Do the penalties from successive Stumbling Bash hits stack?

[JamesTheDonkey]

Basically, I found in the Magic section of the core rulebook that penalties work like bonuses, and that only the most severe of a type applies. However, it does say most untyped penalties stack.

Also, in the very start of the CRB, it describes penalties as untyped numbers that you subtract from a roll or number, and that they usually stack.

Stumbling Bash is a shield mastery feat from the Armor Master's Handbook that applies a -2 penalty to AC on victims of your shield bashes until the end of your next turn.

If I shield bash someone twice, do the penalties stack, resulting in -4 to AC until the end of my next turn?

[dragonhunterq]

Generally untyped penalties affecting the same attribute will stack with one another, but penalties from the same source usually don't (such as a feat or class ability).

So successive stumbling bashes won't reduce the AC further, but they will stack with the AC reduction from e.g.a witches evil eye hex granting -2 to AC.

[James Risner]

Nothing ever stacks from the same source except when the ability says it does or the general rules say they do (dodge bonus or circumstance bonus from different circumstances).

[CampinCarl9127]

Yup, the others are correct. Untyped bonuses/penalties stack, but not if they're from the same source.

Still a good feat. Open up with stumbling bash, then hit their lower AC with your damage dealing weapon while using power attack.

[JamesTheDonkey]

That is what I thought, but to satisfy the rules lawyer in me, which rule exactly says untyped penalties from the same source do not stack?

I know where to find that rule about bonuses, but not for penalties.

[dragonhunterq]

Back in the magic section

Combining Magic Effects wrote:

Spells that provide bonuses or penalties on attack rolls, damage rolls, saving throws, and other attributes usually do not stack with themselves.

[Claxon]

Que people saying that it only applies to spell because it's in the magic section.

In retort to that, it's general advice despite that. The same source bonuses never stack, same source penalties by extension shouldn't stack either.

It wasn't until it got FAQ'd that we established non-spell bonuses of the same type didn't stack despite it being basically establish by the spell section rules. I could see where someone might argue that it's needs an FAQ specifically, but since we have an FAQ that bonuses of the same type don't stack which was based of the spell rule that said spell bonuses of the same type didn't stack and we have a rule like that for penalties...it's easy to see that it's likely intended to work this way even if it's not explicitly spelled out.

[JamesTheDonkey]

That is perfectly fair. I just play this character in PFS so I want to be able to show where the rule is if it comes up.

The reason for my confusion is this line in the PRD that is also in the CRB:

Pathfinder Reference Document wrote:

Penalty: Penalties are numerical values that are subtracted from a check or statistical score. Penalties do not have a type and most penalties stack with one another.

It is under the common terms here. Given that at the time I couldn't find any other source, I was inclined to believe my knowledge of how penalties worked was wrong.

Thanks for clearing this up for me.

[Claxon]

Basically that line means all the different sorts of penalties stack, but what we're saying is you can't apply the same penalty multiples times because it'd be a bit unfair and if you look at other sections of the rules it leans towards agreement even though the provision don't explicitly cover non-spell penalties.

[James Risner]

Again, most penalties do stack.

Except when they come from the same source.

[Prof. Löwenzahn]

Interesting, I observed some discussions regarding self inflicting penalties and the consense was that penalties always stack.

Can't find the thread, but it was about Drunken Brawler in combination with Blade and Tankard Style, so basically drinking beer every few rounds to maintain the temporary Hit Points and boni. People said the Reflex Penalty would stack and go into infinity, which is wrong obviously?