The sense of my own existence is always there. And it's there effortlessly to use memory. We are so confident of our own existence we don't worry about it. But this constant, ever available, effortlessly available existence is a very limited existence because we mix it up with the body. I am not very sure that i existed before the birth of the body. It subject to aging. The body is becoming more and more difficult and miserable. When you check i exist, do you first check the body? No, in your dream also you can check whether i exist. There the actual physical body is lying asleep, and you are not aware of it. Still, you will get the sense