I think there are far too many happen chances in evolutionary biology to say that an advanced civilization is inevitable; my rational mind has a LOT of trouble accepting that our current development is a long history of happen-stances beginning from life´s first development, but I see no viable alternative. But to think that given another Earth with life it would happen again? With all of the stretches that happen all along the evolutionary tree I find this absurd.
I concur. Fortunately, the Drake equation gives us separate variables for "develops life" and "develops intelligent life". The value I used for f_i was somewhat lower than they gave, but I also thought that f_c was higher, so it worked out as a wash.
