We must first give their place in the mechanism of biological evolution to the special forces released by the psychic phenomenon of hominization;
Secondly, we must enlarge our approach to encompass the formation, taking place before our eyes and arising out of this factor of hominization, of a particular biological entity such as has never before existed on Earth—the growth, outside and above the biosphere, of an added planetary layer, an envelope of thinking substance, to which, for the sake of convenience and symmetry, I have given the name of the Noösphere. (From noos, mind: the terrestrial sphere of thinking substance.)