There is no answer to this in the rules. I will press the FAQ button.
First, a critical hit is what happens when you roll a critical threat and then confirm it. It does not have anything to do with automatically hitting.
Second, assuming you meant critical threat, a critical threat does not automatically hit, only a natural 20 does.
Finally, just because you rolled a natural 20 does not mean you throw out all of the final number. 20+bonuses = #. If the parry attempt rolls a higher number then it is parried.
Summary: An automatic hit due to a natural 20 does not negate the total value of the roll which a parry can still attempt to beat. There is nothing in the rules stating otherwise.
RAW appears to be yes, this has been brought up before and hopefully will be clarified in the first ACG FAQ, especially since the Swashbuckler is like the new Magus in PFS, IE. everywhere.
There is no reason for it not to be possible. The same as you can still miss with a nat 20 due to concealment.
There is no reason for it not to be possible. The same as you can still miss with a nat 20 due to concealment.
Well, except they nerfed an entire feat line that allowed the same thing, one of the strong arguments was because it stopped crits.
There is no reason for it not to be possible. The same as you can still miss with a nat 20 due to concealment.Well, except they nerfed an entire feat line that allowed the same thing, one of the strong arguments was because it stopped crits.
For parry to stop that nat 20 crit the swashbuckler's roll+mods has to be higher than the attacker's 20 + bonuses. So the swashbuckler has to be a superior combatant for it to be able. That was not the case with the feat line you mentioned.
Edit: And the blur spell (as a lot of other spells) can stop crits, too. Most likely with a higher chance.