The **Silence Principle** states that there are some things which are never mentioned or written down. These are things that a society assumes everyone knows, or things which are taboo to mention. Examples of taboos are: - Saying the Hebrew word for God "YHWH" - In the Arctic Circle, saying the name of an animal whilst on a hunting trip, for fear that the animal spirit would protect them. Thus, they would not say their word for bear, but would refer to "the brown one". --- The **Lethe Effect** states that this implicit knowledge will be lost over time, when the generations who know it have died, or outsiders have invaded and introduced their new culture. Using the above examples, written Hebrew did not have vowels, and so over time, people have forgotten how to pronounce YHWH. We no longer know the Indo-European word for bear, but have adopted its substitute: bruin. --- Mythologies are stories that convey real knowledge about the environment of the past. But because of the Silence Principle and the Lethe Effect, they seem to be fantastical stories that have no relation to reality. --- Reference: Barber, Elizabeth J. W., and Paul T. Barber. <i>When They Severed Earth from Sky: How the Human Mind Shapes Myth</i>. 2. print, And 1. papberback print. 2006-Kolophon: Milton Keynes, UK : Lightning Source, 2011. Princeton, NJ: Princeton University Press, 2011.