Do Arcanists count as spontaneous casters for magic item usage requirements?

Question

As you may know, Arcanists have a spellcasting method that is very similar to a spontaneous caster's in some areas. However, they are not considered as such. That being said, there is a line in the class description stating the following: "Feats and other effects that modify the number of spells known by a spellcaster instead affect the number of spells an arcanist can prepare.".

I wish to know whether by RAI, an arcanist can use item affecting spells known, such as a Page of Spell Knowledge, that state "being a spontaneous caster" as a requirement. It would make sense that such items, created before the introduction of the Arcanist, were written with the assumption "spells known = spontaneous caster", and thus their ability to be used by an Arcanist would depend on the specific choice of words rather than a precise intent. For instance, in the Ring of Spell Knowledge description is written:"useful only to spontaneous arcane spellcasters", which is not a requirement, thus it can be used by Arcanists. However the Page of Spell Knowledge have the wording:"If the bearer is a spontaneous spellcaster", which makes it unusable. Given the similarity between the effects I find this strange.

This point seems to be further supported by the Expanded Arcana and Expanded Preparation, since the latter is a near-perfect copy of the former, worded for Arcanists. This could indicate that the authors intended Expanded Arcana to be available to Arcanists, but unfortunately it was disallowed by RAW.

Given these points, I'd be inclined to conclude Arcanists can indeed use such item by RAI, but I would like to have the judgements of more experienced Pathfinder players and DMs.

Answer 1

Arcanists are prepared casters

Though their unique spellcasting method is similar to other spontaneous casters, like the sorcerer or oracle, the only mention about spontaneous casting is this:

Like a sorcerer, an arcanist can choose to apply any metamagic feats she knows to a prepared spell as she casts it, with the same increase in casting time (see Spontaneous Casting and Metamagic Feats).

Using the definition on the core rulebook (magic chapter, page 206):

Most spellcasters prepare spells in advance—whether from a spellbook or through prayers—while some cast spells spontaneously without preparation.

Since arcanists prepare their spells, for all purposes and rules, they are considered prepared casters. And this is evidenced again on the Expanded Preparation feat, released on the same book.

Benefit: You gain an extra spell prepared of the highest level you can currently cast as an arcanist when selecting this feat. This is in addition to the number of spells you can normally prepare from your spellbook. You can instead add two spells prepared, but both of these spells must be at least 1 level lower than the highest-level spell you can currently cast as an arcanist when selecting this feat. You must choose which benefit you gain when you take this feat, and the extra spells prepared do not change level when you gain access to higher-level spells.

But if you are looking for official answers, there is an open FAQ request thread (with 40 votes) on their messageboards.

Answer 2

Not answering the question directly whether they are considered prepared or spontaneous (they seem to be both given that they obviously prepare spells but cast them spontaneously as the prepared spells are not expanded and for metamagic effects), but specifically about Page of Spell Knowledge, the description of the class says that effects that affect known spells instead affect prepared spells from arcanist. So by RAW, I think that indicates that Ring and Page of Spell Knowledge work for arcanists.

Feats and other effects that modify the number of spells known by a spellcaster instead affect the number of spells an arcanist can prepare.

If you take the specific > general rule, the general rule for Page of Spell Knowledge is that it works for spontaneous casters, but the specific rule for arcanist prevails and given Page of Spell Knowledge modifies the number of known spells, it affects the number of spells an arcanist can prepare instead.