The noosphere (/?no?.?sfr/; sometimes noösphere) is the sphere of human thought. The word derives from the Greek (nous "mind") and (sphaira "sphere"), in lexical analogy to "atmosphere" and "biosphere". It was introduced by Pierre Teilhard de Chardin in 1922 in his Cosmogenesis. Another possibility is the first use of the term by Édouard Le Roy (1870–1954), who together with Teilhard was listening to lectures of Vladimir Ivanovich Vernadsky at the Sorbonne. In 1936, Vernadsky accepted the idea of the noosphere in a letter to Boris Leonidovich Lichkov (though he states that the concept derives from Le Roy). Citing the work of Teilhard's biographer - Rene Cuenot - Sampson and Pitt stated that although the concept was jointly developed by all three men (Vernadsky, LeRoy, and Teilhard), Teilhard believed that he actually invented the word: "I believe, so far as one can ever tell, that the word 'noosphere' was my invention: but it was he [Le Roy] who launched it.
In the theory of Vernadsky, the noosphere is the third in a succession of phases of development of the Earth, after the geosphere (inanimate matter) and the biosphere (biological life). Just as the emergence of life fundamentally transformed the geosphere, the emergence of human cognition fundamentally transforms the biosphere. In contrast to the conceptions of the Gaia theorists, or the promoters of cyberspace, Vernadsky's noosphere emerges at the point where humankind, through the mastery of nuclear pro . . . more