Speaking for myself, I believe that some truth can be known by humans, but my faith is more about the ideal to strive for it. My Quaker faith speaks of "continuing revelation," particularly in contrast to originalism. But when I use the word "lying" I am very specific about an intentional act of deception. You don't have to get deep into philosophy or theology to figure that out, though there are always shades of whether the deceptive person believes their own lies.