Let's assume someone gets the Alertness feat and a Dark Blue Rhomboïd Ioun Stone turning upon his head. Do the bonuses from both stack, to make +4 (+8 if 10 ranks) to Perception/Sense Motive checks or does this count as "twice the same source"?

If they don't stack, does the cracked version of the ioun stone stack with the feat?


2 Answers 2


The Pathfinder Roleplaying Game Core Rules says, "If a character has the same feat more than once, its benefits do not stack unless indicated otherwise in the description" (113). The feat Alertness does not indicate otherwise, so a creature already possessing the feat Alertness that sends spinning an ioun stone (dark blue rhomboid) actually has the effect of the feat Alertness twice but the benefits of the feat Alertness only once.

The competence bonus granted by either the ioun stone (cracked dark blue rhomboid) or the ioun stone (flawed dark blue rhomboid) does stack with the feat Alertness, but the two competence bonuses from both those ioun stones don't stack with each other because the bonuses have the same name—use instead only the highest competence bonus.

  • \$\begingroup\$ From where do you see the dark blue rhomboid give a competence bonus ? I can't find it. \$\endgroup\$ Commented Jun 27, 2016 at 15:59
  • \$\begingroup\$ @AnneAunyme While the typical stone grants the feat Alertness, the cracked and flawed stones each grant a competence bonus instead. \$\endgroup\$ Commented Jun 27, 2016 at 16:03
  • \$\begingroup\$ Are you really sure granting "the effects of the Alertness feat" is the same as "granting the Alertness feat"? \$\endgroup\$ Commented Jun 28, 2016 at 7:32
  • \$\begingroup\$ @AnneAunyme Nope. I had made a technical error and later corrected it (that's the edit I made where it says edited XX hours ago). Although gaining a feat's effect is a lot like gaining the feat, technically gaining the effect of a feat is not gaining the feat. But, since actually having a feat also means also having that feat's effect, having both the feat proper and the same feat's effect separately is, often, just as pointless. \$\endgroup\$ Commented Jun 28, 2016 at 8:15

tl;dr - Alertness does not stack with the dark blue rhomboid stone, but does stack with the cracked version.

How Bonuses Stack

The important aspect of bonus types is that two bonuses of the same type don't generally stack... Bonuses without a type always stack, unless they are from the same source.

Source: d20pfsrd

Dark Blue Rhomboid Ioun Stone: No

The stone grants the user the Alertness feat. It does not stack with the Alertness feat, because these are both from the same source (Alertness).

Cracked Ioun Stone: Yes

The cracked version of the stone does not grant Alertness, it grants a competence bonus. Alertness may stack with this bonus because they come from two different sources. The key here is that the types of the bonuses need to be different. Because the bonuses are of different types, they stack.

  • \$\begingroup\$ Technically the ioun stone don't grand the feat, it grants "the effects of the feat". Are they still the same source ? \$\endgroup\$ Commented Jun 27, 2016 at 15:38
  • 2
    \$\begingroup\$ Yes. Having the feat and having the effects of the feat only differ in that the "effects" version doesn't satisfy prereqs for other feats. \$\endgroup\$
    – GreySage
    Commented Jun 27, 2016 at 16:06
  • \$\begingroup\$ @GreySage That would be a really useful thing to cite. \$\endgroup\$ Commented Jun 27, 2016 at 17:30

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