Carl Sagan IQ score is 170. In 1980, Sagan, became famous for his PBS series Cosmos, co-written with his wife Ann Duryan, wherein he defines a human as “star-stuff”; used the term "cosmic perspective" for the advanced perspective; and seemed to conjecture for a universe that is god-free, though, it seems, not stated so explicitly. 
Sagan was a self-defined agnostic; albeit leaning towards atheism in commentary; he even is commonly cited as an atheist. The following are representative position statements:

“Those who raise questions about the god hypothesis and the soul hypothesis are by no means all atheists. An atheist is someone who is certain that god does not exist, someone who has compelling evidence against the existence of God. I know of no such compelling evidence. Because God can be relegated to remote times and places and to ultimate causes, we would have to know a great deal more about the universe than we do now to be sure that no such God exists. To be certain of the existence of God and to be certain of the nonexistence of God seem to me to be the confident extremes in a subject so riddled with doubt and uncertainty as to inspire very little confidence indeed.”

— Carl Sagan (1981), interview with Edward Wakin [1]

“In science, it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.”

— Carl Sagan (1987)

Some information about Carl Sagan

With Carl Sagan IQ, it’s obvious that he was an American astronomer, astrophysicist, cosmologist, astrobiologist, author, science popularize and science communicator in astronomy and other natural sciences. He is the best known for his work as a science popularize and communicator. His best known scientific contribution is research on extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation. Sagan assembled the first physical messages sent into space: the Pioneer plaque and the Voyager Golden Record, universal messages that could potentially be understood by any extraterrestrial intelligence that might find them. Sagan argued the now accepted hypothesis that the high surface temperatures of Venus can be attributed to and calculated using the greenhouse effect.

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