Fear, combined with anxiety and terror are three of the most negative human emotions. Some anthropologists have speculated, with some justification, that fear of death helps to keep our species alive.

Fear. It comes in two varieties. Fear which motivates in a positive way, and fear which paralyzes behaviour to the point of no action.

Fear of the dark and justified dangers is a universal characteristic. On a storm ravaged sea a terrified crew of a boat can be overwhelmed with fear. It is what you cannot see that can hurt you. In total darkness how close is a shoreline with precipitous submerged rocks and foaming, crashing surf? How close are we to death? If only we knew our position, and knew where were are…