We have a sense of I-ness that has remained unchanging throughout our life amidst the changing states of body and mind. That unchanging-I is the consciousness portion of the ego-I. But the ego-I does not remain in this pure consciousness form, but identifies itself with some state or the other of the body and mind, as in “I am tall” or “I am fat” etc. (in identification with the body) and “I am happy” or “I am afraid” etc. (in identification with the mind or thoughts).