Why Would Natural Selection Not Work the Same Over Interstellar Distances

"The late Czech astronomer Zdeněk Kopal summarized the pessimist outlook succinctly decades ago, in conversation with his British colleague David Whitehouse. As they were talking about contact with alien civilizations, Kopal grabbed Whitehouse by the arm and coldly said, 'Should we ever hear the space-phone ringing, for God’s sake let us not answer. We must avoid attracting attention to ourselves.'"

- From a review of/interview about the new book about the search for intelligent alien life Five Billion Years of Solitude