Every student of spirituality should keep in mind that the limitations of the limited theories, arguments, extremisms, self-styled experts or mentors in one, two or more sciences point actually to a defective way of thinking. This defective way of thinking has prevented humans from concentrating and freeing their minds. When people are deprived of the blessings of concentration and a free mind, then doubts and evil suggestions spread like a blight in their hearts and minds. Concerning this sorrowful situation God says: “God has sealed their hearts and their ears, and their eyes are covered and for them there is a severe punishment.”