No aliens? I want a DNA test from James Carville! :)
But seriously, thanks for posting. I will read in more detail as soon as I get a chance.
Is it possible that any society smart enough not to destroy itself would be smart enough not to construct Bracewell-von Neumann probes? I'm thinking Star Trek I here, folks.
Oh, and by the way... Once we reach step 2, I'd argue it would be fairly impossible to exterminate ourselves. The window for an intelligent race to annaihilate itself seems rather small for me. BUT! There are other means of population containment besides self-annaihilation. In certain regions of Europe, medieval civilizations avoided overpopulation by the development of a large celibate class. In England, for instance, this led to 3 centuries of peace, and life expectancies that would not again be reached until the 20th century. Fermi seems to believe that population dynamics of intelligent races mimic those of bacteria. (There are arguments for this... It takes only one dissident planet to start populating the galaxy, and this would have to take place among the outer planets -- the most likely to be dissident.)