Like light, we take health for granted. It is only when the two are gone and the accompanying manifestations of a lack of light or health are evident, that we begin to act. Unfortunately, it is usually in the direction of alleviating the manifestations of that lack of health, instead of addressing the cause of it or working to restore the lost health. The inability to move about confidently without harm is one. Granted, we may treat the effects because our spouse is sound asleep, but we recognize that the better approach is to turn on the light.
Fear is another manifestation of the darkness.
A small child will be afraid of the dark at bedtime. It is an unfounded fear. You can explain to the child that he or she is a safe as could be tucked in bed, but reason is usually not a satisfactory method of dealing with the child's fears. A 7.5-watt night light is invariably the answer. A small little bulb fills the void with sufficient light to dispel the manifestations of a lack of light and its symptom, the fear.