Absence of Evidence
Absence of evidence, as they say, is not evidence of absence. Just because you can’t prove something doesn’t mean it’s not a fact. This is true, and makes perfect sense. You can’t prove you had eggs for breakfast one Tuesday six years ago, even if you did. But like all reasonable ideas, this has been abused by religious apologists seeking to justify their irrational beliefs.
They say that just because there is no evidence for their god does not mean he/she/it doesn’t exist. That is true. However, it does not justify a belief in this god either. In this sense, gods are like the Loch Ness Monster, big foot, and fair and balanced reporting of the news. All could exist, but there is no proof for any — no matter how hard people look, and how much time they spend videotaping that loch.
If you believe something just because you don’t see enough reason not to (but no reason to), ask yourself if you just believe it because you hope it’s true. If so, you have more exploring to do.
August 17th, 2007 at 11:44 am
This concept is one that has been so badly abused that I find I no longer accept it, as read. Absence of evidence is, in fact, evidence of absence - it just may not be sufficient evidence to justify acceptance of a contrary claim.
Every claim needs to be supported by evidence before belief is justified and the only situation in which we truly have absence of evidence is one where we haven’t investigated the claim at all. Any decent investigation should produce some evidence, either for the claim or against it. If the claim is one where we would expect to find X, and we don’t find X, that isn’t an absence of evidence, it’s the presence of evidence that contradicts the claim.
If the claim is that a god exists and has some effect on reality, then this effect must manifest before it can be considered real. The claim may relate to intercessory prayer or miracles. If we test intercessory prayer (and we have) and find the results are not significantly different from what we’d expect of chance (which is the case), then this is evidence that the claim isn’t true. It’s not “proof” (because we’re not talking about math) and it may not be sufficient to claim that the intercessory prayer hypothesis is completely wrong - but it’s evidence against the claim.
Similarly, consider claims about talking to the dead, dowsing, remote viewing and the various newage claims surrounding alternative healing. Do we have an absence of evidence with regard to these claims? Hardly. We have considerable evidence…and some of it might fall into the category that the believers might like to consider “absence of evidence”. In reality, it’s a matter of falsification.
Is there sufficient evidence to say “no god exists” or “all psychics are frauds”. No, and there never will be. Those sorts of absolutes don’t apply. However, when we continue to test these hypotheses and find no reason to suppose they are correct and no evidence to support them - that’s not an absence of evidence, it’s evidence against them.
While some might claim that this isn’t sufficient evidence to disbelieve the claim, my response is that they’ve managed to get it backward. We don’t believe claims until we have sufficient evidence to disbelieve them - we disbelieve claims until there’s sufficient evidence to justify belief.
Disbelief is the default position. (Not to be confused with belief in the contradictory claim…but that’s another post.)
Sagan is one of my heroes and I think he made an important point with this statement (which may not be original to him). I think he was correct in his meaning, but the wording has been abused to the point that it no longer holds that meaning. I can’t count the number of believers who have used this quote to justify their position and, as you pointed out, it’s a false justification.
August 17th, 2007 at 11:57 am
Very good points. While it’s technically true that absence of evidence is not evidence of absence, absence of evidence combined with evidence for an opposing claim means taking any action based on the possible truth of the claim is foolish.
The real problem here is that the burden lies with those making the claims — not the skeptics. It’s completely backwards that skeptics have to try to talk irrational people out of their mythology.
I have to disagree with your statement that absence of evidence is evidence of absence, based on my simple breakfast example in the article above. But I do think the ‘absence of evidence’ quote is used as a crutch by people who don’t understand what it really means more often than it is used properly.