Thought and time are the roots of fear. I think I might die tomorrow: time, an interval. Or I have had pain, and I fear it might happen again: fear. This is thought projecting or reacting to what might be or what has been. So thought is the root of fear. When I go to the dentist, sit in the chair, all that drilling and pain, it is registered and projected, and I hope I will never have it again. When the drilling and pain are going on, is it possible not to register it?