Wouldn't it be a part of perception? Perception colors truth, and so, our opinion of the truth. Like a picture of a scene. It captures a three dimensional scene in two dimensions. What it shows is the truth, for it, if not for another picture taken from elsewhere. The point of view, from where the picture was taken could be the opinion, and it would be the truth as well, but not the actual truth. The funny thing is, the actual truth can never be actually found by a 2D camera now, can it?