Slippery Mind (Ex): This ability represents the rogue's ability to wriggle free from magical effects that would otherwise control or compel her. If a rogue with slippery mind is affected by an enchantment spell or effect and fails her saving throw, she can attempt it again 1 round later at the same DC. She can attempt only one additional saving throw against any given effect using this ability.
Cap of the free thinker
This soft cap helps the wearer free herself from outside influences.
When the wearer makes a saving throw against a mind-affecting effect, she can roll twice and take the better roll.
Cap of the free thinker allows you to roll twice against a mind-affecting effect and take the better roll. Slippery mind allows you to make a second saving throw against an enchantment spell or effect after the first round. Does this mean that I can roll two saving throws the first round, and if I fail both of them I can roll two more saving throws the next round?
Slippery mind stats that you only get one extra saving throw using this ability, but it seems to me that you should be able to roll that saving throw twice as per the cap.
Slippery Mind (Ex): This ability represents the rogue's ability to wriggle free from magical effects that would otherwise control or compel her. If a rogue with slippery mind is affected by an enchantment spell or effect and fails her saving throw, she can attempt it again 1 round later at the same DC. She can attempt only one additional saving throw against any given effect using this ability.
Cap of the free thinker
This soft cap helps the wearer free herself from outside influences.
When the wearer makes a saving throw against a mind-affecting effect, she can roll twice and take the better roll.Cap of the free thinker allows you to roll twice against a mind-affecting effect and take the better roll. Slippery mind allows you to make a second saving throw against an enchantment spell or effect after the first round. Does this mean that I can roll two saving throws the first round, and if I fail both of them I can roll two more saving throws the next round?
Slippery mind stats that you only get one extra saving throw using this ability, but it seems to me that you should be able to roll that saving throw twice as per the cap.
Correct.
The limitation Slippery Mind references is that you can only make the saving throw one time, not that you only get one roll. In other words, it doesn't let you use the ability every round subsequently.
Cap of the Free Thinker does not actually give you an extra saving throw, it merely allows you to roll two dice, and then you pick which result is your actual saving throw. So it would not betray the limitations that Slippery Mind lists.
Keep in mind that Cap of the Free Thinker and Slippery Mind might not be usable in tandem simply because not all Enchantment spells are Mind-Affecting Effects, and vice-versa.