Yah, spirits or ghosts cannot be seen by most people. But, the problem is spirits are almost everywhere like mozzies, ants, lizards or roaches. A friend of mine had such an ability. But, he said it has since faded away as he grew up into adulthood. I know of such young children who have such ability are often being scared by these things in the night. Try to avoid ground floor condo or bungalow. My mom also felt the 'chill' (a gust of moving cold 'air') in a hospital during a night visit. Remember there wasn't any windows or doorway at the enclosed corridor.