Hi Brizzy & Alex,
Purity and perfected are not the same and would give slightly different connotations.
purity would give an implication of how sati is when in accompanying this Jhana, whereas perfected would imply that sati is not a seperate quality, and sammasati as a fold would not exist because it would be a part of sammasamadhi
as it is taught seperately, and within contexts outside of samadhi and Jhana the quote isn't providing reference to perfected, which I believe tilt was looking for.
just my take.
He who knows only his own side of the case knows little of that. His reasons may be good, and no one may have been able to refute them.
But if he is equally unable to refute the reasons on the opposite side, if he does not so much as know what they are, he has no ground for preferring either opinion …
He must be able to hear them from persons who actually believe them … he must know them in their most plausible and persuasive form.