Humans are inevitably afraid of the dark.
Humans are diurnal animals, and their senses are specialized for daytime. At night, too many predators, such as numerous nocturnal feline killers, can instantly end their lives. Ancient ancestors had to rely on fire and crowds to protect themselves.
Those afraid of the dark instinctively stay close to the firelight during the deep night.
And those who are not afraid of the dark are much less likely to pass down their "fearlessness of the dark" genes.
Humans are not afraid of the darkness, but of "losing perception of their surroundings."
When humans lack information about their surroundings, they believe they are facing something or an environment that is insurmountable, uncontrollable, and unknowable. At this time, they instinctively associate it with death and life-threatening things or environments.
