The Evolutionary Biology Lecture of the Week for August 21, 2006 is now
available at:

http://aics-research.com/lotw/

The talks center primarily around evolutionary biology, in all of its aspects:
cosmology, astronomy, planetology, geology, astrobiology, ecology, ethology,
biogeography, phylogenetics and evolutionary biology itself, and are presented
at a professional level, that of one scientist talking to another. All of the
talks were recorded live at conferences.

This is the fourteenth lecture in a summer-long series on the new science of
astrobiology.

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August 21, 2006

Part XIV: Astrobiology

Uncovering Extraterrestrial Intelligence:
When Will It Happen, and What Will We Find?

Seth Shostak

SETI Institute, Mt. View, CA

19 min.

The Drake Equation, first expressed by Frank Drake of the SETI Institute, was
intended to be used to predict the number of technological civilizations in the
Milky Way, but it's proving to be more a Rorschach inkblot test for the people
who use it.

Astronomers are in general the most optimistic when completing the equation.
Carl Sagan calculated that there may be millions of transmitting civilizations
in our galaxy sending out detectable signals at the moment. In contrast,
evolutionary biologists tend to be quite negative. Ernst Mayr famously
calculated that in all of the galaxy, we are most likely alone simply due to
the immense evolutionary improbabilities that we represent.

This negative view has become more popular in recent years with the rare Earth
hypothesis, and we have some significant evidence in supporting this view.
Enrico Fermi asked, when it was suggested to him that there should be thousands
of technological civilizations nearby, "Where are they?" That's not an
unimportant question. We have no evidence of their existence. In fact, our
evidence lies quite to the contrary.

Two questions haunt evolutionary biology: Is the evolutionary process
inherently progressive? And if it is, is technological intelligence inevitable?
Darwin and Sagan both believed that the answer to these questions was yes. The
discovery of hundreds of similar civilizations to our own elsewhere in the
universe would remove any doubt.