One thing that bugs me about Vancian Magic in D&D as I understand it is the following: How is "fire and forget" remotely believable when I can slot and ready more than one "copy" of a spell?

Say I have Fireball readied twice. This means I studied the spell twice, then throw one, then I forget that and would have to rest to ready it again, but what about the second? What am I missing?

I'm specifying D&D because that's the system with Vancian magic I know. I'm thinking particularly of video games based on D&D rules such as Planescape: Torment, Baldur's Gate and Neverwinter Nights, and my Dragonlance D&D 2E campaign.


7 Answers 7


That depends on your definition of "illogical." While I've personally never been a fan of Vancian magic due to cognitive dissonance ("It's like only being able to use the quadratic formula once on a test!"), there are in-fiction explanations for it.

Spell Preparation

What's important to understand is that the spells are not simply memorized, recalled, and then forgotten. They are specifically prepared, and then expended. The wizard remembers how to cast the spell, but is no longer prepared to do so.

"Memorizing" a spell is a misnomer. "Preparing" is the more appropriate word.

I don't have core rulebooks for D&D floating around at the moment, but this quote from the SRD says enough, I think:

[the prepared spell] remains in her mind as a nearly cast spell until she uses the prescribed components to complete and trigger it or until she abandons it.

In other words: during spell preparation, the wizard performs some ritual that "casts" his spells into the ether. He can either "cast" the same spell many times, or spread his allotment out over many spells.

Later, he performs some action (specified by the spell) that triggers the spell. That particular "casting" of the spell is completed, and is no longer available until the wizard is able to prepare it again.

In this way, the spells follow an internally consistent model, without relying on what the wizard should or should not be able to remember.

The Metaphor of the Surgeon

Suppose we use a surgeon in place of the wizard, and performing surgery in place of casting spells.

Spell preparation for our surgeon would be the act of preparing his tools: sterilizing them, arranging for the proper facilities to be made available, scheduling staff, and so on.

When the surgeon runs out of prepared tools, he can no longer perform surgery. He hasn't forgotten how to perform the surgery, but nonetheless, he is unable to proceed until he's had a chance to prepare again.

If the surgeon prepares tools for a single surgery, he can perform surgery once. If he prepares for two, he can perform it twice, and so on.

The Man Himself: Jack Vance

What discussion about Vancian spellcasting would be complete, without some input from Jack Vance himself? The following are a number of descriptions of spell casting, all taken from Mazirian the Magician:

On memorizing spells:

...They would be poignant corrosive spells, of such a nature that one would daunt the brain of an ordinary man and two render him mad. Mazirian, by dint of stringent exercise, could encompass four of the most formidable, or six of the lesser spells.
...Mazirian made a selection from his books and with great effort forced five spells upon his brain: ...

On having used a spell:

...The mesmeric spell had been expended, and he had none other in his brain.

On having spells at the ready:

"You may in any event, Mazirian. Are you with powerful spells today?"

I have yet to see Vance refer to the spell casting process with the terms "memorize" and "forget." So far, it's always been oblique, like the passages above.

I think that memorizing and forgetting is a very reasonable interpretation of the lines above. But I also think that their vagueness is important. When I read them, I think of an other-worldly force that the wizard has to hold ready with some kind of psychic "muscle" (like telekinesis). To me, the spells are "in his mind" in the sense that someone possessing you is "in your mind," not in the sense of memories.

But that's purely interpretation.

Jack Vance vs. D&D

In reading Vance, I found the Vancian system much more appealing than I ever found it in D&D. I've put a little thought into it, and here are some of the key differences that I've been able to spot. Your mileage may vary; some of these might not apply to you.

  • Vancian Magic Takes Skill

    Vance's spellcasters take hours of preparation combined with years of experience to select a handful of spells that they can use to maximum effect. It also helps that the author of the story actively wants them to use exactly all of their spells.

    To recreate this on the table-top takes an enormous amount of skill on the part of both the player and the DM. For the player's part, they need to know the spells well enough to make a good selection, need to know the world well enough to know what they're going to encounter, need to be clever enough to make spells fit unexpected situations, restrained enough not to spend spells heedlessly, and patient enough to thoroughly plan and research their upcoming adventure.

    On the part of the DM, the DM needs to present a world consistent with published materials, vary encounters enough that the optimum spell build isn't just "Fireball, Fireball, Fireball, Magic Missile," and find some way to give the players the ability to do advanced legwork without having it take over the plot (because after all, if we wanted to spend an adventure planning the adventure we'd be playing Shadowrun).

  • Vance's Spells are Powerful

    In Vance, one spell solves most problems. Attack spells kill their targets. Protection spells render the user invulnerable. Blessings can last days or years.

  • There's More to Vance's Wizards than Spells

    Vance's wizards spend a lot of their time not casting spells. Whether they fall back on powerful magic items (on the scale of "I am immune to all magic"), magic-that-isn't spells (there's a number of instances of wizards "muttering counter-curses" or otherwise using "magic" that they haven't prepared), or even engaging in outright sword-play, Vance's wizards have options when a spell doesn't suffice.

  • Vance's Wizards are Limited to Concurrent Spells, not Spells Per Day

    This is a matter of "gameplay" vs. "realism." Vance's wizards have a limit on the number of spells available at one time, without easy access to replenish their spells. D&D wizards are limited to the more "gamey" spells per day, with ready access to their spell books.

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    \$\begingroup\$ Imagine that the average ritual spell takes about 10 minutes to cast (say fireball). It would be really inconveniant for a wizard to take that many turns casting one spell, so Wizards devised a way to cast the spell 99% and hold that in-potential, requiring only a second to finish it and send it on its way. Now when you cast it, it "leaves your mind" you no longer are holding it, it is gone, but if you have two prepared you have another charge stored internally. \$\endgroup\$
    – Ashterothi
    Commented Feb 2, 2012 at 16:58
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    \$\begingroup\$ note that, once upon a time, D&D did officially use the "memorize" and "forget" terminology. this was dropped in the transition from AD&D 2E to D&D 3E, which was, in my opinion, the single best official fluff decision in the history of the game. the "memorizing" fluff was flatly idiotic. \$\endgroup\$ Commented Jan 26, 2014 at 20:04
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    \$\begingroup\$ @MatthewNajmon I've heard the earliest editions didn't use the 'memorise and forget' terminology either. Makes me wonder where things went wrong; It must have seemed like a good idea at the time. \$\endgroup\$
    – GMJoe
    Commented Jun 23, 2016 at 0:10
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    \$\begingroup\$ It's like charging a capacitor \$\endgroup\$ Commented Jun 29, 2017 at 13:18
  • \$\begingroup\$ Now it seems a little less arbitrary, thanks \$\endgroup\$
    – András
    Commented May 28, 2018 at 11:27

Pre-4E D&D's magic system, ignoring sorcerers, is best explained by a visualization of spells as "knots" of mana.

For wizards, these knots are made using the spellbook page as a form; the spell literally can't be shaped without its assistance. The shape of the knot determines its function. Further, a wizard can only hold a few at first, but as they improve in ability, they learn how to tie more of them to themselves, as well as channeling more mana daily. At "Casting," what's being done isn't actually casting, but triggering the mana-knot to unfold so as to have the effect.

Sorcerers somehow have their own bodies as forms for the knots, and can tie those mana-knots fast.

Clerics don't tie the knots themselves; they are granted pre-tied knots by their deities.

This is based upon Bill Willingham's explanation of magic in the Ironwood graphic novels.

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    \$\begingroup\$ It should be noted that Bill Willingham played with E Gary Gygax... \$\endgroup\$
    – aramis
    Commented Feb 2, 2012 at 17:25
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    \$\begingroup\$ Zelazny and Brust use similar descriptions of spell preparation in their fantasy universes -- preparing a spell involves the meticulous construction of a web or pattern of magical energy within your mind. \$\endgroup\$
    – starwed
    Commented Sep 10, 2012 at 23:36
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    \$\begingroup\$ @starwed YES! I've been struggling to remember one familiar fantasy settings which used a similar system, until I saw your post and immediately recalled second half of the Amber series. Also it worked like that in Joel Rosenberg's Guardians of the Flame series. \$\endgroup\$
    – Maurycy
    Commented Oct 23, 2012 at 19:36
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    \$\begingroup\$ Rolled back because I do not consider 5E to be best visualized by the Willingham version - it's not the same as pre-4E, nor as 4E. \$\endgroup\$
    – aramis
    Commented Feb 27, 2015 at 22:24

I read in the AD&D 1e core rulebooks that each spell has a point at which it can be "paused". So that means that each spell is actually a ritual by default, and that the wizard actually casts 99% percent of each spell, repeating it for each copy of it they cast. They leave out the last few motions so that the spell can be finished, its effect taking place. The spell slots represent the wizard's inner power, their ability to take the mental stress of the arcane equivalent of an inert bomb, to keep their spell paused until they wish to cast it.


The quote from the book is something like; " A Mage spends his time preparing the spell and the locking the arcane energies in their mind till a point when they cast it, at that time the spells energies are wiped from their mind until they prepare it once again." Gary Gygax loved the Dying Earth fantasy series and in these books wizards actually forgot their spells as they cast them and had to re-learn them. It is simply his way of "tipping his hat" his favorite books series.

Specific citations from AD&D 1e and The Strategic Review

  1. DMG AD&D 1e p. 40:

SPELL CASTING All magic and cleric spells are similar in that the word sounds, when combined into whatever patterns are applicable, are charged with energy from the Positive or Negative Material Plane. When uttered, these sounds cause the release of this energy, which in turn triggers a set reaction. The release of the energy contained in these words is what causes the spell to be forgotten or the writing to disappear from the surface upon which it is written.

  1. PHB AD&D 1e p. 100.

SPELL CASTING Each character able to cast spells can remember only a certain number at any given level. (This number can be modified by magical means.) Once a spell is cast, that particular spell is wiped from the mind, forgotten, but another spell of the same type con still be remembered, i.e. the spell caster can hove several of the some spell memorized and prepared for, within the number limits for his or her porticular class and level.

  1. Strategic Review #7 (April 1976) page 3.

The basic assumption, then, was that D & D magic worked on a “Vancian” system and if used correctly would be a highly powerful and effective force. There are also four basic parts to magic: The verbal or uttered spell, the somatic or physical movement required for the conjuration, the psychic or mental attitude necessary to cast the spell, and the material adjuncts by which the spell, can be completed (to cite an obvious example, water to raise a water elemental)...
All spells were assumed to have a verbal component. Each and every spell (not found on a scroll or otherwise contained in, or on, some magical device) would be absolutely mnemonic, magic-users would have to memorize the spells they wished to have available, and when a particular spell was recalled and its other parts enacted, then the memory would be gone and the spell no longer available until it was re-memorized (thus the magic-users’ spell books!).


For an in-game rationale, I've always considered it the equivalent of inscribing a scroll. However, instead of rare inks and vellum, the mage partitions off a corner of their mind and uses complex mental constructs developed through years of training to set the same kind of text-based matrix to hold the magic. Then, the spells in their head work very similar to a collection of re-writable scrolls. You're not "doing a task that you then forget how to do", which is hard to reconcile. Instead you're reading out a section of memory, which releases the associated magic, and wipes that slate clean.

I also like to employ common mechanics across the game whenever I can, because it gives me a solid framework to adjudicate unexpected situations and bizarre player ideas.

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    \$\begingroup\$ As I recall, this is basically how the Dragonlance saga described it when Raistlin cast his magic. \$\endgroup\$ Commented Jan 23, 2013 at 20:10

It probably makes more sense if you know/remember how spell prep worked in AD&D (PhB pg. 40): 15 minutes (10 min in AD&D 2e, revised PhB pg. 107) of prep time per level of a spell instead of the 1 hour total each day (which would be an awful thing to house-rule unless you never want a caster to play in your game or something). You still have to prepare your spells to be ready to complete quickly, it just no longer takes the better part of a week to do so after you gain a few levels.

Think of it kind of like like an old black powder gun where you have to pour in the powder, tamp it down, add the wadding, drop in the ball, then aim and pull the trigger. The wizard has to prime the pump first by preparing the spells in order to be able to simply aim and pull the trigger later. A fireball that took an hour (600 rounds) would not be especially useful in most combats.

If it really bothers you as a GM and the non-casters are all out of the ToB or something, houserule that they can cast spells outside their normal daily allotment if they spend an hour per spell level without any interruptions whatsoever casting it. As a result you would probably see wizards casting a lot more of those useful quality of life, travel and help NPC-style spells like plant growth that you pretty much never see used for their optional reason.

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    \$\begingroup\$ Years late but note that this answer is partly incorrect - AD&D spells are 15min per level to memorise, not 60. You also have to be rested, which basically means a good night's sleep before starting to memorise any bunch of spells. \$\endgroup\$
    – Nagora
    Commented Jun 3, 2017 at 22:05

The theory that my campaign runs on is that a wizard forms a spell much the way a computer programmer writes a program. The wizard has a complex series of runic notations which function very much like a programing language. The wizard will then format the spell, list the forces to be used and the symbolic correspondences that make the spell "work". It is important to note that given the rather extraordinary length of time it takes for a player to research an entirely new spell (weeks if not months with costly materials totally burned up) I would guess that "debugging the spell takes a long time. Once the wizard has an effective spell script he/she will "compile" and "download" the spell (compile and download while not fantasy words in and of themselves match the description I am looking for). Then in the moment of truth, the wizard will enact the components (somatic verbal etc.) that essentially call up and run the spell, sort of like an executable file. The only difference being that the actual data for the spell is corrupted by the power of the enacted spell. I am from the silicon valley in California so forgive me if that was to... nerdish? I hope that this might help in the visualization of wizardly magic in D&D.

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    \$\begingroup\$ Apropos of magic as programming, see: Wizard's Bane by Rick Cook. \$\endgroup\$ Commented Feb 16, 2014 at 8:48
  • \$\begingroup\$ A self-modifying program. \$\endgroup\$ Commented Jul 19, 2014 at 20:19
  • \$\begingroup\$ We always used the metaphor of charging a capacitor (for those who understand EE) or loading the clip for an M-14. You have to reload to fire again. \$\endgroup\$ Commented Jun 29, 2017 at 13:22

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