International Journal of Astrobiology

Intelligent life in cosmology

Frank J. Tipler a1
a1 Department of Mathematics and Department of Physics, Tulane University, New Orleans, LA 70118, USA e-mail:

Article author query
tipler f   [PubMed][Google Scholar] 


I shall present three arguments for the proposition that intelligent life is very rare in the universe. First, I shall summarize the consensus opinion of the founders of the modern synthesis (Simpson, Dobzhanski and Mayr) that the evolution of intelligent life is exceedingly improbable. Secondly, I shall develop the Fermi paradox: if they existed, they would be here. Thirdly, I shall show that if intelligent life were too common, it would use up all available resources and die out. But I shall show that the quantum mechanical principle of unitarity (actually a form of teleology!) requires intelligent life to survive to the end of time. Finally, I shall argue that, if the universe is indeed accelerating, then survival to the end of time requires that intelligent life, though rare, to have evolved several times in the visible universe. I shall argue that the acceleration is a consequence of the excess of matter over antimatter in the universe. I shall suggest experiments to test these claims.

(Received June 1 2003)
(Accepted June 22 2003)

Key Words: baryogenesis; black hole evaporation; closed universe; cosmological acceleration; extraterrestrial intelligent life; extraterrestrial prokaryotes; future of universe; teleology; unitarity.