Prestige class question (Pathfinder)

[Papa Palpatine]

So I've been rolling around this idea for a while, and my DM is probably gonna let me do it anyway, but I'm curious to see if you guys think this is possible. Lets say I'm not using any early entry tricks and I take 3 levels in wizard, 3 levels in druid, and one in mystic theurge. If I then acquire two sneak attack dice and go into arcane trickster, do the levels of arcane trickster advance my spell progression in mystic theurge?

[Thomar_of_Uointer]

When a new arcane trickster level is gained, the character gains new spells per day as if she had also gained a level in a spellcasting class she belonged to before adding the prestige class. She does not, however, gain other benefits a character of that class would have gained, except for additional spells per day, spells known (if she is a spontaneous spellcaster), and an increased effective level of spellcasting. If a character had more than one spellcasting class before becoming an arcane trickster, she must decide to which class she adds the new level for purposes of determining spells per day.

Um... By a close reading, yes you do. Mystic theurge is a spellcasting class, it says you get spells per day and effective level, and it doesn't specify any limits on what kinds of spells per day nor effective level (not even arcane ones). Nice catch.

It completely violates the Rules As Intended, of course. The end result could be an extremely overpowered self-buffing polymorphing melee caster.

[watchwood]

So I've been rolling around this idea for a while, and my DM is probably gonna let me do it anyway, but I'm curious to see if you guys think this is possible. Lets say I'm not using any early entry tricks and I take 3 levels in wizard, 3 levels in druid, and one in mystic theurge. If I then acquire two sneak attack dice and go into arcane trickster, do the levels of arcane trickster advance my spell progression in mystic theurge?

No. Mystic Thurge doesn't give you spellcasting, it expands the existing spellcasting of your previous 2 classes. And since Arcane Trickster specifies that you pick a class to extend, you would have to pick either Wizard or Druid as those are your only 2 spellcasting classes.

[Keneth]

watchwood would be correct in this case. Mystic theurge has no inherent spellcasting ability, and thus cannot be advanced by arcane trickster.

[Papa Palpatine]

watchwood would be correct in this case. Mystic theurge has no inherent spellcasting ability, and thus cannot be advanced by arcane trickster.

In that case, not saying I don't agree, but how do you define "inherent spellcasting"? Also, what exactly defines a "spellcasting class"?

I ask because that wording has been bugging me for a couple of years now.

[OldTrees1]

In that case, not saying I don't agree, but how do you define "inherent spellcasting"? Also, what exactly defines a "spellcasting class"?

I ask because that wording has been bugging me for a couple of years now.

Let's pretend you cheat your way into a class without meeting any prerequisites. Does the class give you spells? If so then it is probably a spellcasting class. Otherwise it is not.

A Commoner 5 (cheating remember) / Mystic Theruge 1 cannot cast spells therefore Mystic Theruge is not a spellcasting class.

[grarrrg]

In that case, not saying I don't agree, but how do you define "inherent spellcasting"? Also, what exactly defines a "spellcasting class"?

I ask because that wording has been bugging me for a couple of years now.

There are "spellcasting classes", and there are PrC's that "advance spellcasting".
These are similar, but different things.

You can tell if it is a "spellcasting class", because it will tell you what spell list to use, what stat to use for casting, a chart with spells per day, etc...
If all it says is "+1 to existing spellcasting" then it is not a "spellcasting class".