eli5: Carl Sagan’s absence of evidence

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Big fan of Carl Sagan, he was like a father figure to me, I’m partially molded by him.
That said, something he used to say all the time really baffled me, still does:
“Absence of evidence is not evidence of absence”
He said this when talking about aliens.
However: Sagan was a famous non believer.
How does this aphorism reconcile with the existence or non existence of a god?
If “absence of evidence is not evidence of absence” does that apply to a god as well?
Is there a god even though there is no evidence of him/her/it?

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147 Answers

Anonymous 0 Comments

That’s no invention of Sagan’s, it’s a classical logical fallacy, the so-called argumentum ad ignorantiam.

You can think of it this way: We only recently were able to measure gravitational waves – they had been postulated long before, however. But we lacked the technological means to measure them. The absence of evidence for something may have many reasons – we didn’t look in the right place, we didn’t look in the right way, our methods aren’t sensitive enough etc.

Regarding the existence of God, the issue is rather plain: all our detection methods are depending on physics, time and space. As such, an entity supposedly existing outside time and space is fundamentally untestable. As a consequence, many scientists simply say that it’s no concern of theirs whether “God” exists or not. It’s a question that is not only currently untestable, but fundamentally beyond testing. As such, it’s not a scientific question.

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