From Independent People by Halldór Laxness (translated from Icelandic by J. A. Thompson):
Others believe that she lives much in the lake in the form of some kind of serpent or water-monster; and indeed it is on all men’s lips that a monster has now for many generations inhabited the lake and appeared to countless witnesses, who have testified to it upon oath, even those without second sight.
What does the highlighted phrase mean in this context? It seems to imply that witnesses were divided into those with second sight and those without. Was this ever common practice in Iceland? To what extent is Laxness alluding to historical or legendary events here?
Text added from author's comments which seem important in understanding the question:
'there is no mention of people having up-normal powers within the people "in the context" so it's not logic to assume that people without "specific powers" are testifying.'
'...the only witch in here is the women who turned to be the lake monster after death...other people are normal that is why they killed her'