I'm working on a story (see here) where the way magic works is ... difficult, to say the least. Most magic occurs naturally, either through ley lines (naturally occuring lines of magical energy that line the world and are invisible) or through magical creatures (i.e., unicorns, pukkas, etc. Haven't quite figured out how they work yet, so ignore this). Structured magic, or magic that can be used for specific purposes by characters in the story, is (generally) predictable. E.g., mixing juice from a mandrake, unicorn horn powder and a wolf's spirit under the light of a blood moon in a cast iron cauldron will give you a potion capable of making anyone fall in love with you. (Not literally, just a hypothetical example). However, even if you follow all the instructions, there is a chance that the potion will, instead, cover the drinker in purple warts for 6 days. How would I go about designing and justifying this kind of magic system/ should I even make a magic system like this?

How do I even design something like this? Also, if it's not too much trouble, please include ideas on how to justify this in-universe, if possible.

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    $\begingroup$ This is way too broad a question, and a brainstorming one at that, both of which aren't a good match for this site. Designing your world is up to you, this site is here for you when you bump into concrete obstacles along the way. $\endgroup$
    – Joachim
    Commented May 10 at 22:25
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    $\begingroup$ @Talbot It is illogical to ask for advice in designing an inconsistent magical system. No matter how much a writer tries to make their world consistent, if the story becomes popular, some readers are bound to notice inconsistencies. $\endgroup$ Commented May 10 at 22:47
  • $\begingroup$ The word magic already tells us it is not science and we can expect inconsistencies and special cases. $\endgroup$
    – KalleMP
    Commented May 11 at 11:05
  • $\begingroup$ The unicorn had a wart on its horn, what did you expect? Better not buy the cheap powder. $\endgroup$
    – DonQuiKong
    Commented May 12 at 16:33
  • $\begingroup$ I can't help but feel that you're asking for consistent inconsistencies. Lawrence Watt Evans does a great job describing a magic built from an incomprehensibly complex set of rules in "With a Single Spell," so I'd suggest that as a reference, but otherwise you're asking a question that couldn't possibly have a single answer. $\endgroup$ Commented May 14 at 17:12

7 Answers 7


Oops, you forgot that Mercury is in retrograde!

The problem is not whether you followed the instructions correctly, it's about all the variables that the instructions forgot to account for. Your average potion will work out just fine if you follow the instructions, but there are so many variables at play that you simply don't know about. Things like when some alignment of the planets is wrong, or when your dog's fur on your lab coat gets mixed in by accident, or when a unicorn farts too close to your lab, etc. is going to have a meaningful effect.

Truly great alchemists know exactly how to make a potion that will almost always go right, but the instructions to make sure all of the possibly knowable variables are accounted for get so extensive, that even the simplests of potions require an entire tome unto itself and a computer chip quality clean room... since most alchemists are not that dedicated, they just work off of the cliffsnotes recipes in their kitchens and everything usually works out fine.

Why Science and Industrialization would lag behind

Even if your setting has the technology to make a potions clean room, implementing one in practice will be very difficult. All that you seemingly need to do to better control the production of your potions is to create a factory that just produces a specific potion where you can apply all the specialized knowledge in the world about this one potion in one place. After all, it's a lot easier to be precise when you are working at a bigger scale and with more expensive, high-tech equipment and supplies... but even if you have 1000 years of research telling you how to safely store those phoenix feathers you need, no one has ever tried storing them in bulk before. As it turns out, a pile 1000 phoenix feathers and a super blue moon is all you need to create a new and highly destructive spell that no one has ever tried before. Even having taken proper precautions by testing to see if you could safely store those feathers like that is not enough because the tests can't account for every possible rare astrological occurrence: real world variances are just too hard to predict. In fact, there are so many unknowns where bulk storage are concerned and certain magical cycles are so rare that it would take 100s of years and immense resources to determine if and how to set up your first large scale factories safely. With scalability being such a problem, creating potion clean rooms will simply not be economically viable; so, unreliable cottage industry potions will simply be a better investment.

History tells us how science can hide beneath the surface of magic

Chemists, metallurgists, etc. faced a similar problem to this in the 1700s. They knew parts of the periodic table, and could make some general predictions about the missing bits, but they did not have enough information yet to perform chemistry in a reliable and predictable way; so, lab experiments often ended in unexpected ways. Today, the periodic table and various chemical analysis tools allows chemists to make good ballpark predictions about various how their ingredients will react and to calculate exact ideal ratios of those ingredients. But 300+ years ago, all they knew was that they needed to add X to Y to get Z, but they did not fully understand what their materials were or how to test for contamination. They often found ways to reduce certain contaminates through ritual purification methods, but they did not know why these things worked or how to tell if their starting materials were good enough... but the important side effect of this is that they often did not know why things went wrong: so they chalked it up to magic. For example, today's museums are full of tools and weapons that shattered because the blacksmiths the of the day did not know about Phosphorus, Sulfur, or Cobalt contamination, and when you read their treatises, they are full of very precise, and scientific sounding proccessess interspersed with explanations of how goblins might curse your ore when you are not looking or the importance of prayer and rituals.

So if you wish to maintain that there is infact a science to magic AND that its unpredictable, you just need to recreate this historical context in your setting. A modern society could maybe piece together parts of the "Magic Periodic table" that tells them how to predict magic, but if you look at how incomplete the table of elements was in the 1700s when we were trying to figure out a simple 2 dimensional table, imagine how much more difficult it would be to define a much more complex table of magic which might require an 11 dimensional chart to define and contain the millions of "elements" that are constantly transitioning as they interact with ley lines, astral orientations, etc. It could even be well understood by your wizards that 90% of the table of magic is still undiscovered: they know where the holes are in it, they just don't know how to fill it yet.

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    $\begingroup$ Bonus points if somebody sells insurance for days of work lost to purple wart outbreaks. $\endgroup$
    – g s
    Commented May 11 at 6:30
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    $\begingroup$ This is the first thought I had reading the question, and IMO it’s one of the best ways of allowing internal consistency while still having high-level unpredictability. It also all but ensures that you will have some number of ‘research alchemists’ who have a life goal of figuring out, for certain, exactly what is needed to produce a given potion correctly 100% of the time. $\endgroup$ Commented May 11 at 10:56

It's magic, not science.

Science is anything that is deterministic, repeatable or probabilistic. A recipe involving unicorn horn, wolf spirit and boiling can be analyzed, separated and industrially produced, even if the wolf spirit requires advanced refrigeration techniques, and full-moon-light needs special lamps. It may involve strange creatures and things not easily obtainable in this world, but clearly they exist and can be found in yours.

Science seeks to explain and understand, so to prevent explanation, magic must be inconsistent in at least some way. Why is it inconsistent? No one knows because if they did, it would no longer be magic.

So in your universe, magic is inconsistent by it's nature. What works for one person in one location will not work for another person in another place.

Note that books that include magic that is actually magic and not an unknown science or extra-human-senses are very very rare.

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    $\begingroup$ Interesting. I have actually never thought about it like that. Usually, I am very "need to understand, everything must make sense" about my worldbuilding. This is a very good point, and, coincidentally, fits neatly into how I wanted to make this story. Thank you! $\endgroup$
    – Talbot
    Commented May 10 at 19:23
  • $\begingroup$ @Talbot just because there is a logical explanation for everything doesn't mean it's accessible to anyone but the guy who invented it first, powered by a special concoction of mind altering liquids that we too have no idea what it was. And junior magicians are bound to copy spells from spellbooks without any hope of understanding. They don't dare experiment. The last guy that did was found dead under a 100m titanium sphere and the one before them apparently plummeted from the edge of space and onto their bedroom floor while leaving the ceiling untouched. $\endgroup$ Commented May 11 at 8:53
  • $\begingroup$ In other words, the three most basic scientific maxims - translation symmetry, rotation symmetry, and time symmetry - do not hold, since the same process can yield different results at different orientations, locations, or times. In other words, momentum, angular momentum, and energy are not necessarily conserved, according to Noether's theorem. So yes, inconsistent "science magic" does screw over all our understanding of the Universe, in case anyone was wondering. $\endgroup$ Commented May 13 at 2:13
  • $\begingroup$ Magic does not need to be inconsistent to seem inconsistent. For example, early iron working was considered a form of magic, even to cultures that believed in a scientific method, because indiscernible contamination due from things like Phosphorous, Sulfur, and Cobalt made iron smelting a largely unrepeatable process. One week you forge an unbreakable sword, next week, you do the exact same thing and your iron cumbles on your anvil. In Japan, it is still common to perform prayers and purification rituals as part of the steel production process. $\endgroup$
    – Nosajimiki
    Commented May 13 at 19:44

There's manna in the air.

The magical users require a basic essence to be present during a spell's casting, this is manna. It may or may not be possible to collect and concentrate this, it's up to you - but perhaps certain plants do collect it.

Plant-based magic relies on the quality of the inherent magic that was present, right at the spot where it grew when the seeds of the plant germinated, or sometimes when the flower-petals first opened.

This sounds great in principle, but magic has "weather". Sometimes the metaphorical sun shines and magic collects like it should in the right place at the right time.

However, sometimes it's raining, sometimes windy, sometimes - with the magic-user completely oblivious to the fact until it's too late - there's a force 9 gale blowing and it's hailing invisible-ice-rocks.

This will give some batches of herbs from the apothecaries a bit of a reputation for being "good" or "OK", or "not great", or "disaster, give only to your worst enemy if you want them to suffer".

Then there's the properties of the current mana available in the air as the spell is cast, this adds an extra dimension of uncertainty - with pockets of "bad manna" being uncertain to predict.

Perhaps the magic users say a little prayer to the gods of magic-weather at the start of each day, and give a note of thanks at the end.

Perhaps there are almanacks of weather that may be consulted from season-to-season to aid in finding the best time to cast and the best herbs to cast with.

Perhaps there are charlatans that practice "weather divination" services to forecast your best places and times to practice.

Perhaps occasional genuinely mana-weather-sensitive individuals - these would be highly valued.

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    $\begingroup$ dental patient Excellent answer! I was actually considering doing something similar, where spells cease working properly if the original caster dies, but realized that wouldn't work. Plants and weather is SUCH a great idea. Thank you!! $\endgroup$
    – Talbot
    Commented May 10 at 18:52

Aristotle was right.

With science, things work off of mechanistic logic. Effects have causes, $2H_2O \to 2H_2+O_2$, $\pi = 3.14... = {C \over d}$, etc. Importantly, things don't have "personalities"; chemists may say a nasty chemical "really doesn't want to exist" or "hates everything else with a passion", but they don't mean it literally. The chemical doesn't have a personality; it just is.

Magic works off of a more "poetic" logic. Inanimate or conceptual things have metaphysical attributes that affect what they're used in. Samhain is the best night for fiendish acts because it is fiendish. The number seven really is perfect. Chairs have a certain "chair-ness" that makes them suitable for sitting on, and which can be transferred to something else using magic (hence why magic-users are able to fly around on broomsticks and swords without crushing their private bits.) Objects rise or fall because they have a certain "place" they naturally belong in the music of the spheres.

Importantly, while people generally consider only a single aspect of something's Form (or Idea, or morphē, or whatever's in style this week), in reality it has many aspects. Furthermore, the environment has an effect too.

For example, let's consider a love potion, designed for a woman to give to a man who isn't taking the hint. It has several ingredients:

  • Belladonna ("Beautiful Lady")
  • Unicorn horn (associated with male virility)
  • Alcohol (because it loosens up morals)
  • Mandragora foemina (female mandrake) root, associated with finding love
  • Gold dust (because power and wealth is attractive)
  • A lock of the brewer's hair (to establish whom the target should be falling in love with)

On paper, these should form a love potion when combined. However, there are a few problems:

  • In addition to virility, unicorns are also heavily associated with purity.
  • Alcohol gives the user beer goggles, but it also causes performance issues.
  • Mandrake root is also attributed with anaesthetic properties.
  • (Speaking in superstitious terms) beautiful women are often fickle and mean-spirited.

If these attributes make it into the potion instead of the intended ones (such as if you brew it in the bleak, cold midwinter), you'll end up with a potion that makes the target actively disinterested in you, not fall in love.

EDIT: By the way, this is why magic-users tend to be so eccentric. In the same way that science's working assumption that all questions have natural answers tends to produce atheists, magic's "poetic" (or "narrative") logic tends to produce people who think in insane troll logic.

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    $\begingroup$ Interesting take. Thank you very much for the ideas. This is similar to another answer I was given, but your's is both unique and thought provoking. Thank you again! $\endgroup$
    – Talbot
    Commented May 10 at 20:56
  • $\begingroup$ @Talbot Thanks! If you're willing to wade through a bit of dry language, I highly recommend skimming the chapters on Plato and Aristotle in A History of Philosophy, Volume I. Copleston does a very good job of explaining these concepts. $\endgroup$ Commented May 10 at 21:01

The mental component

Come now, why would mixing mandrake juice, unicorn horn powder and wolf's spirit ever create a love potion? Such nonsense! No, those are merely necessary conduits for the silent incantation of the alchemist mixing the potion. If mixed by some mechanical contraption or a soleless being, nothing would happen. Why should it?

This mental component isn't as simple as just thinking of the words of a spell. No, a key part of potionbrewing is entering a certain zen-like state of mind and focus on what you want to accomplish. This state of mind, combined with your goals, the ingrediens, and other surrounding effects (moonlight, etc.) combine to form a magical potion.

The problem? The amount of focus and mental discipline this requires. The mind is easily distracted and stray thoughts are bound to pop up from time to time; sometimes subconsciously. Have you ever tried to not think of a specific thing? It's borderline impossible. A distracted alchemist, whether they know it or not, may let those random influences taint the potion. For the obvious things, like being interrupted mid-brewing, they may preemptively toss out the batch. For the more subtle things, they may not be certain or at all aware that something went wrong, and bottle up the potion.

While skilled alchemists may have more experience controlling their mind, and thus have a higher success rate, there are no guarantees ever; even the best occasionally fail.


Pigeon Dances

B.F. Skinner experimented in animal psychology. He created an experimental setup which has been given his name: Skinner boxes. Their purpose was to create an environment where we could test the effects of operational conditioning.

One of the fascinating results was pigeon dances. A pigeon in the box would do their thing until food was randomly provided. The pigeon would try to figure out the cause of this. They'd try thing like twitching their wings or bobbing their head. Sometimes they'd get lucky, and do something right as the food arrived. Soon the pigeons would engage in elaborate dances trying to outwit the randomness. Skinner even showed that they could teach each other the dances if they could see each other through a plexiglass pane.

You can make an inconsistent system that has a sense of Eldritch horror, or you can just make the inconsistency the result of randomness. The recipes are not recipes, as much as just things that worked in the past.

Anything but randomness is just going to create a new level of consistency. And even randomness leads to interesting patterns. There's the "black swan" pattern that argues that unusual things occur more often than we think they should.


You don't need to design an inconsistent magic system; it already exists in our world. Our magic consists of affecting the consciousness of other beings, effectively making them feel more like doing what you want. The being in question can be yourself, other people, or they can be immaterial; but material or not, they all have a mind of their own, quite literally. If they think you are asking for too much, or with false pretences, or if doing a favor for you collides with their other plans - then they will not help you, even if you follow your potion-making instructions to the letter. And of course all these beings are not just passively awaiting your requests, and may simply decide to try to play a trick on you.


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