I agree. Just because there might be a large number of stars without a habitable planet does not decrease the number of alien civilizations; it only reduces the

I agree. Just because there might be a large number of stars without a habitable planet does not decrease the number of alien civilizations; it only reduces the likelihood that a given solar system would have such a civilization. Or to put it in other words, just because the haystack is large doesn't mean there is no needle present.