Can a Magus learn Wizard spells by conducting independent research?

Question

By the rules of non-downtime Independent Research:

Independent Research

A wizard can also research a spell independently, duplicating an existing spell or creating an entirely new one. The cost to research a new spell, and the time required, are left up to GM discretion, but it should probably take at least 1 week and cost at least 1,000 gp per level of the spell to be researched. This should also require a number of Spellcraft and Knowledge (arcana) checks.

This implies that a Wizard can duplicate the effects of any spell across any spell list, RAW, and add that spell to his spellbook. This follows from both "duplicating an existing spell," as those spells exist on other spell lists, and "creating an entirely new one," as those spells do not exist on the Wizard spell list.

Of note here is that no part of the Magus class entry allows them to add new spells to their spellbook by any means other than leveling up. Here are the lines applicable to a Magus learning new spells:

A magus may know any number of spells.

At each new magus level, he gains two new magus spells of any spell level or levels that he can cast (based on his new magus level) for his spellbook. At any time, a magus can also add spells found in other spellbooks to his own.

A magus can learn spells from a wizard’s spellbook, just as a wizard can from a magus’s spellbook. The spells learned must be on the magus spell list, as normal. An alchemist can learn formulae from a magus’s spellbook, if the spells are also on the alchemist spell list. A magus cannot learn spells from an alchemist.

Another way that the Magus can probably learn spells RAW is via Knowledge Pool. See this question and its accepted answer for details, though this may change from table to table.

RAW, the Magus cannot research spells. However, it seems reasonable that RAI this prepared caster with a spellbook can research spells like a Wizard, and indeed this would appear to be a common house rule.

Under the assumption that this house rule is in place, the Magus then falls under the same category as the Wizard with regards to researching spells.

The logical conclusion from this is that if the Magus can research, the Magus can then research spells from any list, with the most obvious and least-controversial non-Magus list being the Wizard's spell list.

Would it be unbalanced in a typical campaign to allow a Magus to research Wizard spells?

Answer 1

Independent research, very much intentionally, has zero rules about what spells any spellcaster can and cannot research. There is some guidance for the GM about what to accept or not, but it is only guidance. There are no “rules as written.” What was written was literally “ask your GM to make an ad hoc decision for the particular spell you are interested in.”

Instead, the independent research rules only define what, in character, you have to do to research an original spell after your GM has agreed that it would be an acceptable spell/what spell level it would be.

So the answer to your question is, and will always be, and can never be anything other than, ask your GM. If your GM is OK with your magus researching such a spell, then yes, you can. If your GM is not, then no, you cannot. No other answer is possible, and any answer claiming otherwise is simply wrong. The answer you seek is explicitly not provided by the rules.

Answer 2

Answer: Per GM discretion, you could interpret Independent Research to apply to non-Wizard prepared Arcane casters that use a spellbook.

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RAW, a spellcaster that uses a spellbook can only cast spells on their own spell list. If they read another class's spellbook, they can't necessarily cast all of those spells. This quote is taken directly from Archives of Nethys:

From Magus class, class feature Spellbooks:

A magus casts arcane spells drawn from the magus spell list. A magus must choose and prepare his spells ahead of time.

A magus can learn spells from a wizard's spellbook, just as a wizard can from a magus's spellbook. The spells learned must be on the magus spell list, as normal. An alchemist (see the Alchemist description) can learn formulae from a magus's spellbook, if the spells are also on the alchemist spell list. A magus cannot learn spells from an alchemist.

That quote about independent research is from the Core Rulebook, and an important note about the Core Rules is that Wizards were the only prepared Arcane Caster in Pathfinder at the time. To my knowledge, no newer books have been published with any sections regarding Independent Research. It is reasonable, to me, that a GM could make that house rule to allow prepared Arcane casters to perform Independent Research.

Furthermore, regarding what spells a Magus can copy from another spellbook, a Magus can only copy spells from spellbooks that naturally appear on the Magus spell list. If a Magus reads the spellbook of a Wizard that contains an Indepently Researched spell not on the Magus spell list, then the Magus cannot learn that spell through copying from a spellbook. A Magus can, however, Independently Research such a spell if the GM allows Independent Research.

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On the question of balance for a "typical" campaign, allowing a class so specifically designed to synergize with blast spells to have their pick of every blast and debuff spell in the game (albeit at a price) is a potential recipe for disaster, in addition to having utility that Magi are not intended to have. My group's GM flat out bans prepared full casters because we all play intelligently and decently optimally (side note: we'd also spend 80% of our session time planning and 20% executing if we had this kind of power). I know for that GM's other group that they can play whatever classes and races they want because they play sub-optimally across the board and don't abuse the power they're given.

I would be cautious with giving your players this kind of power. Talk with your Magus player and figure out what they're trying to do with it. It's important to understand how competently and effectively such a freedom would be used. Even just access to the Wizard spell list on a Magus in the hands of my party would crack a campaign wide open. Bestow Curse on a Magus is a terrifying idea and I never want to have to GM against that.

On the opposite end of that spectrum would be the players who wouldn't utilize Independent Research. Decision Paralysis is a serious consideration for less experienced players, so I would withhold Independent Research until they knew the game better and understand how to create a solid caster character.

In summary, the most balanced way to implement Independent Research with non-Wizards is in a game with experienced and knowledgeable players who will use IR for non-broken purposes and play suboptimally on purpose. Experienced players can break the game if not kept in line, and inexperienced players will not typically utilize this very well.

Answer 3

I’d like to throw my hat into the ring here, not for the sake of hoping this is a correct answer, but in an attempt to give, as much as possible, a complete picture.

TL;DR: Magi have a class feature they can choose to take over other class features that allow them to get wizard spells. By house-ruling that a magus can learn a wizard spell through independent research, the in-class feature becomes moot, opening their choices to other features more readily in a way the developers may have not intended. This could make an already powerful class unbalanced.

The wordings of the sections quoted are very specific, probably as intended by the game developers. Wizards would be defined as a class of their own that is separate from Magi, even if the flavor text for both classes indicate that they both undergo a fair amount of study to achieve arcane power. Lore wise, maybe wizards gave up practicing with the blade to do this type of research, while magi would give up further research by honing their skills with their weapons. Hence, I think it would be a bit of a stretch to say that magi could undertake independent research as wizards could (not saying it’s impossible, I know a lot of fit researchers, but maybe not to the extent that Magi are as fighters).

For Independent Research from Addings Spells to a Wizard’s Spellbook

A wizard can also research a spell independently, duplicating an existing spell or creating an entirely new one. The cost to research a new spell, and the time required, are left up to GM discretion, but it should probably take at least 1 week and cost at least 1,000 gp per level of the spell to be researched. This should also require a numbe of Spellcraft and Knowledge (arcana) checks.

(Bold is my emphasis)

Here the rule says wizard, which implies only the wizard is capable of duplicating an existing or creating an entirely new [spell].

For Knowledge Pool

At 7th level, when a magus prepares his magus spells, he can decide to expend 1 or more points from his arcane pool, up to his Intelligence bonus. For each point he expends, he can treat any one spell from the magus spell list as if it were in his spellbook and can prepare that spell as normal that day. If he does not cast spells prepared in this way before the next time he prepares spells, he loses those spells. He can also cast spells added in this way using his spell recall ability, but only until he prepares spells again.

(Bold is my emphasis)

The magus can treat any spell from the magus spell list as if it were in their spell book. It does not indicate that the spell is from another class’ spell list. Further, while it is a tentative “yes,” if I were particularly punctilious about the wording of the rules, a magus wouldn’t/shouldn’t be able to do this because there’s nowhere in the Magus rules that indicate they can do it. If they did, there would have been a rule in there that says “a magus can replace and copy spell books in the same way a wizard does,” as they had done with the witch’s familiar:

At 1st level, a witch forms a close bond with a familiar, a creature that teaches her magic and helps to guide her along her path. Familiars also aid a witch by granting her skill bonuses, additional spells, and help with some types of magic. This functions like the Wizard’s arcane bond class feature, except as noted in the Witch’s Familiar section.

I would stick to the wording in the rule, simply because the Magus already has a feature that allows them to take spells from the wizard spell list with a specific Magus Arcana: Spell Blending (Ex):

Benefit: When a magus selects this arcana, he must select one spell from the wizard spell list that is of a magus spell level he can cast. He adds this spell to his spellbook and list of magus spells known as a magus spell of its wizard spell level. He can instead select two spells to add in this way, but both must be at least one level lower than the highest-level magus spell he can cast.

Special: A magus can select this magus arcana more than once.

Magus Arcana is a feature that a magus can exploit at level 3 and every 3 levels after that. This makes it an expensive feature, so a magus must carefully select which magus arcana to have when the time comes.

So if a magus were to select Spell Blending, they are giving up a whole bunch of other powerful features in order to learn a spell from the wizard spell list.

Such a feature should be expensive with respect to losing out on other class feature options. In other words, a feature to get wizard spells wouldn’t/shouldn’t be something that a magus could access without losing out on another class feature a magus could choose from. Even if the magus would have to undergo several Spellcraft and Knowledge (Arcana) checks and spend a lot of money, there will come a point where passing these checks and spending that money will be easier at higher levels than lower levels (the only limit would be time, which may not be possible in very time-limited portions of campaigns). In that case, the magus wouldn’t lose out on another class feature.

Let’s take an Eldritch Archer magus archetype example. A magus arcana they have access to is Arcane Accuracy (Su). But another choice they could go with is Spell Blending (Ex), as the eldritch archer had their eye on Named Bullet, a spell that is only available on the Wizard’s spell list, for a few levels now. But with a house rule where they can take a wizard spell through independent research, the Eldritch archer doesn’t need to choose between Arcane Accuracy or Spell Blending, they can have the best of both worlds at the same level. In this case, the drawback is only less time and money. That’s where the imbalance is; the magus should have to give up some feature when taking up another feature.

So to answer your question, I would think that house-ruling a magus to research spells the same way a wizard can would be unbalanced.