He passed away on 11/04 at pretty youthful 66. I knew him more from as a science fiction potboiler machine but this article in the Wall Street Journal 'Aliens Cause Global Warming' gave me new-found though posthumous respect for the scientist.
"The Drake equation (which was posited about sentient life in the universe in the first 1960 SETI conference) can have any value from "billions and billions" to zero. An expression that can mean anything means nothing. Speaking precisely, the Drake equation is literally meaningless, and has nothing to do with science. I take the hard view that science involves the creation of testable hypotheses. The Drake equation cannot be tested and therefore SETI is not science. SETI is unquestionably a religion. . . ."