Though we exist in Plato's cave, ideally we would use own constructions of magnamity or related ideas as a compass for our actions. That construction is multifaceted, but we still are limited by the lenses we wear - however golden we think they are.  

For practicality, I tend to mix the higher perspective of  *The True Ungraspable Truth* with the more local perspective of "lack of global truth", but I do recognize the nuance.