Abstract

Various forms of life have been existing on earth for hundreds of millions of years and the long history has seen the development of life from single cell organisms to invertebrates to vertebrates and to humans the truly intelli gent beings The biological organizations of various species from the lowest to the highest di er in their complexities and sizes Such di erences in internal complexity manifest in the di erences in overt behaviors and intelligence and generally speaking organizational complexities of various species are propor tionate with capabilities displayed by respective species However a gap seems to exist when one goes from high vertebrate animals to humans in that a con scious rational capacity is readily available to human beings that does not seem to be present in any other animals no matter how high they are on the evolutionary hierarchy There is a qualitative di erence Yet strange enough there is no known qualitative di erence between the biological make up of hu man brains and animal brains So the questions are Where does the di erence lie What is the key to the emergence of rational thinking and intelligence..