There is but One Being, devoid of all qualities and beyond the pale of death, birth, decay, progress etc. It is described as Sat-chit-ananda, (Existence - knowledge - bliss).
Question yourself and learn that you are neither the body, the senses, the prana (life), nor the mind, nor avidya (ignorance). For all these are insentient while you are the Sat (the real).
The mind is nothing but the thoughts. The root thought is the little T which is known as ahamkara, or ego. When the question, 'Who am I?' preponderates , it kills all other thoughts at first and is itself gone ultimately, since the little I dwindles into nothing as you concentrate on its nature.
What is there for you to achieve while you are That (Sat-chitananda) already? You are beyond all time, space and causation. You are the Un-limited, Absolute, Supreme Being of Bliss. Like the silk worm which weaves its own web and crushes itself by being caught within its tightening folds, the ignorant man who yields to the mind and its ways seems to be immersed in a world of misery, though in reality, he never ceases to b e the One Only without a Second.