Absence of evidence IS evidence of absence

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I find it rather puzzling, really, that you're so willing to reach conclusions that you admit have no proof.

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Really? Then you must not be familiar with science.First, have you ever heard that "proof is for mathematics and alcohol". Any idea why people say that???Second, there are "tons" of conclusions scientists have reached without having proof (obviously) and without knowing for sure that their position was correct. One example that pops to mind immediately....for decades scientists accepted as fact that Universal expansion was slowing over time, yet they had no proof that it was. But did they know for sure that it was? Nope. In fact, somewhere around 1998 multiple evidences by two teams (at least one of which had been studying Type IA supernovae) indicated that universal expansion is doing quite the opposite: accelerating. Another that comes quickly to mind is the dispute over whale evolution: have whales descended from a mesonychian ancestor or an artiodactyl? Back in 1999 (if not still) both sides claimed to have enough evidence to show their position correct and the opposing side's wrong: note that at most, only one of those opposing groups of scientists can be correct: the other team must be wrong.If science actually had to hold off drawing conclusions until proof was discovered, as is in line with your comment, then science would come to a practical standstill.[This message has been edited by DNAunion, 11-08-2003]

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To the contrary - I assumed that you were familiar enough with science to know that by "proof" I meant what scientists mean: A sufficient weight of evidence. But, perhaps I was mistaken.

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Nice spin job. You goofed when you said PROOF, yet you try to turn it around and make me look bad. You're pretty good at playing games, I'll have to admit.***************************************

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Indeed, any thinking scholar would readily admit that an absence of evidence is evidence of absence. It is not proof of absence - but it certainly amounts to evidence. (http://www.nunki.net/PerRenput/Reaction/ReplyKitchen2.html)

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[This message has been edited by DNAunion, 11-08-2003]

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One example that pops to mind immediately....for decades scientists accepted as fact that Universal expansion was slowing over time, yet they had no proof that it was. But did they know for sure that it was? Nope. In fact, somewhere around 1998 multiple evidences by two teams (at least one of which had been studying Type IA supernovae) indicated that universal expansion is doing quite the opposite: accelerating.

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...because it was predicted by a model that, up till then, had been largely accurate in it's predictions.

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Irrelevant. As I pointed out, they neither had PROOF (the improper term you used) nor did they know for a fact they were correct: in fact, they were wrong. That's how science often times goes, and tentative conclusions abound in science.***************************************

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Indeed, any thinking scholar would readily admit that an absence of evidence is evidence of absence. It is not proof of absence - but it certainly amounts to evidence. (http://www.nunki.net/PerRenput/Reaction/ReplyKitchen2.html)

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[This message has been edited by DNAunion, 11-08-2003]

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What I find most interesting is that you've raised an example about scientists accepting a conclusion without evidence in a discussion that you started about how absence of evidence is sufficient to reject a conclusion.

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It successfully countered your statement that you brought up. That's what counts.

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Which is it, DNA? Are we to follow the model of scientists, who according to you, believe things without evidence, or your own example, who believes that an absence of evidence is sufficient to reject any proposition?

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Tsk tsk Crashfrog, back to stuffing words into my mouthBy the way, which part of the following do you state is false:**********************
For decades, scientists accepted that universal expansion was decelerating even though they had no PROOF (your improper term) that it was slowing nor did they know for sure that it was slowing.
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What I guess we'll never get you to see is that, on the question of the existence of things, a lack of evidence for the positive proposition (that the thing exists) is not evidence for the negative proposition. (There's qualifications to this that I'm willing to make, but they're not relevant here.)

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Aha. A concession, at least of sorts. Looks like even Crashfrog agrees that "absence of evidence is evidence of absence" is not necessarily one of the most fundamental logical fallacies, as someone attempted to mislabel it. (And considering that I have made it abundantly clear that my position is NOT that absence of evidence is PROOF of absence,...)

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Which is it, DNA? Are we to follow the model of scientists, who according to you, believe things without evidence, or your own example, who believes that an absence of evidence is sufficient to reject any proposition?

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Tsk tsk Crashfrog, back to stuffing words into my mouth

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By the way, which part of the following do you state is false:

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For decades, scientists accepted that universal expansion was decelerating even though they had no PROOF (your improper term) that it was slowing nor did they know for sure that it was slowing.
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The part I believe to be false about this is where you present this as a universal conclusion of scientists.

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You're dodging the actual question I see. Of course you can't simply answer my question honestly because your doing so would support my position and do harm to yours.But of course we all know that what I said is true - that for decades scientists accepted that universal expansion was decelerating even though they had no PROOF (your improper term) nor did they know for sure that it was slowing.So your childish word games - intentional manipulation of words with the goal of making it appear that I alone held a certain position, which you distorted, stuffed back in my mouth, and then implied was dubious or erroneous - fails. What I said was and is correct: I know it, you know it, and everyone else familiar with the topic knows it.

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The truth is, scientists believed that a decelerating expansion was predicted by their theories. That's a big difference between believing that it's really happening.

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Quite irrelevant regardless whether that is correct or not. I am still correct: For decades, scientists accepted that universal expansion was decelerating even though they had no PROOF (your improper term) that it was slowing nor did they know for sure that it was slowing.Here's the context.

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I find it rather puzzling, really, that you're so willing to reach conclusions that you admit have no proof.

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Really? Then you must not be familiar with science.

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First, have you ever heard that "proof is for mathematics and alcohol". Any idea why people say that???

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Second, there are "tons" of conclusions scientists have reached without having proof (obviously) and without knowing for sure that their position was correct. One example that pops to mind immediately....for decades scientists accepted as fact that Universal expansion was slowing over time, yet they had no proof that it was. But did they know for sure that it was? Nope. In fact, somewhere around 1998 multiple evidences by two teams (at least one of which had been studying Type IA supernovae) indicated that universal expansion is doing quite the opposite: accelerating. Another that comes quickly to mind is the dispute over whale evolution: have whales descended from a mesonychian ancestor or an artiodactyl? Back in 1999 (if not still) both sides claimed to have enough evidence to show their position correct and the opposing side's wrong: note that at most, only one of those opposing groups of scientists can be correct: the other team must be wrong.

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If science actually had to hold off drawing conclusions until proof was discovered, as is in line with your comment, then science would come to a practical standstill.

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[This message has been edited by DNAunion, 11-08-2003]

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That I cannot find my car keys on my kitchen table is evidence that they are absent from the kitchen table. It isn't evidence (trust me!) that they aren't in the kitchen, they're probably on the microwave. The absence only becomes meaningful when the whole picture is being looked at.

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I disagree. Looking for them in the kitchen - on the table - and not finding them there is evidence that they are not in the kitchen. It isn't proof, and the evidence may even point towards the wrong conclusion (they very well may be on the microwave), but it is one piece of evidence that supports the position that the keys are not in the kitchen.

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It is specific evidence that they are not on the kitchen table, not that they aren't in the kitchen at all.

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I still disagree (and yes I read your whole post before replying). Looking for them in the kitchen — on the table — and not finding them is one piece of evidence that supports the position that they are not in the kitchen. More below.

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So in the case that involves the entire kitchen where only one part has been searched, absence of evidence isn't evidence of absence. It is evidence of absence as regards the kitchen table, however.

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Yep, and it is also one piece of evidence that supports the position that they are not in the kitchen.

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The keys are either in the kitchen, or they aren't, they are either 100% there, or they are 100% not there. Assume there are five locations in the kitchen where they might be, the table, the drawer, on the microwave, on the shelf, or in my pocket. In eliminating the table, the keys are STILL either 100% there [I assume you mean in the kitchen], or 100% not there [I assume you mean not in the kitchen]. The probability of their existence [sic] hasn't dropped to 80%. It is a binary off/on proposition. Therefore, the fact that that they are not on the table hasn't allowed you to make any tentative conclusions as regards the likelihood that the keys are in the drawer, on the microwave, on the shelf, or in my pocket.

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I disagree. According to your above reasoning, we could search the table, and the drawer, and the microwave, and the shelf, all without finding the keys, yet we would still have NO EVIDENCE WHATSOEVER that they weren’t in the kitchen. In fact, by your reasoning, we would have NO EVIDENCE WHATSOEVER that the keys weren’t in the kitchen until were performed a COMPLETE AND EXHAUSTIVE search and failed. But by that point we’d have PROOF of absence in the kitchen. So you too are equating mere EVIDENCE with much stronger terms like PROOF or INDISPUTABLE FACT, you're just doing so implicitly. Thus, you are not addressing the position I put forward.[This message has been edited by DNAunion, 11-08-2003]

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I disagree. According to your above reasoning, we could search the table, and the drawer, and the microwave, and the shelf, all without finding the keys, yet we would still have NO EVIDENCE WHATSOEVER that they werent in the kitchen. In fact, by your reasoning, we would have NO EVIDENCE WHATSOEVER that the keys werent in the kitchen until were performed a COMPLETE AND EXHAUSTIVE search and failed. But by that point wed have PROOF of absence in the kitchen. So you too are equating mere EVIDENCE with much stronger terms like PROOF or INDISPUTABLE FACT, you're just doing so implicitly. Thus, you are not addressing the position I put forward.

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So, we've done a complete and exhaustive search of not only this universe, but all possible universes?

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Nope, which is why we don’t have PROOF of nonexistence.

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It was an early prediction of Conway's Game of Life that there would be no infinitely expansive patterns ("puffers"). None turned up during Conway's work. Should he have concluded that there were none?

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There were.

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Yeah, so? Scientists have drawn many conclusions that turned out to be wrong; science doesn’t require PROOF, despite Crashfrog’s assertion.And quite frankly, I just can't see how Crashfrog (or anyone else) can honestly say

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That's why we have the word "inconclusive", which you seem to avoid.

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I’ve been talking about we don’t know which is true, it’s not proof, it could be wrong, tentative conclusion, and other similar things throughout this thread and the other. My middle name is inconclusive! :-)I'm a fence sitter in general (until sufficient evidence has been supplied to convince me that one position is correct). Now, when someone wonders too far from the fence in a certain direction without having solid evidence to support such a deviation from "inconclusive", I try to pull them back to the fence. Perhaps you guys are misinterpreting the pull from the opposite direction as my being way over on the other side of the fence.[This message has been edited by DNAunion, 11-09-2003]

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So, then, you agree that there's no way to argue that the universe is fine-tuned for life?

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I don't agree with your logic.(1) Position X's status being inconclusive
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(2) There being no way to argue for position X
are not the same thing.In fact, if something IS CONCLUSIVE, then how could one legitimately argue about it?In fact, it is basically only the things that ARE INCONCLUSIVE that can be argued for or against.[This message has been edited by DNAunion, 11-09-2003]

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I don't agree with your logic.

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(1) Position X's status being inconclusive
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(2) There being no way to argue for position X
are not the same thing.

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In fact, if something IS CONCLUSIVE, then how could one legitimately argue about it?

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In fact, it is basically only the things that ARE INCONCLUSIVE that can be argued for or against.

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But in fact (2) is exactly what (1) means.

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Out of curiosity, do you even try to remember what was said a few messages back before blurting out your first thoughts? Please read this again.

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Another that comes quickly to mind is the dispute over whale evolution: have whales descended from a mesonychian ancestor or an artiodactyl? Back in 1999 (if not still) both sides claimed to have enough evidence to show their position correct and the opposing side's wrong: note that at most, only one of those opposing groups of scientists can be correct: the other team must be wrong.

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The ancestry of whales was still in question — it had not been settled — it was inconclusive - yet the two sides still argued for their own position. How could that possibly be true if what you stated was also true? It couldn’t be...yet it is.

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When something is inconclusive, it means that one is unable to reach a conclusion about it. How could you argue, therefore, if you cannot conclude?

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More words games < sigh >One needs to use only 1 counterexample to successfully counter the opponent’s position...What about whale evolution? Each side drew its own conclusion, yet the matter clearly wasn’t settled (at least one side had to be wrong, but which one?). So both side’s evidence was inconclusive, yet both sides drew a conclusion, and both sides argued for their position.PS: Ever hear of the term TENTATIVE conclusion? It's a conclusion that is not conclusive; some uncertainty still exists and the debate is not ended. So it is possible for something to be inconclusive and yet one can draw a conclusion about it.[This message has been edited by DNAunion, 11-14-2003]

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[A tentative conclusion is] a conclusion that is not conclusive; ...

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It's an X that's not an X?

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Who said that? Not me.

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Now who's playing word games?

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Same person as before...you.By saying "it's an X that's not an X" you are using X to represent both CONCLUSION and CONCLUSIVE. Besides the fact that one word is a noun and the other an adjective (which exposes one error in your line of reasoning), the two are NOT identical: thus a second reason your equating X with both is flawed. Let me explain that second one a bit more.If what you imply were actually true, then all conclusions would necessarily have to be conclusive. It would necessarily follow that there would be no such thing as a tentative conclusion. Yet there is such a thing as a tentative conclusion, as even you admit. Consequently, your underlying logic in your counter must be flawed.

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I thought I was saying something similar (the same? ) as DNA in this thread.

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So did I. But I guess we are both wrong on what we believe we think.

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Obviously a search of one sample in an unknown space would be pretty poor evidence to get very dogmatic on. But the point of this thread is that it *IS* evidence.

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Hmmm, that matches what I've said...well, as far as I can tell...I guess I'll have to ask Crashfrog to tell me what I think before I go saying what I think! :-)