I have always wondered why many atheists (such as Carl Sagan and Richard Dawkins) are so concerned with convincing the rest of us that God does not exist.
Correction, Carl Sagan was NOT an atheist. He was a classic agnostic. And contrary to this Fundamentalist opinion of Sagan you've described, he spent his life devoted to teaching the wonders of science, the cosmos, history, and spent very little time trying to convince anyone there was no God. He would NEVER have said such a thing, and in fact felt that atheists were "some of the silliest people" he knew. His poor widow has been debunking this urban legend (that Sagan was a hardcore atheist) for many years now. Maybe if people would just take the time to actually READ some of his books, listen to his lectures, and watch his TV programs, people would stop saying this about Sagan. He was NOT an atheist.
In fact, a lot of people say things about Dawkins that are in fact not really true either, and I used to be one of those, until I began reading his stuff. He is not nearly as vitriolic as most Christian anti-Dawkins folks are.
If there is no God, then there is no purpose or meaning other than that which we fabricate in order to assuage our nihilistic angst. So I am curious as to why a true atheist would waste their finite putrid existence on efforts to convert others to their godless faith.
Ann Druyan (Sagan's widow) told a story about how after Carl gave a lecture at a planetarium about the big bang, cosmic evolution and the like, afterwards a young man came up to him and almost in tears asked, "what am I supposed to do now that you've sucked all the meaning out of my life?" (apparently one lecture converted him from believer to atheist) Sagan paused, and then replied "go do something meaningful with your life!"
How the heck is that nihilistic? I find that many Christians, (myself included at one time) disparage atheists because of our own deep seeded doubts. Deep down WE would be nihilistic, or immoral, or see life as meaningless without God...but instead of admitting "well if there was no God I'd kill anyone I got ticked off at" we accuse atheists of having the same low moral quotient that we have. (only God keeps me moral, without God I'd be immoral, so too, all atheists must feel like ME). The problem is most atheists do NOT do immoral things, and do not live meaningless or nihilistic lives. There are plenty of stories in fact of people leaving behind faith, becoming atheists or agnostics and ending up with MORE meaning in their lives than they ever did as a believer. Why? Because they say, they realize THIS life is all we have, and we need to do our best, each day to love, laugh, help those in need, without the consolation that even if we screw up ours and everyone elses life around us, it will all be better in Heaven. (that's their reasoning anyways, whether we disagree with or not is not the point, the point is it makes sense to them)
Anyways, I only posted because lumping Sagan in with Dawkins as though they were "two of a kind" is just not accurate. Even Dawkins has said he does NOT take the Sagan approach, and he (Dawkins) has debated Lawrence Krauss (who does take the Sagan approach) as to which is the better method for science education. In fact Dawkin's is not really a science educator, but writing about religion specifically outside of the context of science, which is something I don't believe Sagan ever did.