Thought is the only instrument we have. You cannot perceive what you do not know. Past knowledge comes into play to tell you how to recognize something. Knowledge is the structure. Repetition of knowledge is thought. Even the thought we are talking about is created by the knowledge that is given to us. So the thought is a self-perpetuating mechanism.
The body is not interested in that at all. The actions of the body are responses to the stimuli, and it has no separate, independent existence of its own. Unfortunately, time is the one that has created the beginning and the end, and it is interested in permanence, whereas the functioning of the body is immortal in its own way, because it has no beginning, it is not born, so it has no death. So there is a death to the thought, but not to the body. But thought does not want to come to an end. It is interested in creating an artificial immortality -- of an entity, soul, self, whatever you want to call it. It knows in a way that it is coming to an end somewhere along the line, and its survival, its continuity, its status quo depends upon the continuity of the body. But body is not in any way involved with the thought, because it has no beginning, it has no end. It is the thought that has created the two points -- this is the birth and that is the death.