, it is not seen as unnatural either.
The system and setting has three established distinct supernatural power sources and there is theory behind stuff. But the word "Magic" could be applied to effects from any of them but would not be applied to every effect.


In my current PF game that never came up. But i probably won't do that whole "psionics is not magic" thing. Everything that uses something like spellslots or SLAs or is a magical item will be magic. Kineticists will also use magic. But i don't have a proper "magic system" that makes sense for that campaign and can't be bothered to try and build one.

[Quertus]

As a programmer, of course I love, “magic is just direct calls to the underlying system running the simulation”. But, really, I rarely make it anything more complex than, “a form of energy that responds to Will (see system/ setting details for whether that’s ‘trained will’ (Wizards), or some other qualifier), but otherwise interacts with Matter in only a few very specific ways (creating localized cube-cube law, allowing certain Supernatural phenomenon to occur, whatever)”. So, The Force is everywhere, but if you don’t have lots of space bugs in you, you can’t make it do much if anything.

[KorvinStarmast]

.

What is magic in your setting? And why is it called magic?

Magic is the term used in English, that is why it is called magic, since we play using the English language.
What is magic in my version of World of Greyhawk?

The practice of magic is varying ways to tap into the fundamental Chaos of Reality and thus create some kind of effect, and to control it. Wild magic effects, for example, demonstrate the variability and danger of magic, as do other overlaps of magical powers.

How one taps into this Chaos varies: could be due to an item, help from a deity or fiend, following previously discovered formulae, trial and error, discovery, etc.

Magic is generally held as dangerous. Tampering with it was the cause of the Rain of Colorless fire, and as a result the dragon clans began to hunt down and kill wizards and artificers. Those are the two kinds of people who were tampering with chaos and caused that catastrophe which turned their massive prairie/preserve (where herd animals like on the Great Plains of North America) once roamed which provided massive sustenance to various dragon clans.
It is now The Sea of Dust.

As a result, wizards and artificers are hard to find. They exist, but are rare, and tend to keep their true nature hidden or not well advertised.

In 5e, mechanically, that means that most of the "wizard" or "mage" NPCs are mechanically sorcerers (I swap the INT and CHA Scores) and dont use spell books. A few do.

Warlocks are a lot more common in terms of Arcane Casters, and there are sorceors around: but they tend to be viewed with suspicion by most people.

Divine magic is usually seen as more benign, but cults are a problem that are rooted out where they can be.

PCs who use magic openly get differing reactions. Sometimes they are shunned, other times welcomed, depends on what they are doing.

Dragons (particularly the blue, white, copper, plaid and green dragons) are still hunting down and eliminating artificers where they get news of them.

There is a PC artificer (now retired the player had a scheduling conflict) who has been given a reprieve by the plaid dragon who oversees that region, due to services rendered in rescuing that dragon's niece and taking out the Kraken/Cult around the Styes. (Last adventure in that module). The Styes, now no longer under the Kraken's nor the Aboleth's influence, is cleaning up its act and restoring itself to its former status as Star City.

Keledek (the LE mage from Salt Marsh) and a Transmuter (who is Ingo's colleague from the Great Kingdom) were both eaten by the dragon turtle who lives near Salt Marsh (for different reasons)during the campaign. Keledek is from Ket, and had been accepted by the town council as a scholar and the keeper of the local library.
He'd been doing some research into the Tower of Xenopus, which is how he ended up interacting with the Party many levels ago ... but he was using them for his own evil ends. (Didn't work out for him). He was 317 days into completing a permanent Teleportation Circle back to Ket up in his tower (casting it once per day) when he met his demise.

Magic:
It is powerful, it is dangerous, and it is useful (or can be). Handle with care.

[Anonymouswizard]

It's all magic. Magic is the term for all such abilities, as well as the common term for what wizards do (as opposed to divine 'miracles'). Scholarly wizards and the like use 'spellweaving', but your average person in the street or fields doesn't care.

Lovely magic is split into four types:

• Spellweaving/Arcane
• Miracles/Divine
• Primal Channelling
• Ki Manipulation (includes psionics)

The first is based on exploiting flaws in the world, the other three are 'legitinate', but not every practitioner will use just one. Bards and sorcerers pretty much always just mix the types together and go with whatever works. At the end of the day it doesn't matter beyond characters generally not having a great understanding of other magic types and the occasional plot point based on the fact these are different. The exact differences are kept relatively loose to help with storytelling.

TL;DR: opposite to the intent of the thread I make magic the overall term and subdivide, rather than going 'this is actually magic's.

[Vahnavoi]

Hello, fellow playgrounders!

Today I have a question for you all:

What is "magic" in your setting?

Actual magic, I mean.

I know it's common to use the term "magical system" to refer to any kind of fantastical powers in a setting... But what do the inhabitants of your setting call "magic" in-character?

From the Free Dictionary: mag·ic (măj′ĭk)
n.
1.
a. The art or practice of using charms, spells, or rituals to attempt to produce supernatural effects or control events in nature.
b. The charms, spells, and rituals so used.
2. The exercise of sleight of hand or conjuring, as in making something seem to disappear, for entertainment.
3. A mysterious quality of enchantment: "For me the names of those men breathed the magic of the past" (Max Beerbohm).
adj.
1. Of, relating to, or invoking the supernatural: "stubborn unlaid ghost / That breaks his magic chains at curfew time" (John Milton).
2. Possessing distinctive qualities that produce unaccountable or baffling effects.
tr.v. mag·icked, mag·ick·ing, mag·ics
1. To produce, alter, or cause by or as if by magic: "Intelligent warm-hearted Gertrude had magicked him into happiness" (Iris Murdoch).
2. To cause to disappear by or as if by magic. Used with away: His shoes had been magicked away in the night.

That's what the word means. That is how people use it my settings. Notice that "using charms, spells or rituals to attempt to [. . .] control events in nature" is not mutually exclusive with technology. It is technology. Magic is, first and foremost, a thing humans do, and people have done it and continue to do it regardless of whether it works. The split between magic and technology, both in and out of setting, is arbitrary and idiomatic. A good chunk of occultists would look at a smartphone and consider it a magical device: you spell a command using millenia old symbols that correspond to sounds made by human mouth, to control a black box machine that then sends a signal forward as a wave of invisible energy, to be caught by another black box machine and transformed into effective work elsewhere. If your counter-argument is "but we know how a smartphone works", everyone who's done magic thinks they know something about how the world works. That's what gives them confidence that magic can actually help them. Also, there is a decent chance you personally have no clue of how a smartphone works. The number of individuals who understand that from beginning to end is sparse and most of that knowledge is irrelevant to day-to-day practice of an end-user.

Bonus: Are there other impossible phenomena (by real world standards) that they do not consider magical at all? Do these phenomena get any explanation for how they work?

All things that are not humans using spells, rituals, charms etc.. have other and often more specific terms. F.ex. a priest would roll their eyes at anyone calling a god "magic". What humans call " "gods" may be parts of either the material or spiritual worlds, but they're not "magic". Invoking them is.

("God" itself is another nebulous term that people in my settings affix rather freely to things that cause the sense of awe in them, including other people both living and dead. There might not be any essential quality shared between all "gods".)

For some of my settings, I've spent quite a lot of time detailing the philosophical and (pseudo-)scientific principles by which they work. These can allow for great variety of likely impossible things, such as travel through time or other universes, and may involve imaginative ideas such as the temporal world being a limited-dimensional shadow cast by a higher-dimensional eternal world of ideas, projected on the medium of mind-matter or information-energy (which are fundamentally the same thing, really, because panpsychism is true) by an immortal intelligence.

I could spend pages talking about these without ever using the word "magic", but I usually don't, because it ends with someone saying "that sounds like magic to me". To which the only response I can give is "Yes. All reality sounds like magic when you don't understand it."

[Mastikator]

In my setting? Magic the influence of beings and forces from higher dimensions channeled through the intentions of people that have come into contact with higher dimensions.
Nobody can discover magic in this world, it's not of the world, but it is something you can choose to let happen to you if it happens. When you choose, you don't get to pick what spell or mutation you get, instead you roll up 3 at random and pick from those, you then acquire a negative flaw using the same rules.
The theme is horror, weirdness.
On the mechanical side it rewards outside the box thinking, and because of its price, is only a detriment to anyone thinking in 3d or less.

There would never be a spell that lets you shoot lightning, instead it let you make yourself highly charged with static electricity. Then it's your job to protect your stuff and find a way to make that ability useful. What I want to convey is that someone who has magic isn't some kind of wizard, they're a monster.

[Grod_The_Giant]

Magic is one of three equally valid approaches to understanding the universe.

• You can break everything down into the Standard Model of particles and forces and get science.
• You can define everything in terms of the three fundamental aspects (energy, stability, and imagination) and get magic.
• You can frame everything in terms of consensus reality and "will."

Each approach is fully comprehensive and capable of explaining every aspect of existence as we experience it. They all have their own internally consistent sets of laws and rules that determine what kind of causes yield what kind of results.

The key is that all three are, ultimately, rooted in the same sort of uncertainty principles that govern our own understanding of quantum theory. When you dig all the way down to the most fundamental levels of existence, things exist in a sort of hazy, probabilistic state. It's only when it's observed that the wave function collapses and the particle (or equivalent) gains a definite location. And the nature of that collapse, the way the probabilities shake out, depends entirely on the nature of the observer.

(Magic behaves in ways we'd call impossible because under that approach, our thoughts are essentially real, tangible objects capable of exerting force on other aspects of existence. Meanwhile, a magician would call an internal combustion engine impossible because it's not being directed by an exterior force)

[KorvinStarmast]

I could spend pages talking about these without ever using the word "magic", but I usually don't, because it ends with someone saying "that sounds like magic to me". To which the only response I can give is "Yes. All reality sounds like magic when you don't understand it."

Thank you, Arthur C Clarke.

As to your definitions of magic, one was missing:
Magic (proper noun); one of the greatest basketball players to ever lace on a pair of sneakers.

Yes, I know his given name was Earvin Johnson

[Jay R]

It's called "magic". They know arcane magic from divine magic. They aren't necessarily clear on whether alchemy is magic or not. [Or most of nature's "miracles". I mean, you do that, and nine months later there's a baby? Surely that's magic.]

They know what a wizard, sorcerer, druid, or cleric is, but not necessarily what a mystic theurge or ultimate magus -- even if they are one. This is no different from the fact that a medieval European commoner may never have heard what a "European" was.

My gnome illusionist got really interested in illusions, and then in shadow illusions, but he never used the phrases "Master Specialist" or "Shadowcraft Mage".]

They don't know about hit points, armor class, or caster level, either -- but casters do know how powerful their spells are, and martials know about plate, chain, leather, etc.

I'm pretty clear on Clarke's contrapositive -- any technology distinguishable from magic is insufficiently advanced. So swords and bows aren't magic, but if somebody developed guns, most people would assume they were magic.

[Anymage]

In games I play in? Magic is just a list of powers on a character sheet. Most players in my experience are more concerned with their characters doing cool things than they are with the setting's underlying metaphysics.

If I were to make my own fantasy heartbreaker setting? The big things I'd want are limited/thematic power sets, ability to succeed or fail (ideally in a system with degrees of success or failure), and a cost more meaningful than spending a spell slot that will recover in the morning. I want a character's magic to clearly express who they are instead of being a grab bag, and part of expressing who they are involves limitations/costs/drawbacks as well.

[Telok]

As a programmer, of course I love, “magic is just direct calls to the underlying system running the simulation”.

If you that route you should go all in on the programmer tropes and have wizards trust magic and magic items as much as programmers trust their own work and Microsoft products.

In my setting 'magic' is a measurement of how much slippage there is in standard physics. Plus energy is conserved, so you need either a lot of extra work going on (slow, hard) or tapping into some massive conduit of otherworldly power (tricky, dangerous). Or the sacrifice of an entire lifetime of potential creativity and fate inertia. Some places have more slippage, others less, and there's even slippage in different directions. Because its 'slipping' theres different methods that work, some faster, some safer, some better in specific ways or places.

[JusticeZero]

Pathfinder game: Magic is abilities given by contracts with Numen and the Regents, who control access to the afterworld and are all Horrible. You have Power because you have made a Pact with an evil regional deity. They're all evil. All of them. There's nowhere you can go to not be under the domain of one or the other. And they give favors to those who are acting in their interest.

EZD6 game: It's just physics. You have to build a toolset to work with a sphere, and you don't get to pack more Spheres in that toolkit, but really you're just making yourself able to work with that type of effect. In the end, it's not different from learning to smith metal.
That said, if somebody is able to invoke the Misfortunes, they're pretty much just trying to have conversations with cosmic regulators. That's... also a skill.

[Draconi Redfir]

in my homebrew setting, Magic is kind of an extension of someone's / your soul, that gets stronger over time. And while magic in this setting isn't common, it is usually more powerful.

For example, in this setting, ANYONE can theoretically enchant an item, you, me, that homeless guy, etc. But it doesn't happen consciously. you don't sit down for twelve hours and focus on a knife in order to make it magic. Instead it's more of a passive thing, the item must be something you cherish and value that you hold onto and use regularly, for example: The necklace i got from my father as a child and have been wearing ever since. Over a long period of time, your soul will extend to include that item as a part of "you", making it magical in nature. There might also be some other sort of limit, such as needing to overcome some challenge with / for this item, I'm not sure yet, as not everyone just has magic items laying around, they're still quite rare outside of adventurers / the PC's. If you die in a dramatic or sudden way, there's also a chance that your soul will leave behind a larger then normal imprint on an item to make it magic, for example if i was assassinated by my enemies, then that sudden and unnatural death might cause my necklace to become a magical item suddenly, or become more magical then previously.

The tradeoff is that you can't do this with already existing magic items. If you find a +1 dagger, you can't make it a +2 dagger, you can't mix souls like that normally. as a tradeoff to THAT however, Magic gets stronger over time, it "ages like a fine wine" as i like to say. So if that +1 dagger was sitting in a temple for hundreds or thousands of years, it'd slowly become more powerful, becoming a +2 dagger, then a +3 dagger, then maybe a +3 humanoid-slaying dagger if it's owner was an assassin or mass-murder or the like.

Because of all of this, the spells you cast are also some extension of your soul influencing the world, and not everyone can do that. Wizards don't exist in this setting, so you don't "Learn" magic, you can either do it, or you can't. it's just something you're born with or is given to you by someone or something else.


One thing about all this is that it can affect the world in weird ways. There is a valley in this setting that is surrounded by all sides by tall mountains. In the world's equivalent of a caveman-era, there was a great and intense battle between at least two individuals, more like a primitive war with multiple individuals and factions probably. Whatever the case, the battle was so intense and the emotions felt there so strong, that the weapon which dealt the final blow surged with magic and became a magic item (or maybe it was already magic, not sure.) But this final blow was also strong enough to damage the weapon, cracking it and causing magic to slowly leak out into the air around it.

This magic item and the magic it leaked continued to grow in power for tens of thousands of years. Eventually some ancient halflings moved into the valley without really noticing anything, but as more time passed, the whole valley filled up with primal magic, growing stronger and stronger as time went on. It became this setting's equivalent of the feywild, and the plants and animals that lived in there adapted to it's presence and came to rely on it, those halflings becoming this setting's gnomes. Now they can't leave the valley without special equipment to keep them alive, and other races can't enter the valley without special suits, or the raw magic in the air would tear them apart.


So yeah, my setting has magic based on individual souls, and it grows more powerful over time like a fine wine.

[Amnestic]

It's entirely moon based.

Seven moons. Everyone gets born 'under' a moon, which determines what type of magic (mind, time, biological/organic, etc.) that person can use. Its growth similarly to muscles, in that if they use it a lot, it gets stronger, but a lot of people don't do weight lifting and distance training as part of their day to day, so their magic is just kinda 'there'. Using magic is a combination of the three B's: Belly, Brain, and Belief. Or, more specifically, energy (from food, in the belly), properly picturing its execution/manifestation (in the mind), and using your magic to will reality to shift in response to your change (belief).

There's a lot of drama among the rich and powerful about planning pregnancies/births around certain moon cycles to 'guarantee' they're born under the 'right' moon.

Magic is solely countered by obsidian, which is seen as the purest manifestation of the planet (as opposed to the moon). Obsidian handcuffs/cells are commonplace for especially dangerous and powerful manifestations.

The seventh moon - Chaos - obeys no laws or rules of physics regarding its position, nor does it respond to the three B's. Instead it's manifestation is entirely feelings based. You can't imagine "I want a fireball" and get one. The magic responds to your feelings (fear) and something happens in response. Due to their unpredictability, those born under the seventh moon tend to be hunted down and killed since they're unstable elements.

[Xihirli]

I tend to change it based on the game I’m playing; in D&D I have a whole thing on the cosmology and how every setting is ultimately part of the Far Realm, and therefore suggestible chaos that anyone can control if they learn how. Any restrictions on magic are imposed by the gods to limit the power of mortals.

But! If I’m going to make my own game with my own setting, or run Call of Cthulhu or monster hearts, I’m going to rest treat magic like a virus. It replicates itself by growing and multiplying in its host, and if fed enough it will take over and kill the host. Not on purpose, just because your blood is lightning now. It doesn’t have a mind, it just replicates and grows.

[Jay R]

I answered this question a couple of days ago. Here is some more discussion, including a change in my thoughts.

First, here is the relevant portion of the introduction to my world that I sent the players.

Spoiler: Introduction to Jay R’s game

Show

Gaea has the same general climate, terrain, and gross physical laws as our earth. Or at least, the parts of it the PCs will see early on has the same characteristics as certain parts of our earth. There is a single moon, and the tide follows it. Water flows downhill; mountains are usually part of a mountain range; as you go south, the climate gets warmer, etc.

But there are differences. It is not true that this world is run by the laws of modern physics except when somebody casts a spell. It has different physical laws. You have no idea if there are galaxies; the sun clearly and obviously orbits the earth, there are 9 or 10 known planets, which are bright lights in the sky that move relative to the stars. They are the moon, Mercury, Venus, the sun, Mars, Jupiter, Saturn, and two or three more that I will name if I ever need them.

The earth is not a planet; it is the unmoving center of the universe. There are (as far as you know) no electrons, neutrons, protons, plate tectonics, relativistic speeds, radioactivity, or 92 natural elements. [Of course, nobody on our earth knew of those things in medieval times, either, so who knows?]

Cold is an active force, not merely the lack of warmth. Electricity does not flow from highest to lowest potential (or wizards could not aim lightning bolts). There is no cube-square law (or there would be no giants, and dragons couldn’t fly). Gravity is not universal (or flight and levitation spells wouldn’t work). Some creation spells violate conservation of mass, and many attack spells violate the three laws of thermodynamics.

Cute stunts involving clever use of the laws of thermodynamics simply won’t work. Note that cute stunts involving the gross effects thereof very likely will work. Roll a stone down a mountain, and you could cause an avalanche. But in a world with teleportation, levitation, and fireball spells, Newton’s three laws of motion do not apply, and energy and momentum are not conserved. Accordingly, modern scientific meta-knowledge will do you more harm than good. On the other hand, knowledge of Aristotle, Ptolemy, medieval alchemy, or medieval and classical legends might be useful occasionally.

Based on my thoughts after my first response to this thread, I am now expanding that.

The laws of physics as we know them don’t apply, although the obvious gross effects (usually) do. Although gravity is not universal, nonetheless, rivers flow downhill. Stirring a solution mixes the ingredients, although many spells show that entropy is not always increasing. "Day" is when the sun is up, even though the sun revolves around the unmoving earth.

Some of the differences are obvious. There are four naturally occurring elements, not 92. Blood is red because of the sanguine in your humors, not the iron content of your hemoglobin. Lots of different species can breed true with humans.

So I have just decided that, besides arcane energy and divine energy, there are other, similar energies¹.

1. Life energy, which replaces most organic chemistry, doing many but not all of the same functions.
2. Spatial energy, which governs how planets circle the Earth in cycles and epicycles, how things fall and move, etc.
3. And probably more. This is a new idea.

¹This is not quantitative energy = kg*m²/s², as defined by modern physics. I'm using it as a generic term, and I wish I had a better word to use. If anybody has a better suggestion, please pass it on.

These all interact, as shown by the fact that many arcane and divine spells are identical, that spells affect life and space, and that some spells require biological components.

Are they all “magic”? I’m not sure yet, but the crucial observation is that the question is not about magic or energies, but about linguistics. What will we use the word “magic” to encompass?

[Similarly, we never changed what Pluto is. Pluto is itself, and we have no authority or ability to define what it is. We only changed what objects we will call “planets”.]

In any event, growing a tree from an acorn is life energy, or nature magic, or whatever you choose to call it. In a world with actual magic, the clear division we have between science and magic doesn't necessarily exist. [And if it does exist, people don't necessarily know where the boundaries are; see "Pluto", above.]

[KorvinStarmast]

IThe big things I'd want are limited/thematic power sets, ability to succeed or fail (ideally in a system with degrees of success or failure), and a cost more meaningful than spending a spell slot that will recover in the morning. I want a character's magic to clearly express who they are instead of being a grab bag, and part of expressing who they are involves limitations/costs/drawbacks as well.

I like the cut of your jib. The "magic" (Wit, Skill, Hedge Magic) in Robin Hobbs' Farseer books seem to fit that model, and I like how she did most of it.

I answered this question a couple of days ago. Here is some more discussion, including a change in my thoughts.

Good stuff, I intend to borrow liberally from that.

There are seven fundamental aspects of my homebrew world:

Fire
Earth
Air
Water
Spirit
Time
Location

When "magic" happens, one of the seven is being tapped into, manipulated, or harnessed.
And

There Is No Such Thing As A Free Lunch.

[LibraryOgre]

Generally, magic is a natural system within the world, access to which is provided by training, nature, or as a gift. So, "I'm telling the laws of physics to sit down and shut up" is wrong, because magic is part of physics in the game world.

[AuraTwilight]

Magic is an ecology.

The spirit world is an ethereal ecosystem of spirits, with gods, angels, fiends, fey, and so on being different only in their powers, allegiances, and so forth. They're not meaningfully different species.

The lowest entities, the microbe-equivalents, are spells. Most spells are useless, either not doing anything or only doing things that mortals can already do, like "blink your eyes on command" or "Convert consumed carbohydrates into fuel".

But spellcasters have found that some of them are useful, and that if they load them in their own brains (this is what memorizing is) and release them (by casting them) they can perform supernatural effects. Casting a spell is how they reproduce, so useful spells are Naturally Selected for. Metamagic is just deliberate spell-breeding.

It is possible for spells to become conscious; the easiest method is to load one in an empty body and give it full access to the brain and nervous system, but it can also be achieved through spell evolution and combination.

Higher beings like fey and angels are Multispellular lifeforms, covering not just their supernatural abilities but also the various "physical" traits they manifest with and their various cognitive functions. Gods are googolplex hiveminds of spells that are so massive they can afford to do nearly anything, and see no risk or loss in investing some of themselves into their clerics.

Sorcerers are mutants. Spells live in their cells in symbiosis the same way Mitochondria bonded with early cell life. They primarily descend from Spell-Blooded Princes; human/spell hybrids who cast spells through diplomacy mechanics; their spells are followers and henchmen who walk along side them as free-willed, awakened spirits.

[Cluedrew]

This is setting dependent of course. I have many settings and each has its own magic system[1] for the setting and the type of story I want to tell there. But picking one of the more generic fantasy examples: Magic is what magic was when magic was real.

Maybe I should phrase that differently. I learned some of the history of magic and this setting uses a lot of what I learned there. Magic is a craft, of using the strange an unseen parts of reality to some ends. So yes, manipulating fire with your mind is magic, as is a song that reinforces a shield, binding a spirit to stop a thief, but so is using herbs boiled in water to ease a headache. Sometimes people consider know these things wrote, like a black box spell, other times people have explanations of the underlying mechanics (some of which are right).[2]

As for impossible things, pretty much every impossible but non-magical feat that would show up in an ancient legend is on the table.

Using magic is a combination of the three B's: Belly, Brain, and Belief.

This both makes sense and is kind of a cute way to frame it. Yeah, nothing deep here, other than this is kind of proxy to me quoting a bunch of random posts in this thread and saying "I like that" over and over again.

[1] Even if it is a social drama about a blind person, there is a completely bespoke magic system in the background. I can't help it.
[2] Actually, some of the system has already evolved past this one, but this is the more unique answer.

[kieza]

Magic is a fundamental force like electromagnetism, and gravity. It's entangled with other fundamental forces, especially thought (which the sages think might be a separate fundamental force, or maybe just a specific phenomenon of magic). Think the right thoughts--generally weird, complicated thoughts that a mortal mind doesn't have naturally--and they resonate, distorting the background magical field and by extension the other fundamental forces so that something observable happens.

Some magic works by interacting directly with the fundamental forces: it channels lightning, manipulates heat and cold, applies kinetic energy, even accelerates entropy. This is arcane magic, and the only way to make it work is by training a mind to think through the contortions that produce the correct resonance. The more complicated the effect, the more complicated the thoughts...which is why arcane magic, for the most part, produces direct and unsubtle effects, and why arcanists who go beyond such magic tend to be a little odd. To heal a living body, or create substance out of nothing, or divine the future, is too complicated for a mortal mind to reach the necessary state...yet. Arcanists have, over the course of centuries, worked out a canon of thought-patterns that are reproducible and teachable, and ways to train new arcanists to think those thoughts. Which isn't to say that occasionally some savant twists their mind into a pretzel and manages to do something unheard-of...but generally, that kind of trick starts and ends with whoever came up with it. The spells that get passed on are the ones that you can teach another arcanist to think through, and every generation of arcanists comes up with a few new tricks and expands the boundaries of what arcane magic can do. Lately, they've worked out how to build physical devices out of magical materials that amplify resonance, or shape it, or have a resonance of their own without needing to be guided by a mortal mind. Some arcane magic has ceased being an art, and is now a kind of engineering, in which small, consistent, achievable resonances are arranged to achieve some greater effect.

Some magic works by using external magical entities as amplifiers. There are vast, complex minds embedded in, or growing out of, the background magical field, and a mortal who aligns their thoughts closely enough to them can cause them to resonate with one of these greater minds, amplifying their effect on the magical field. Most people think of these minds as gods, and build religions around the philosophies and thought-processes that resonate with them. Or, there are other phenomena, akin to standing waves in the background magical field, created by the aggregated thoughts and dreams of mortals, that manifest as spirits--of nature, of animals, of the dead--and can be resonated with in the same way. In both cases, it's easier to attain such magic...but it requires that the user internalize the thoughts that let them cast spells. Divine magic means believing in and living by the creed of your god; Spirit magic means being able to think like and empathize with inhuman spirits. This kind of magic can actually heal, and do many of the things that pure, arcane magic can't, but the things they can do are more specific, restricted to specific ways that an amplifying entity resonates. It can't be improved upon with time, which is why even though historically it has been the most powerful kind of magic, it is gradually losing ground as arcanists refine their tools and spells.