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?
In: 95
Here is an example. There is either an even or an odd number of stars in the galaxy, but we do not have evidence that there is an even number of stars in the galaxy. But the fact that we lack evidence that there is an even number of stars is not itself evidence that there is an odd number of stars.
Here is a suggestion about when some fact f is evidence for a claim c. Some fact f is evidence for a claim c when, if we assume that c is true, the probability that f occurs is p1, and if we assume that c is false, the probability that f occurs is p2, and p1>p2. In other words, f is more likely given that c is true than it is given that c is false, and that is why f is evidence in favor of c.
Hopefully my example about the number of stars in the galaxy demonstrates Sagan’s idea that the lack evidence for c is not necessarily itself evidence that ~c. (~c means ‘it is not the case that c’ or ‘c is false’). This idea seems correct because there are cases where you lack evidence for c, but the likelihood that <you would lack evidence for c> given that <c is true> is just as high as the likelihood that <you would lack evidence for c> given that <c is false>. Because <your lacking evidence for c> is just as likely on the assumption that c is true as it is on the assumption that c is false, <your lacking evidence for c> does not raise or lower the probability that c is true.
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