
“You can’t convince a believer of anything; for their belief is not based on evidence, it’s based on a deep seated need to believe.”
Sometimes attributed to Contact (1985), but the quote does not appear in that book.
It appears attributed to Sagan in Judson Poling's 2003 book "Do Science and the Bible Conflict?", but without source.
Misattributed
Source: Via Google Books https://books.google.com/books?id=Ondv5WzhYYYC&pg=PA21&dq=Sagan
Help us to complete the source, original and additional information
Carl Sagan 365
American astrophysicist, cosmologist, author and science ed… 1934–1996Related quotes


“Is there anything that one couldn't believe based on faith?”
Episode 20.26: "Religions Evolve" https://www.youtube.com/watch?v=isPmxOJFy9U, Atheist Community of Austin (July 3, 2016)
The Atheist Experience

Thomas Henry Huxley. "Lectures on Evolution Title: This is Essay# 3 from" Science and Hebrew Tradition." (1882); as cited in: William Trufant Foster, (1908) Argumentation and debating, p. 55
1880s

“I believe Finland's economy is based on Moomin juice.”
Radio 2 Show (2007–2008)

“evidence is the only good reason to believe anything”
interview shown in AlJazeera https://www.youtube.com/watch?v=U0jA6VsivBE&t=0h26m04s, https://www.youtube.com/watch?v=U0jA6VsivBE&t=0h28m37s

“So, because I don’t have what I think of as superstitions, because I believe we just happen to exist, and believe in... science, evolution, whatever; I’m not as... worthy as somebody who has faith in an ancient book and a cruel, desert God?”
Source: Short fiction, The State of the Art (1991) “Piece” (p. 73)
Interviewed in the documentary series The Civil War, 1990
Context: Any understanding of this nation has to be based, and I mean really based, on an understanding of the Civil War. I believe that firmly. It defined us. The Revolution did what it did. Our involvement in European wars, beginning with the First World War, did what it did. But the Civil War defined us as what we are and it opened us to being what we became, good and bad things. And it is very necessary, if you are going to understand the American character in the twentieth century, to learn about this enormous catastrophe of the mid-nineteenth century. It was the crossroads of our being, and it was a hell of a crossroads.