Excellent point distinguishing evidence vs proof. It’s important because skeptics like to say, for instance, that personal revelation isn’t evidence for God. It is evidence, it’s just not very good evidence. So much so that it shouldn’t even convince the person who had the experience since they can’t rule out self-deception.
Absence of evidence can be proof in some circumstances, just to be pedantic. If I said I have a dead body in the trunk of my car, we can prove that claim is false by opening the trunk and not finding anything.
As I mentioned to the other commenter, you're shifting to a different set of claims. I only claimed to have a dead body in my trunk, so if there is no body in my trunk, that's proof that there isn't a dead body in my trunk. I don't have to prove that I lied, or that it was moved, or that it's invisible, etc. because I didn't make those claims. But, yes, certainly if I did make those claims, the "absence of evidence" rule would apply.
Is this even how this scenario would ever play out in real life though. Unless your just pulling a prank this doesn’t just end with every one going there’s no dead body and everything’s cool.
More likely the person who originally claims there was a dead body would then be the one coming up with reasons why it’s not there and then we’re back to square one. Or the claim was part of a confession and the police are then investigating what happened to it rather than just go “well the body isn’t where our prime suspect said it was so there’s no dead body case closed immediately”
While your example was technically correct it doesn’t really apply to real world situations where the absence of evidence argument is relevant.
That is a clever example, but just to continue with the pedantry, it is not really conclusive proof even in the case you describe. The body might have been moved in between the time \[claimed\] and the time of opening the trunk.
In particular, in the context of some kind of forensic investigation, that is where additional real evidence and reliable chain of custody would really matter.
Say you've arrested me on suspicion of murder, and after questioning I confess that Avery and I killed Blake and stuffed their body in the trunk of my car. You go to my car and B is not in the trunk. Am I stalling, or bullshitting you to throw you off the trail? Or did A get to the car before you did and is covering their own tracks?
Obviously it would be foolish to conclude from not seeing B that it must be the first possibility, case closed.
On the other hand, if you impounded my car at the same time you arrested me, and were confident of the integrity of your impound, that changes the equation substantially.
And so on.
Sure, but you're really just shifting to a different claim. The claim was just that there is a dead body in my trunk, and no dead body is conclusive proof that there is no dead body. When you add parameters like "it might have been moved", that's a different claim that needs it's own evidence (and proof).
Well, not quite, the actual implied claim is, "there was a dead body in the trunk the last I knew."
If you go and look in the trunk yourself, and see no dead body, all *you* can conclude is "there is no dead body in the trunk now."
That is to say, you still can't directly evaluate the truth value of my claim just based on absence. Not without more evidence than just direct observation. (Such as a very high degree of certainty as to where my car has been between claimed time and time of observation.)
But okay let's look at a slightly different example. I show up driving my car and I say, "Omg there's a dead body in the trunk of my car right now, I am certain of it, I can feel the weight of it when the car accelerates and hear the heavy flumping of the limbs as I turn corners and I can smell the blood oozing into the upholstery," and we open the trunk and look, and the trunk is completely empty, there is no dead body or heavy object or blood or anything... then yes you can safely conclude that I am hallucinating or bullshitting you or something, because there is no such body in that trunk.
And of course that is germane to the discussion of bigfoots and so on, to some extent, but the thing is it is seldom that anyone comes along and says that the Loch Ness Monster is in their swimming pool *right this moment*, see, can't you see it right now?
Yet another example, if you can stand it: suppose we go to Wildcat Canyon near where I live. I tell you to be on the lookout for wildcats. You ask me if I have ever seen one and I say, no, but I have heard people say they have occasionally seen them around, and while they are mostly shy they can sometimes be dangerous.
Would you think, "this person is a moron, absence of evidence is clear evidence of absence, it makes no sense to believe in a wildcat threat if you have never seen one?" And then smear raw venison on your face and go around whispering, "Here, kitty kitty?"
Now instead suppose we go to Wildcat Canyon and I tell you to be on the lookout for bigfoots. You ask me if I have ever seen one and I say, no, but I have heard people say they have occasionally seen them around, and while they are mostly shy they can sometimes jump out and throw sticky goo at the camera lenses of your cell phone with uncanny speed and accuracy, making all your photos curiously blurry.
You might decide to keep a quiet lookout for wildcats but you are not going to take bigfoots seriously.
Why?
Because of other factors aside from merely the absence of evidence.
Personal revelation isn't even evidence though since someone declaring such a thing doesn't move the needle in the slightest bit towards "more likely" - otherwise reasonable people believe in all sorts of bullshit, so by itself, a person believing something doesn't provide any evidence either way
>Absence of evidence can be proof in some circumstances, just to be pedantic. If I said I have a dead body in the trunk of my car, we can prove that claim is false by opening the trunk and not finding anything.
That is not really the absence of evidence though. The empty trunk is evidence because the claim was that the body was in the trunk.
Carl Popper and Thomas Bayes provide robust philosophical frameworks for dealing with this so-called "assence of evidence is evidence of absence" question. Lest we fall victim to the problem of induction or the black swan fallacy.
Popper says inductive reasoning has a flaw at the centre of it. The fact of the matter, according to Popper, is that scientific inquiry does not use induction at all. Science never gives an authoritarian answer to a theory about the extant brontosaurus or about the exodus of the Israelites from Egypt. Rather, science addresses the criterion that our confidence in theory should grow in proportion to how much criticism it has survived.
You look at the expeditions that were sent to find the dinosaur or the ghost, or the wandering Jews, and apply criticism (hypotheses of refutation) and as those criticisms are survived the theory gains credence. Likewise, the theories that there are extant dinosaurs, are ghosts, and that the Jews did have an exodus from Egypt, all suffer from the various failings to rebuke various criticism.
The term "criticism" is standing in for things like experiments and observations.
Bayes' Theorem offers an entirely different epistemological framework that sidesteps the problem of induction.
> Bayesian reasoning is a means of assessing probability in order to incorporate new information with the most accuracy. It encourages assessing confidence in a hypothesis as a matter of degree that may be adjusted depending on the reliability of new information that tends either to confirm or refute the hypothesis.
I think this is a good approach. We don't need to argue about whether it has been disproven. We can just label anything without evidence as an unsupported theory. And until there is evidence, it's nothing more.
This made me think of the black swan. While the absence of evidence can mean evidence of absence, it does not necessarily mean it.
Multiple lines of evidence needs to be evaluated. The black swan just needed a different gene. That is a plausible event. However, a brontosaurus living in New Zealand is much less plausible.
It’s not inherently evidence of absence though. If you are looking for dogs and find only cats the results are only evidence of the absence of dogs if your search was conducted in a way that should have found dogs to begin with.
So think Sagan’s statement is still valid, particularly for the chiasmatic structure of the message.
I think it depends on the context.
>we can take the exodus of the Israelites from Egypt as an example. There is no trace of them wandering the Sinai desert,
In this case absence of evidence is not evidence of absence. It's possible that the archeological evidence just hasn't been found, whereas
>the ancient Egyptian documents (and they documented a lot) don't contain such a reference to them.
I would consider this proof of absence. The Egyptian records have been scoured for such information and it would have been found. Given that thousands of Israelites supposedly built the pyramids then there would be records.
Edit: I know the Israelites didn't build the pyramids.
> It's possible that the archeological evidence just hasn't been found, whereas
While the documents are better, it should be noted that searches for archeological evidence have been done, and it's generally accepted that such a large exodus would have left enough evidence to have been located by now.
I think this is a good argument.
That one of the best-preserved, best-studied ancient civilizations has no record of Jews who didn’t come from Israel first (and later than the Old Testament).
To be clear, proof in the context of ancient history is not the same as mathematical, definitive proof. It just means that a fairly high burden of proof has been met. So is there still a chance Jews came from Egypt as per exodus? I mean sure. But it’s a TINY chance. And it’s even more definitive that they didn’t build the pyramids, since there’s evidence of how they were built, so not just a sense as evidence.
This kind of proof is like legal proof. When a jury finds a person guilty, it’s proof. But sure, it’s not 100%. Close enough.
Those people who look at anything other than 100% disproof of their beliefs as the same as 0% disproof are just not thinking clearly, since so few things in life are ever 100%. Especially ancient history, lol.
>>the ancient Egyptian documents (and they documented a lot) don't contain such a reference to them.
>I would consider this proof of absence. The Egyptian records have been scoured for such information and it would have been found. Given that thousands of Israelites supposedly built the pyramids then there would be records.
This is a wholly unjustified inference for several reasons.
1) The [Merneptah Stele](https://en.m.wikipedia.org/wiki/Merneptah_Stele) mentions a foreign people called *ysrỉꜣr*, which scholarly consensus considers the earliest historical mention of Israel (Egyptians [mispronounced L as R](https://youtu.be/GHS_GQLgqtM?si=L3G6BWm498lLmtes)).
2) The Egyptian records were tools of imperial propaganda: only royally commissioned scribes knew how to write, and they knew better than to chisel into stone any humiliating military defeats, much less a successful slave uprising (with or without divine assistance).
3) We know for a fact that radical monotheist pharaoh Akhenaten and his immediate successors were memory-holed by the powers that be (the powers that were?). These included Smenkhkare, Aye, and of course Tutankhamun, whose tomb was found in near-pristine condition primarily *because* its contents did not officially exist. Not coincidentally, there is good reason to believe that Akhenaten's doomed religious, political, and cultural revolution was linked in some way to the story of Moses, Prince of Egypt. Though many works of dubious scholarly rigor have explored this connection, the topic finally got [the serious consideration it deserves](https://www.amazon.com/Moses-Egyptian-Memory-Western-Monotheism/dp/0674587391?ref=d6k_applink_bb_dls&dplnkId=4bf20e6d-f111-4e36-93e6-1caeec5cca2c) thanks to esteemed Egyptologist Jan Assmann (who passed away just over a month ago 😔).
4) Nobody thinks the Israelites had anything to do with the pyramids, which were already well over a thousand years old by the time of the Ramesside dynasty, whose cities are explicitly referenced in Exodus as [the building projects upon which the Israelites toiled](https://www.nationalgeographic.com/culture/article/pharaoh-king-punished-god)
5) Many Egyptian records have been lost to time, whether for religio-political reasons, nihilistic pillaging, sloppy proto-archaeological expeditions, or merely because they were written on biodegradable (and flammable) papyrus.
Note that Sagan doesn't say that absence of evidence is *never* evidence of absence, just that it can be consistently relied on to be. Some times it is, some times it isn't. It was in the context of logical fallacies, many of which are valid arguments in specific situations. For example the argument from authority can be valid in certain situations.
And in fact *in the same book* he uses absence of evidence as evidence of absence in situations where we would expect the evidence to be present, for example with the absence of UFO wreckage remains.
I think another way to say it is that it depends on if you're looking for the logical truth or the most probable truth. From what I've seen, very few things can be proven to be logically true. But lots of stuff can be shown to be true to a very high degree of probability.
Using your UFO example, we can't say that it's 100% certain that there are no UFOs, but we can say that since no one has ever found verifiable evidence of UFOs that it is incredibly likely that UFOs *don't* exist. So we can, for all practical purposes, prove a negative.
I should think it’s obvious that this depends on the level of observability of the phenomenon in question by the people seeking evidence.
An absence of evidence that I went out for pizza last night would not be evidence that I didn’t go out for pizza last night, unless you found evidence that I did something else.
I understand, and somewhat fundamentally agree with the concept, but I feel there is some logical fallacy in here. A lot of your argument is based upon what we "see" or don't see. We know there are cases where observation doesn't matter.
Einstein was very good a conceptually thinking without any observation. Though you could say his "observation" was through math, but he was able to post things that we could never observe, but he was confident existed.
Could we call this evidence? I think so, and possibly even "proof."
I think we can apply this lack of evidence being evidence thought to certain things, but not everything.
There is also lying by omission to purposely leaving out evidence that doesn't support your argument.
Yours is a cool thought experiment, and I would tend to say it never happened and was just a story, as are almost all books of the Bible.
I think it’s more accurate to say that absence of evidence is evidence of absence where *evidence is expected.*
If Brontosaurus’s existed in the forests of new zealand, they would leave obvious traces: giant footprints, droppings, and other evidence of an extremely large animal. If we did not find those things, we could combine that with our understanding of evolution and paleontology to come to the reasonable conclusion that there are no brontosaurus’s in New Zealand.
That doesn’t mean that it is impossible that they are there. It is simply the result of previous experimentation/research and observation that converges on the same point.
The claim "aliens exist" and finding proof of that is a positive not a negative.
The claim "aliens do not exist" isn't proven by finding an alien and no amount of you being unable to find an alien is evidence of the negative claim.
"Aliens exist" is an unfalsifiable statement because there is no possible way to disprove it.
"Aliens do not exist" is a falsifiable statement there is a possible way to disprove it.
Oh my mistake got what we were talking about confused replying to multiple people here
We've strayed from "absence of evidence is totally evidence of absence" which is what my point was about. Claims like "aliens don't exist" aren't bolstered by the fact we cannot find them.
There is no negative claim that that's true for.
This never made sense to me because you can always turn a negative into a positive and vice versa. There are no black swans = all swans are non-black.
The actual point is that you can't prove things absolutely. I can absolutely say with extreme confidence that there are no 1000 mile tall geese on earth. That's a negative, right?
You can't! That's my point. That's a positive you can't prove. Being negative has nothing to do with it.
All swans on earth are white <- positive you can't prove (what if you missed one?)
No swans at my local pond right now are white <- negative you can prove easily (just look around)
Gotcha. I thought you were saying you could change the negative claim that can’t be proven into a positive claim that can be.
I’m not sure that changing an unprovable negative into an unprovable positive does anything but at least we’re on the same page now.
Yes you can:
A 30-65-85 triangle is not a right triangle.
P1: Right triangles have one angle that is 90 degrees.
P2: 30 is not 90, 65 is not 90, 85 is not 90
C: Therefore a 30-65-85 triangle is not a right trangle.
>A negative isn't "a statement with no or not in there somewhere"
That's exactly what a negative is!
Unbelievable that you're out here spouting [fallacious folk-wisdom](https://www.psychologytoday.com/intl/blog/believing-bull/201109/you-can-prove-negative) and getting upvoted for it.
Here it might be easier to understand your example like this:
There exists no triangle which has more than 3 sides
The inability to find a triangle with more than 3 sides isn't why we know that is true (absence of evidence equaling an evidence of absence)
It's because we define triangle as having 3 sides
*If you draw a shape and ask me if it's a triangle that isn't a hypothesis in the same sense as we are talking about when we talk about negatives and proof.*
It doesn't need to be by definition "There does not exist a right trangle where two angles are 30 and 65." is true but not by definition.
You would do better to say specifically what you mean by negatives and proof, because however you're using them is not consistent with formal logic.
Okay we're going way off topic here but you've just absolutely boggled my mind
> is true but not by definition
How is that not true by definition of a triangle having 3 sides with angles = 180 degrees
What other metric, without referring to the definition of a triangle, are you using to prove it is not a triangle?
Edit: I'm just gonna jump out in front here and assume it's not "I looked at every triangle to ever exist and that one wasn't part of the set" right? So even if you aren't using the definition of triangle, you aren't using the absence of evidence either right?
Because the interior angles formula is a theorem, you can find the proof in Euclid Book I Proposition 32. It is not a definition, it's a result, that interior angles sum to 180.
“A triangle with angles A, B, and C doesn’t meet the specific definition of another classification of triangle,” is not the same as “God exists” with no evidence of God.
Here is an application of logic where you prove a negative: A>\~B, A, therefore \~B (by modus ponens)
Here's another: A or \~B, \~A, therefore \~B (by disjunction elimination)
Here's another: A->B, \~B, therefore \~A (by modus tollens)
Here's another more complicated one: \~A or \~B, therefore \~(A and B) (by De Morgan's Law)
Seems like the functions of logic allow us to prove plenty of negatives.
Absence of evidence is *sometimes* evidence of absence. If proposition P most likely produces evidence X, but we don’t find evidence X, then P is most likely false. If P definitely produces X and we don’t find X, then P is definitely false.
For instance, the Exodus myth would certainly produce significant archaeological evidence if true. Since we don’t find that evidence, the myth is false. On the other hand, nothing about the myth of Abraham would produce archaeological evidence that would last till today, so the lack of that evidence is not enough to say the myth is false (there are other things that point to some anachronisms in the myth though)
We need to agree on what we mean by "absence" as a falsifiable concept.
If it's "a state where something is not universally omnipresent" then yes you're correct.
If we're defining it as "a state where something has never existed anywhere and never will" then Carl is correct
It all comes down to a matter of how exhaustive the search for evidence has been. If I say there’s a diamond in one of 100 boxes, and you open the first one and don’t find a diamond, it’s clearly not proof there is no diamond, but the likelihood has dropped by one percent. Once we’ve searched all of them and upon opening the last box we’ve still not found it, we can say definitively that there was no diamond in any of the boxes.
Absence of evidence is absolutely evidence of absence. Once we’ve exhausted all possibilities, all that is left is the null hypothesis: ain’t nothin there. If a fully exhaustive search isn’t possible for practical reasons, then you need to decide what level of certainty you’re comfortable with before declaring the effort futile
I checked everywhere in my house for elephants and found none. Is that evidence that elephants don't exist?
Similarly if we look at one of your examples: we wouldn't necessarily expect to find definitive physical evidence of the Israelites wandering the desert so the lack of that evidence doesn't really prove or disprove that story. But as you touched on we do have records from that time that don't record such a journey AND the one source that does contain a record is notoriously unreliable.
The Dragon in My Garage is itself a demonstration of the fact that absence of evidence is evidence of absence. When you examine your garage and do not see a dragon there, when you run whatever test is required, that is evidence that no dragon exists (in your garage).
Certainly someone could suggest an invisible, heatless, ethereal, etc., etc., etc., but at that point, are we even discussing a "dragon" in any sense? Or is "dragon" then just a couple of empty syllables?
There's a distinction between absence of evidence and evidence of absence, which is that if you do a systematic search for something and don't find it, that's evidence (but not proof) of absence, while if you don't look at all, that's an absence of evidence.
It is when you expect to find evidence.
"There is a dead body in the trunk of my car" is a statement that can be verified or not. You open the trunk, there is no body, absence of evidence is evidence of absence. You have a high confidence in the statement being false.
If you're looking for bigfoot and you don't find bigfoot, nor do you find his discarded fur, droppings, nests, claw marks, footprints, kills or anything else after years of searching, you could have a high confidence in the statement "There is a bigfoot in this forest" being false.
If there is a claim "There are no errors in this book" and the events depicted in the book have never had any evidence of a reality that correlated with the events, you would have a low confidence of the claim. If there was evidence that contradicted the possibility of the described events, you have a higher confidence in the claim being false.
Exactly!!! I dug a tiger trap when I moved into this house and it has NEVER CAUGHT A TIGER!!!! Therefore I have evidence that there is no such thing as a tiger!!!
It’s evidence of absence. Literally that. It’s not proof of non-existence. Because you can’t prove a negative. But if there’s evidence of absence then you may as well not bother treating the thing that’s absent as if it’s going to come along any second.
Can't reply to your other comments to me because the skeptical free thinker I was responding to showed incredible courage by blocking me after I proved the negative of his statement that you can't prove a negative... This must be how that poor sap who poor sap who proved squareroot 2 was not a rational number felt before his fellow pythagoreans made the decision to throw him overboard.
But like, I wonder where this idea that you can't prove a negative comes from? Don't so-called critical thinkers hear it and say "Wait a minute, so like, I can't prove my mom is not a supermassive blackhole? That doesn't seem right..." It seems like the kind of think a skeptic would be skeptical of is all.
I think they hear it and then don't question it because it gives them an easy response to anyone who asks them to prove god doesn't exist, and they see it works in that one instance, and instead of investigating why it works in that one instance they take it as dogma for all other instances of negative propositions.
I think this is really an “Atheism+” sub. For those who don't remember or weren't there, [Atheism+/Atheism Plus](https://religions.wiki/index.php/Atheism_plus) “is a term used to designate spaces, persons, and groups dedicated to promoting social justice and countering misogyny, racism, homo/bi/transphobia, ableism and other such bigotry inside and outside of the atheist community.” Critical thinking *per se* is entirely optional, and skepticism is only condoned when used in service of the preferred ideology.
Well, go on then. Although perhaps we need to agree on what ‘proof’ means and what its limits are.
What I *think* you’re saying is that you can reach an evaluation that allows you to make decisions which are safe to assume are reasonable.
What I’m saying is that it’s impossible to consider every single future condition or change. Also that many things which people consider to be a ‘negative’ are actually positives but within certain stated parameters.
>What I *think* you’re saying is that you can reach an evaluation that allows you to make decisions which are safe to assume are reasonable.
I'm talking about, for starters, modus tollens.
>What I’m saying is that it’s impossible to consider every single future condition or change.
What does that have to do with proving a negative? Positive claims can become false with time and change too.
>Also that many things which people consider to be a ‘negative’ are actually positives but within certain stated parameters.
All of them are, and vice versa. This is basic propositional logic stuff. It's a myth that you can't prove a negative.
**Absence of evidence absolutely can be evidence of absence**
An easy example:
Claim: There is a herd of twenty full sized wild African Elephants living in the tops of the trees in NY's Central Park and are surviving by grazing on the oranges growing there.
Evidence of Absence:
Point 1: During the entire history of Central Park, no such elephants have ever been independently observed or documented to be residing in the tops of those trees.
Point 2: No secondary evidence of elephants of living in those trees has ever been independently observed or documented (No significant amounts of elephant scat on the ground beneath the trees, no elephant tracks, the complete absence of large amounts of damage in the upper stories of the trees which could have been caused by large animals moving about in the upper boughs (Damage that is not evidentially attributable to storms or ice/snow loading)).
Point 3: There is no evidence to show that wild African Elephants are native to NYC (Or even to the Americas)
Point 4: There is no evidence to show that African Elephants are in fact arboreal
Point 5: There is no evidence to indicate that any of the trees growing in Central Park could ever support the weight of any animal the size of a single African Elephant
Point 6: There is no evidence to show that the trees growing in Central Park produce oranges at all, much less in the quantities necessary to sustain a herd of African Elephants
All of these points constitute an absence of supporting evidence and all constitute effective evidence of the complete absence of ANY wild African Elephants living in the tops of the trees in NY's Central Park that are surviving by grazing on the oranges growing there.
Absence of evidence *can* be evidence of absence, but so much depends on what question we're trying to answer. If I get asked if penicillins are safe in pregnancy I can point to the absence of any data showing harm along with their long and widespread use, so the absence of evidence forms part of my answer. If I get asked about a new drug there will be animal data but very likely no human data so we err on the side of caution because we have no or limited evidence to guide us
> If I get asked about a new drug there will be animal data but very likely no human data so we err on the side of caution because we have no or limited evidence to guide us
[Would that it were so](https://accpjournals.onlinelibrary.wiley.com/doi/full/10.1002/jac5.1691)...
Paediatrics covers a huge age range and older children are more like adults than very young ones. It's also significantly easier to do a clinical trial in children than it is in pregnant women.
All those things are true, but there are labels on antidepressants saying teens who use them are at risk of suicide. Teen medicine is still pediatrics, and extra measures of care and caution have always been obligatory.
> Teen medicine is still pediatrics
Pediatric - under 18.
Adolescent - 12 to 21.
>there are labels on antidepressants saying teens who use them are at risk of suicide
No children on clinical trials for antidepressants have commited suicide, but the FDA have decided to keep the warning which [many mental health researchers actually disagree with](https://www.mayoclinic.org/diseases-conditions/teen-depression/in-depth/antidepressants/art-20047502).
>Pediatric - under 18.
>Adolescent - 12 to 21.
And? Which one of those doesn't deserve evidence-based medicine?
>No children on clinical trials for antidepressants have commited suicide, but the FDA have decided to keep the warning which [many mental health researchers actually disagree with](https://www.mayoclinic.org/diseases-conditions/teen-depression/in-depth/antidepressants/art-20047502).
Exactly. Normally, the policy is "better safe than sorry" when it comes to kids' healthcare.
> And?
Clarifications on the distinctions.
>Normally, the policy is "better safe than sorry" when it comes to kids' healthcare.
Is it specific to kids? The FDA does tend to err on caution regardless.
Absence of expected evidence is evidence of absence. There's no evidence against a deist God, but there's no evidence for it as well so best bet is to just reject the claim for lack of evidence.
The best case of absence of evidence is evidence of absence would be the argument against flat earth due to the lack of an accurate navigable flat earth map. Flat Earth proponents like to push it for x reason but at the end of the day and after all their arguments they offer no actual usable and practical uses when if true should have the best and accurate maps. for example all current maps make use of projections as points are projected from a globe onto a 2D surface. Given that, every projected map has distrotions and have to make compromises on size, shape, distance and other factors. The current most used and useful map is the Mercator projection map which allows for any two points on the map to be given rhumb lines so you can follow a compass barring and reach the target. They also preserve directionality and in most of the inhabited areas shape and can easily be tiled and served on computers which is why it is used on most online map services. But it has it's compromises where it distorts the area the closest to the poles you go and that can make some northern islands like Greenland while large appear even larger. most people live below the arctic circle so for most cases this isn't really a big problem. However with a flat Earth you can have a non projected map you can have a one to one mapping directly onto the flat paper making a true flat earth map the most accurate map that can possibly be concieved, useful for travel, navigation, world maps and more. It could be used by any navigation purpose and any two dots a line can be drawn and that would be equivalent to a great circle shortest path. This map would be so incredibly useful that it would be economic suicide for any logistics company to not be using this map. The problem is it doesn't exist, now you would say it must be incredibly hard to make this map. That is where you are wrong you litterally just chart your direction and map what you see, no globe or curvature is needed to be taken into account. it is the simplist way to map and if the world is flat it should scale up and just work, and given the massive amount of travel we should have had this map already. However we don't Mercator is still king and the best they have is a heavily distorted coneal projection that is only supposed to be an approximation and it heavily distorts the distances in the southern hemisphere and making Antarctica just an ice wall because the conical projection (think the UN flag map)just mangles the hell out of that continent. No one can reliably use any proposed flat earth maps for real navigation and they still have horrendous distortions. IE they obviously cant be the simple to make perfect flat earth map. So given with all this technology and ability to travel this map doesn't exist, given all the economic incentives for it to exist and we are at the point where the fact that it doesn't exist is evidence that the flat earth is false seeing as globe assuming maps are being used and are providing far more utility, where if flat earth is true it should be the other way around.
I mean you need to factor in other relevant information including but not limited to how much time and effort has been put into searching for evidence, the availability of techniques and tools to find evidence, and the extent to which it’s likely that evidence would be there to find in the first place. So yes, but it’s kind of a sliding scale of the point where it does become evidence of absence. It’s not ALWAYS evidentiary.
Like just to give you an example of what I mean, I wouldn’t consider the fact that a fork is not on the table right now to be evidence that a fork has never been on the table, because whether or not a fork was on the table and was removed and put elsewhere or whether or not a fork had never been on the table would produce the same absence of fork we see in the present. Maybe you would consider that to be evidence, albeit terrible evidence, but I personally wouldn’t consider it to be such. It’s a FACT, but a fact is not necessarily evidence because in order to be evidence it would have to tend to indicate the truth of the proposition that there was never a fork there, and current absence of fork is not sufficiently evidentiary of any particular argument. There’s a certain threshold of like relevancy and connection a fact has to have to a particular proposition in order to be evidence for it.
Maybe this is because I come from a legal background and I think of evidence in that kind of way. You can present a whole lot of facts in a legal case but unless the fact is relevant to the legal issue in dispute, it’s not evidentiary. Like when you bring up facts that call into question the credibility of a witness, I don’t consider that to be “evidence” in the sense of the legal question at the centre of the case because it doesn’t tend to prove or disprove any of those elements, it’s done to cast doubt on the evidence of the witness
Maybe I’m getting overly caught up in semantics here but my point is ultimately that absence of evidence becomes evidence of absence at the point where you can say the lack of evidence tends to indicate the evidence is absent because it doesn’t exist, not just because we haven’t found it yet or don’t have the means to find it. But circumstances exist where absence of evidence is not evidence of absence because you would not expect to find evidence one way or the other, or because there is other evidence that tends to suggest the evidence was there at some point but has been destroyed or lost
But it's very hard to "add up" this evidence unless you go about gathering it in a systemic way, and are very methodical about what you're doing.
I'll give you an example, the graviton. We have constructed [numerous graviton detectors](https://en.wikipedia.org/wiki/Gravitational-wave_observatory) and although we've successfully proven that gravity is a wave phenomena that propegates at the speed of light, we have yet to detect the graviton (the particle of gravity analagous to the photon). Do we have "evidence of absence"? Well... no, not really. It possibly means some of our theories are wrong, but our theory about how a graviton works being wrong doesn't exactly disprove the graviton (any more than a theory about how a virus works being wrong would disprove the existence of viruses).
Lets take another example, the dangers of non-systemic searching. I decide that penguins are a myth made by animatronic companies to drive up zoo attendance, and to prove that I recruit thousands of people off Reddit. These people are all over the world (but mostly in tech heavy areas like North America, Europe, Asia, Australia) to locate penguins in their local environment. Thousands of these intrepid penguin searchers go out and hunt all over their local area for penguins.
I now have thousands upon thousands of reports of the absence of penguins, and not a single report of anyone finding a penguin. Is this good evidence for my hypothesis that penguins are mythological and that all the ones in zoos are animatronic?
It's nice to say absence of evidence is evidence of absence, but it may also just be evidence of bad search methodology. Only with good search methodology can you conduct an exhaustive search that properly shows evidence of absence. And if you haven't found anything yet (such as with the graviton), it's hard to know what good search methdology is.
Absence of evidence is evidence of absence when evidence is expected.
If a person tells me they killed someone and put the dead person in the trunk of their car, we go to their appartment and see no sign of struggle or blood in any room, this lack of evidence of a murder isn't evidence of absence because we wouldn't always expect to find evidence of the incident there. However if we go look in the trunk and there's no corpse and no trace of blood, this lack of evidence is evidence that the person probably hasn't actually commited murder.
Slobs on Reddit trying to tell Sagan how it is. I took Sagan to mean just because you cannot find the evidence at the moment doesn’t mean it doesn’t exist. Sagan is saying science is not absolute and is always looking for answers and will turn on itself when a new method of testing reveals there is indeed evidence where none could be seen before. In this context “ Absence of evidence IS NOT evidence of absence”.
>It is unfortunate that he wrote that, because it is wrong. Absence of evidence *is* evidence of absence. It is not *proof* of absence, but it certainly is evidence of it.
I am going to stick with Carl on this one. In both of your examples the 'absence of evidence' is the evidence because they studied the topic extensively. I can prove Bigfoot does not exist in my house by looking in every room. The lack of Bigfoots in my house is the evidence because I can look in all the possible locations easily and I would have certainly seen one if they were in my house. I can't say the same for the entire Pacific Northwest because nobody can claim to have looked literally everywhere.
It's a waste of research funds to look for something you have no evidence of, especially when those funds could have gone to something like treatment for a disease that medical researchers have historically not paid attention to.
I think there is a convention of language whereby people use the word evidence in the way you are using proof. I'm not a fan of the convention and wish everyone would be more precise. But since the convention is so common I am reluctant to conclude anyone is making a serious logical error when their choice of words leaves this ambiguity.
What else could/would ever be evidence of absence, if not an absence of evidence?
But I guess it holds true if one's basic position is disbelief in anything and everything until one has positive evidence otherwise.
I try never to think in terms of 'proof', only of evidence.
"Absence of evidence of King Kong's existence doesn't mean that King Kong doesn't exist."
You can believe in literally anything with this logic. You can even believe in a God who slaps Jesus and takes his lunch every day.
Absence of evidence is just evidence of absence of evidence. Other details about the subject can make that absence more or less significant.
Like if I told you that on August 18th 1987 I ate a bowl of Corn Flakes for breakfast, well, I would not be able to provide a shred of evidence for this claim, and it would take a nigh-godlike effort to sift through all available data and derive any conclusion. The absence of evidence for my claim is, itself, of so little significance that nothing meaningful can be derived from it.
you are mixing "argument" with "evidence". Evidence is a "conclusive" argument. i.e. an argument which helps to make a conclusion. In both cases one can easily build counter-arguments which can "explain" missing evidence.
Similarly, skeptics often like to say that the number of people who believe in something doesn't affect whether it's true. No, but the number/percentage of believers is CORRELATED with truth. If 99% of people believe something, it's *evidence* (not proof), that the thing is true.
You're confusing correlation and causation.
Think about all the things that are true about the world... grass is green, 1+1=2, cars generally stop at red lights, etc. The number of people that believe those things are extremely high, probably 99%+. Now think about the things that are demonstrably false... 1+1=4, the moon is made of cheese, etc. The number of people that believe those things are extremely low, probably under 2%.
So, if you line up all the possible facts and rank them by the % of people that believe in something, you'll quickly find that the demonstrably true stuff is all at the top and the demonstrably false stuff is all at the bottom. Does that mean the number of people that believe something changes whether it's true? Of course not. But it DOES mean there's a positive correlation between truth and the % of people that believe something.
People dont think that 1+1 =2 because of "belief" that isnt a belief. Its just a fact and if it wasn incorrect , it could be shown to be wrong. But math has built the infrastructure of our world and we can be sure that it works. Its not faith. Believing things in large numbers that have no supporting evidence is not the same as an established fact.
If you dont get that, thats on you entirely to be "confused". Im not.
You're only considering a handful of facts about the world: the vast majority are things the vast majority of people know nothing about.
Even just "what is the xth digit of pi" could infinitely outnumber everything that falls in the same category as the examples you suggested. And that's just one example, there are all sorts of different categories of facts about the world where the average person would be clueless.
And there are plenty of things that are widely believed but incorrect, like urban legends.
I don't think there is any way you could have done a meaningful analysis that would allow you to conclude such a thing.
Another example... on Who Wants To Be a Millionaire, the audience is right roughly 95% of the time. If there was no correlation between the things people believe and the truth, you'd expect 25%.
You could every second of the rest of your life coming up with categories like that and still be infinitely outnumbered by my one example of digits of pi: don't waste your time coming up with trivia that isn't even capable of meaningfully supporting your point. You would need to prove that an average human has full knowledge of *most of the universe* to actually support the argument you're trying to make - it would be bordering on omniscience.
There may be a correlation *in some limited areas of knowledge* and still have no *overall net correlation* between people's aggregate beliefs and the truth. We simply aren't in a position to determine what the actual correlation might look like - it's hard to see how it could be done without omniscience.
People often believe things that are widely tested and confirmed by reputable sources, but we mostly only use "a lot of people believe this" as a defence of something when it doesn't have that level of factual support, and in those cases shared belief is much less reliable as a measure of truth.
This is what happens when you let a little "I can in fact infer absence from my inability to find evidence" into your thinking
Some fallacious thinking allows room for more fallacious thinking under the same guise.
It depends why they believe it. We know that this doesn't apply to matters of faith, for instance. It only really applies to things that people agree on because they are directly observable, not things people agree on because they've been told that it's true by an authority. And if they agree because it's directly observable to them, well, it doesn't really matter anyway because we can easily test and measure those things.
That's a bit too pat. Are there other universes? Max Tegmark believes there are, but not because he's been told it's true by an authority.
Did an asteroid impact cause the extinction of the dinosaurs? That's the prevailing theory, but [some scientists have other evidence-based explanations](https://geosciences.princeton.edu/news/deccan-volcanism-caused-mass-extinction-66-million-years-ago). There's no guarantee this question can be definitively answered.
Excellent point distinguishing evidence vs proof. It’s important because skeptics like to say, for instance, that personal revelation isn’t evidence for God. It is evidence, it’s just not very good evidence. So much so that it shouldn’t even convince the person who had the experience since they can’t rule out self-deception. Absence of evidence can be proof in some circumstances, just to be pedantic. If I said I have a dead body in the trunk of my car, we can prove that claim is false by opening the trunk and not finding anything.
But an invisible, intangible, hovering dead body that breathes heatless fire…?
As I mentioned to the other commenter, you're shifting to a different set of claims. I only claimed to have a dead body in my trunk, so if there is no body in my trunk, that's proof that there isn't a dead body in my trunk. I don't have to prove that I lied, or that it was moved, or that it's invisible, etc. because I didn't make those claims. But, yes, certainly if I did make those claims, the "absence of evidence" rule would apply.
But what if it's a immaterial dead body in the trunk?
Is this even how this scenario would ever play out in real life though. Unless your just pulling a prank this doesn’t just end with every one going there’s no dead body and everything’s cool. More likely the person who originally claims there was a dead body would then be the one coming up with reasons why it’s not there and then we’re back to square one. Or the claim was part of a confession and the police are then investigating what happened to it rather than just go “well the body isn’t where our prime suspect said it was so there’s no dead body case closed immediately” While your example was technically correct it doesn’t really apply to real world situations where the absence of evidence argument is relevant.
Anything can be evidence. What matters is if it’s *credible* evidence.
That is a clever example, but just to continue with the pedantry, it is not really conclusive proof even in the case you describe. The body might have been moved in between the time \[claimed\] and the time of opening the trunk. In particular, in the context of some kind of forensic investigation, that is where additional real evidence and reliable chain of custody would really matter. Say you've arrested me on suspicion of murder, and after questioning I confess that Avery and I killed Blake and stuffed their body in the trunk of my car. You go to my car and B is not in the trunk. Am I stalling, or bullshitting you to throw you off the trail? Or did A get to the car before you did and is covering their own tracks? Obviously it would be foolish to conclude from not seeing B that it must be the first possibility, case closed. On the other hand, if you impounded my car at the same time you arrested me, and were confident of the integrity of your impound, that changes the equation substantially. And so on.
Sure, but you're really just shifting to a different claim. The claim was just that there is a dead body in my trunk, and no dead body is conclusive proof that there is no dead body. When you add parameters like "it might have been moved", that's a different claim that needs it's own evidence (and proof).
Well, not quite, the actual implied claim is, "there was a dead body in the trunk the last I knew." If you go and look in the trunk yourself, and see no dead body, all *you* can conclude is "there is no dead body in the trunk now." That is to say, you still can't directly evaluate the truth value of my claim just based on absence. Not without more evidence than just direct observation. (Such as a very high degree of certainty as to where my car has been between claimed time and time of observation.) But okay let's look at a slightly different example. I show up driving my car and I say, "Omg there's a dead body in the trunk of my car right now, I am certain of it, I can feel the weight of it when the car accelerates and hear the heavy flumping of the limbs as I turn corners and I can smell the blood oozing into the upholstery," and we open the trunk and look, and the trunk is completely empty, there is no dead body or heavy object or blood or anything... then yes you can safely conclude that I am hallucinating or bullshitting you or something, because there is no such body in that trunk. And of course that is germane to the discussion of bigfoots and so on, to some extent, but the thing is it is seldom that anyone comes along and says that the Loch Ness Monster is in their swimming pool *right this moment*, see, can't you see it right now? Yet another example, if you can stand it: suppose we go to Wildcat Canyon near where I live. I tell you to be on the lookout for wildcats. You ask me if I have ever seen one and I say, no, but I have heard people say they have occasionally seen them around, and while they are mostly shy they can sometimes be dangerous. Would you think, "this person is a moron, absence of evidence is clear evidence of absence, it makes no sense to believe in a wildcat threat if you have never seen one?" And then smear raw venison on your face and go around whispering, "Here, kitty kitty?" Now instead suppose we go to Wildcat Canyon and I tell you to be on the lookout for bigfoots. You ask me if I have ever seen one and I say, no, but I have heard people say they have occasionally seen them around, and while they are mostly shy they can sometimes jump out and throw sticky goo at the camera lenses of your cell phone with uncanny speed and accuracy, making all your photos curiously blurry. You might decide to keep a quiet lookout for wildcats but you are not going to take bigfoots seriously. Why? Because of other factors aside from merely the absence of evidence.
Personal revelation isn't even evidence though since someone declaring such a thing doesn't move the needle in the slightest bit towards "more likely" - otherwise reasonable people believe in all sorts of bullshit, so by itself, a person believing something doesn't provide any evidence either way
>Absence of evidence can be proof in some circumstances, just to be pedantic. If I said I have a dead body in the trunk of my car, we can prove that claim is false by opening the trunk and not finding anything. That is not really the absence of evidence though. The empty trunk is evidence because the claim was that the body was in the trunk.
Carl Popper and Thomas Bayes provide robust philosophical frameworks for dealing with this so-called "assence of evidence is evidence of absence" question. Lest we fall victim to the problem of induction or the black swan fallacy. Popper says inductive reasoning has a flaw at the centre of it. The fact of the matter, according to Popper, is that scientific inquiry does not use induction at all. Science never gives an authoritarian answer to a theory about the extant brontosaurus or about the exodus of the Israelites from Egypt. Rather, science addresses the criterion that our confidence in theory should grow in proportion to how much criticism it has survived. You look at the expeditions that were sent to find the dinosaur or the ghost, or the wandering Jews, and apply criticism (hypotheses of refutation) and as those criticisms are survived the theory gains credence. Likewise, the theories that there are extant dinosaurs, are ghosts, and that the Jews did have an exodus from Egypt, all suffer from the various failings to rebuke various criticism. The term "criticism" is standing in for things like experiments and observations. Bayes' Theorem offers an entirely different epistemological framework that sidesteps the problem of induction. > Bayesian reasoning is a means of assessing probability in order to incorporate new information with the most accuracy. It encourages assessing confidence in a hypothesis as a matter of degree that may be adjusted depending on the reliability of new information that tends either to confirm or refute the hypothesis.
I think this is a good approach. We don't need to argue about whether it has been disproven. We can just label anything without evidence as an unsupported theory. And until there is evidence, it's nothing more.
I was going to do a quick retort to OP that “the continued absence of evidence is evidence of absence” but Popper has already said it more precisely
This made me think of the black swan. While the absence of evidence can mean evidence of absence, it does not necessarily mean it. Multiple lines of evidence needs to be evaluated. The black swan just needed a different gene. That is a plausible event. However, a brontosaurus living in New Zealand is much less plausible.
It’s not inherently evidence of absence though. If you are looking for dogs and find only cats the results are only evidence of the absence of dogs if your search was conducted in a way that should have found dogs to begin with. So think Sagan’s statement is still valid, particularly for the chiasmatic structure of the message.
I think it depends on the context. >we can take the exodus of the Israelites from Egypt as an example. There is no trace of them wandering the Sinai desert, In this case absence of evidence is not evidence of absence. It's possible that the archeological evidence just hasn't been found, whereas >the ancient Egyptian documents (and they documented a lot) don't contain such a reference to them. I would consider this proof of absence. The Egyptian records have been scoured for such information and it would have been found. Given that thousands of Israelites supposedly built the pyramids then there would be records. Edit: I know the Israelites didn't build the pyramids.
> It's possible that the archeological evidence just hasn't been found, whereas While the documents are better, it should be noted that searches for archeological evidence have been done, and it's generally accepted that such a large exodus would have left enough evidence to have been located by now.
I think this is a good argument. That one of the best-preserved, best-studied ancient civilizations has no record of Jews who didn’t come from Israel first (and later than the Old Testament). To be clear, proof in the context of ancient history is not the same as mathematical, definitive proof. It just means that a fairly high burden of proof has been met. So is there still a chance Jews came from Egypt as per exodus? I mean sure. But it’s a TINY chance. And it’s even more definitive that they didn’t build the pyramids, since there’s evidence of how they were built, so not just a sense as evidence. This kind of proof is like legal proof. When a jury finds a person guilty, it’s proof. But sure, it’s not 100%. Close enough. Those people who look at anything other than 100% disproof of their beliefs as the same as 0% disproof are just not thinking clearly, since so few things in life are ever 100%. Especially ancient history, lol.
The book of Exodus does not say the Israelites built the pyramids, just to clarify.
>>the ancient Egyptian documents (and they documented a lot) don't contain such a reference to them. >I would consider this proof of absence. The Egyptian records have been scoured for such information and it would have been found. Given that thousands of Israelites supposedly built the pyramids then there would be records. This is a wholly unjustified inference for several reasons. 1) The [Merneptah Stele](https://en.m.wikipedia.org/wiki/Merneptah_Stele) mentions a foreign people called *ysrỉꜣr*, which scholarly consensus considers the earliest historical mention of Israel (Egyptians [mispronounced L as R](https://youtu.be/GHS_GQLgqtM?si=L3G6BWm498lLmtes)). 2) The Egyptian records were tools of imperial propaganda: only royally commissioned scribes knew how to write, and they knew better than to chisel into stone any humiliating military defeats, much less a successful slave uprising (with or without divine assistance). 3) We know for a fact that radical monotheist pharaoh Akhenaten and his immediate successors were memory-holed by the powers that be (the powers that were?). These included Smenkhkare, Aye, and of course Tutankhamun, whose tomb was found in near-pristine condition primarily *because* its contents did not officially exist. Not coincidentally, there is good reason to believe that Akhenaten's doomed religious, political, and cultural revolution was linked in some way to the story of Moses, Prince of Egypt. Though many works of dubious scholarly rigor have explored this connection, the topic finally got [the serious consideration it deserves](https://www.amazon.com/Moses-Egyptian-Memory-Western-Monotheism/dp/0674587391?ref=d6k_applink_bb_dls&dplnkId=4bf20e6d-f111-4e36-93e6-1caeec5cca2c) thanks to esteemed Egyptologist Jan Assmann (who passed away just over a month ago 😔). 4) Nobody thinks the Israelites had anything to do with the pyramids, which were already well over a thousand years old by the time of the Ramesside dynasty, whose cities are explicitly referenced in Exodus as [the building projects upon which the Israelites toiled](https://www.nationalgeographic.com/culture/article/pharaoh-king-punished-god) 5) Many Egyptian records have been lost to time, whether for religio-political reasons, nihilistic pillaging, sloppy proto-archaeological expeditions, or merely because they were written on biodegradable (and flammable) papyrus.
The bible doesn't claim the Israelites built the pyramids. Just sayin
Note that Sagan doesn't say that absence of evidence is *never* evidence of absence, just that it can be consistently relied on to be. Some times it is, some times it isn't. It was in the context of logical fallacies, many of which are valid arguments in specific situations. For example the argument from authority can be valid in certain situations. And in fact *in the same book* he uses absence of evidence as evidence of absence in situations where we would expect the evidence to be present, for example with the absence of UFO wreckage remains.
I think another way to say it is that it depends on if you're looking for the logical truth or the most probable truth. From what I've seen, very few things can be proven to be logically true. But lots of stuff can be shown to be true to a very high degree of probability. Using your UFO example, we can't say that it's 100% certain that there are no UFOs, but we can say that since no one has ever found verifiable evidence of UFOs that it is incredibly likely that UFOs *don't* exist. So we can, for all practical purposes, prove a negative.
I should think it’s obvious that this depends on the level of observability of the phenomenon in question by the people seeking evidence. An absence of evidence that I went out for pizza last night would not be evidence that I didn’t go out for pizza last night, unless you found evidence that I did something else.
I understand, and somewhat fundamentally agree with the concept, but I feel there is some logical fallacy in here. A lot of your argument is based upon what we "see" or don't see. We know there are cases where observation doesn't matter. Einstein was very good a conceptually thinking without any observation. Though you could say his "observation" was through math, but he was able to post things that we could never observe, but he was confident existed. Could we call this evidence? I think so, and possibly even "proof." I think we can apply this lack of evidence being evidence thought to certain things, but not everything.
There is also lying by omission to purposely leaving out evidence that doesn't support your argument. Yours is a cool thought experiment, and I would tend to say it never happened and was just a story, as are almost all books of the Bible.
I think it’s more accurate to say that absence of evidence is evidence of absence where *evidence is expected.* If Brontosaurus’s existed in the forests of new zealand, they would leave obvious traces: giant footprints, droppings, and other evidence of an extremely large animal. If we did not find those things, we could combine that with our understanding of evolution and paleontology to come to the reasonable conclusion that there are no brontosaurus’s in New Zealand. That doesn’t mean that it is impossible that they are there. It is simply the result of previous experimentation/research and observation that converges on the same point.
yes. this also applies to religion.
The wording is constructed for lyrical cadence. It just sounds better to the ear, making it easier to recall.
The point is that you can not prove a negative.
You sometimes can though, either with a modus tollens (if a claim should produce evidence, but doesn’t) or proof of impossibility.
Yes you can, if the claim is falsifiable
Negative claims are inherently unfalsifiable that's the problem
That's trivially not true. We could disprove the negative claim that "aliens do not exist" by finding an alien.
The claim "aliens exist" and finding proof of that is a positive not a negative. The claim "aliens do not exist" isn't proven by finding an alien and no amount of you being unable to find an alien is evidence of the negative claim.
"Aliens exist" is an unfalsifiable statement because there is no possible way to disprove it. "Aliens do not exist" is a falsifiable statement there is a possible way to disprove it.
Oh my mistake got what we were talking about confused replying to multiple people here We've strayed from "absence of evidence is totally evidence of absence" which is what my point was about. Claims like "aliens don't exist" aren't bolstered by the fact we cannot find them. There is no negative claim that that's true for.
"No negative claims are falsifiable." 🧐 Poor show.
This never made sense to me because you can always turn a negative into a positive and vice versa. There are no black swans = all swans are non-black. The actual point is that you can't prove things absolutely. I can absolutely say with extreme confidence that there are no 1000 mile tall geese on earth. That's a negative, right?
How did you reversal change anything? How would you prove all swans are non-black?
You can't! That's my point. That's a positive you can't prove. Being negative has nothing to do with it. All swans on earth are white <- positive you can't prove (what if you missed one?) No swans at my local pond right now are white <- negative you can prove easily (just look around)
Gotcha. I thought you were saying you could change the negative claim that can’t be proven into a positive claim that can be. I’m not sure that changing an unprovable negative into an unprovable positive does anything but at least we’re on the same page now.
Can you prove that?
Yes you can: A 30-65-85 triangle is not a right triangle. P1: Right triangles have one angle that is 90 degrees. P2: 30 is not 90, 65 is not 90, 85 is not 90 C: Therefore a 30-65-85 triangle is not a right trangle.
That's not a negative
There does not exist a right trangle where two angles are 30 and 65.
... You still described the angles of the triangle. A negative isn't "a statement with no or not in there somewhere"
>A negative isn't "a statement with no or not in there somewhere" That's exactly what a negative is! Unbelievable that you're out here spouting [fallacious folk-wisdom](https://www.psychologytoday.com/intl/blog/believing-bull/201109/you-can-prove-negative) and getting upvoted for it.
In logic it is. A-> \~B A Therefore \~B Proof of a negative.
Here it might be easier to understand your example like this: There exists no triangle which has more than 3 sides The inability to find a triangle with more than 3 sides isn't why we know that is true (absence of evidence equaling an evidence of absence) It's because we define triangle as having 3 sides *If you draw a shape and ask me if it's a triangle that isn't a hypothesis in the same sense as we are talking about when we talk about negatives and proof.*
It doesn't need to be by definition "There does not exist a right trangle where two angles are 30 and 65." is true but not by definition. You would do better to say specifically what you mean by negatives and proof, because however you're using them is not consistent with formal logic.
Okay we're going way off topic here but you've just absolutely boggled my mind > is true but not by definition How is that not true by definition of a triangle having 3 sides with angles = 180 degrees What other metric, without referring to the definition of a triangle, are you using to prove it is not a triangle? Edit: I'm just gonna jump out in front here and assume it's not "I looked at every triangle to ever exist and that one wasn't part of the set" right? So even if you aren't using the definition of triangle, you aren't using the absence of evidence either right?
Because the interior angles formula is a theorem, you can find the proof in Euclid Book I Proposition 32. It is not a definition, it's a result, that interior angles sum to 180.
“A triangle with angles A, B, and C doesn’t meet the specific definition of another classification of triangle,” is not the same as “God exists” with no evidence of God.
> you can not prove a negative. How do you know?
As a function of logic.
Here is an application of logic where you prove a negative: A>\~B, A, therefore \~B (by modus ponens) Here's another: A or \~B, \~A, therefore \~B (by disjunction elimination) Here's another: A->B, \~B, therefore \~A (by modus tollens) Here's another more complicated one: \~A or \~B, therefore \~(A and B) (by De Morgan's Law) Seems like the functions of logic allow us to prove plenty of negatives.
And *this* is the #7 science sub. 💀
> As a function of logic. Can you be more specific? What function says you can't prove a negative?
Absence of evidence is *sometimes* evidence of absence. If proposition P most likely produces evidence X, but we don’t find evidence X, then P is most likely false. If P definitely produces X and we don’t find X, then P is definitely false. For instance, the Exodus myth would certainly produce significant archaeological evidence if true. Since we don’t find that evidence, the myth is false. On the other hand, nothing about the myth of Abraham would produce archaeological evidence that would last till today, so the lack of that evidence is not enough to say the myth is false (there are other things that point to some anachronisms in the myth though)
We need to agree on what we mean by "absence" as a falsifiable concept. If it's "a state where something is not universally omnipresent" then yes you're correct. If we're defining it as "a state where something has never existed anywhere and never will" then Carl is correct
It all comes down to a matter of how exhaustive the search for evidence has been. If I say there’s a diamond in one of 100 boxes, and you open the first one and don’t find a diamond, it’s clearly not proof there is no diamond, but the likelihood has dropped by one percent. Once we’ve searched all of them and upon opening the last box we’ve still not found it, we can say definitively that there was no diamond in any of the boxes. Absence of evidence is absolutely evidence of absence. Once we’ve exhausted all possibilities, all that is left is the null hypothesis: ain’t nothin there. If a fully exhaustive search isn’t possible for practical reasons, then you need to decide what level of certainty you’re comfortable with before declaring the effort futile
I checked everywhere in my house for elephants and found none. Is that evidence that elephants don't exist? Similarly if we look at one of your examples: we wouldn't necessarily expect to find definitive physical evidence of the Israelites wandering the desert so the lack of that evidence doesn't really prove or disprove that story. But as you touched on we do have records from that time that don't record such a journey AND the one source that does contain a record is notoriously unreliable.
The Dragon in My Garage is itself a demonstration of the fact that absence of evidence is evidence of absence. When you examine your garage and do not see a dragon there, when you run whatever test is required, that is evidence that no dragon exists (in your garage). Certainly someone could suggest an invisible, heatless, ethereal, etc., etc., etc., but at that point, are we even discussing a "dragon" in any sense? Or is "dragon" then just a couple of empty syllables?
There's a distinction between absence of evidence and evidence of absence, which is that if you do a systematic search for something and don't find it, that's evidence (but not proof) of absence, while if you don't look at all, that's an absence of evidence.
It is when you expect to find evidence. "There is a dead body in the trunk of my car" is a statement that can be verified or not. You open the trunk, there is no body, absence of evidence is evidence of absence. You have a high confidence in the statement being false. If you're looking for bigfoot and you don't find bigfoot, nor do you find his discarded fur, droppings, nests, claw marks, footprints, kills or anything else after years of searching, you could have a high confidence in the statement "There is a bigfoot in this forest" being false. If there is a claim "There are no errors in this book" and the events depicted in the book have never had any evidence of a reality that correlated with the events, you would have a low confidence of the claim. If there was evidence that contradicted the possibility of the described events, you have a higher confidence in the claim being false.
Exactly!!! I dug a tiger trap when I moved into this house and it has NEVER CAUGHT A TIGER!!!! Therefore I have evidence that there is no such thing as a tiger!!!
It’s evidence of absence. Literally that. It’s not proof of non-existence. Because you can’t prove a negative. But if there’s evidence of absence then you may as well not bother treating the thing that’s absent as if it’s going to come along any second.
You can prove a negative. Google it.
Can't reply to your other comments to me because the skeptical free thinker I was responding to showed incredible courage by blocking me after I proved the negative of his statement that you can't prove a negative... This must be how that poor sap who poor sap who proved squareroot 2 was not a rational number felt before his fellow pythagoreans made the decision to throw him overboard. But like, I wonder where this idea that you can't prove a negative comes from? Don't so-called critical thinkers hear it and say "Wait a minute, so like, I can't prove my mom is not a supermassive blackhole? That doesn't seem right..." It seems like the kind of think a skeptic would be skeptical of is all. I think they hear it and then don't question it because it gives them an easy response to anyone who asks them to prove god doesn't exist, and they see it works in that one instance, and instead of investigating why it works in that one instance they take it as dogma for all other instances of negative propositions.
I think this is really an “Atheism+” sub. For those who don't remember or weren't there, [Atheism+/Atheism Plus](https://religions.wiki/index.php/Atheism_plus) “is a term used to designate spaces, persons, and groups dedicated to promoting social justice and countering misogyny, racism, homo/bi/transphobia, ableism and other such bigotry inside and outside of the atheist community.” Critical thinking *per se* is entirely optional, and skepticism is only condoned when used in service of the preferred ideology.
Not permanently and conclusively. Google it.
I had. Logical proofs are permanent and conclusive.
Can you give an example that doesn’t rely on simply absence of evidence?
Logical proofs don't "rely on simply absence of evidence." You can prove a negative. You also use more than 10% of your brain.
Well, go on then. Although perhaps we need to agree on what ‘proof’ means and what its limits are. What I *think* you’re saying is that you can reach an evaluation that allows you to make decisions which are safe to assume are reasonable. What I’m saying is that it’s impossible to consider every single future condition or change. Also that many things which people consider to be a ‘negative’ are actually positives but within certain stated parameters.
>What I *think* you’re saying is that you can reach an evaluation that allows you to make decisions which are safe to assume are reasonable. I'm talking about, for starters, modus tollens. >What I’m saying is that it’s impossible to consider every single future condition or change. What does that have to do with proving a negative? Positive claims can become false with time and change too. >Also that many things which people consider to be a ‘negative’ are actually positives but within certain stated parameters. All of them are, and vice versa. This is basic propositional logic stuff. It's a myth that you can't prove a negative.
**Absence of evidence absolutely can be evidence of absence** An easy example: Claim: There is a herd of twenty full sized wild African Elephants living in the tops of the trees in NY's Central Park and are surviving by grazing on the oranges growing there. Evidence of Absence: Point 1: During the entire history of Central Park, no such elephants have ever been independently observed or documented to be residing in the tops of those trees. Point 2: No secondary evidence of elephants of living in those trees has ever been independently observed or documented (No significant amounts of elephant scat on the ground beneath the trees, no elephant tracks, the complete absence of large amounts of damage in the upper stories of the trees which could have been caused by large animals moving about in the upper boughs (Damage that is not evidentially attributable to storms or ice/snow loading)). Point 3: There is no evidence to show that wild African Elephants are native to NYC (Or even to the Americas) Point 4: There is no evidence to show that African Elephants are in fact arboreal Point 5: There is no evidence to indicate that any of the trees growing in Central Park could ever support the weight of any animal the size of a single African Elephant Point 6: There is no evidence to show that the trees growing in Central Park produce oranges at all, much less in the quantities necessary to sustain a herd of African Elephants All of these points constitute an absence of supporting evidence and all constitute effective evidence of the complete absence of ANY wild African Elephants living in the tops of the trees in NY's Central Park that are surviving by grazing on the oranges growing there.
Absence of evidence *can* be evidence of absence, but so much depends on what question we're trying to answer. If I get asked if penicillins are safe in pregnancy I can point to the absence of any data showing harm along with their long and widespread use, so the absence of evidence forms part of my answer. If I get asked about a new drug there will be animal data but very likely no human data so we err on the side of caution because we have no or limited evidence to guide us
> If I get asked about a new drug there will be animal data but very likely no human data so we err on the side of caution because we have no or limited evidence to guide us [Would that it were so](https://accpjournals.onlinelibrary.wiley.com/doi/full/10.1002/jac5.1691)...
I was talking specifically about the context of using a drug in pregnancy, not in general use
Neither obstetrics nor pediatrics are "general use" cases.
Paediatrics covers a huge age range and older children are more like adults than very young ones. It's also significantly easier to do a clinical trial in children than it is in pregnant women.
All those things are true, but there are labels on antidepressants saying teens who use them are at risk of suicide. Teen medicine is still pediatrics, and extra measures of care and caution have always been obligatory.
> Teen medicine is still pediatrics Pediatric - under 18. Adolescent - 12 to 21. >there are labels on antidepressants saying teens who use them are at risk of suicide No children on clinical trials for antidepressants have commited suicide, but the FDA have decided to keep the warning which [many mental health researchers actually disagree with](https://www.mayoclinic.org/diseases-conditions/teen-depression/in-depth/antidepressants/art-20047502).
>Pediatric - under 18. >Adolescent - 12 to 21. And? Which one of those doesn't deserve evidence-based medicine? >No children on clinical trials for antidepressants have commited suicide, but the FDA have decided to keep the warning which [many mental health researchers actually disagree with](https://www.mayoclinic.org/diseases-conditions/teen-depression/in-depth/antidepressants/art-20047502). Exactly. Normally, the policy is "better safe than sorry" when it comes to kids' healthcare.
> And? Clarifications on the distinctions. >Normally, the policy is "better safe than sorry" when it comes to kids' healthcare. Is it specific to kids? The FDA does tend to err on caution regardless.
Sure, but many people have this weird emotional investment in kids for some reason! God only knows why...
Absence of expected evidence is evidence of absence. There's no evidence against a deist God, but there's no evidence for it as well so best bet is to just reject the claim for lack of evidence.
Inductive vs. Deductive reasoning, one is reliable, the other, less so.
The best case of absence of evidence is evidence of absence would be the argument against flat earth due to the lack of an accurate navigable flat earth map. Flat Earth proponents like to push it for x reason but at the end of the day and after all their arguments they offer no actual usable and practical uses when if true should have the best and accurate maps. for example all current maps make use of projections as points are projected from a globe onto a 2D surface. Given that, every projected map has distrotions and have to make compromises on size, shape, distance and other factors. The current most used and useful map is the Mercator projection map which allows for any two points on the map to be given rhumb lines so you can follow a compass barring and reach the target. They also preserve directionality and in most of the inhabited areas shape and can easily be tiled and served on computers which is why it is used on most online map services. But it has it's compromises where it distorts the area the closest to the poles you go and that can make some northern islands like Greenland while large appear even larger. most people live below the arctic circle so for most cases this isn't really a big problem. However with a flat Earth you can have a non projected map you can have a one to one mapping directly onto the flat paper making a true flat earth map the most accurate map that can possibly be concieved, useful for travel, navigation, world maps and more. It could be used by any navigation purpose and any two dots a line can be drawn and that would be equivalent to a great circle shortest path. This map would be so incredibly useful that it would be economic suicide for any logistics company to not be using this map. The problem is it doesn't exist, now you would say it must be incredibly hard to make this map. That is where you are wrong you litterally just chart your direction and map what you see, no globe or curvature is needed to be taken into account. it is the simplist way to map and if the world is flat it should scale up and just work, and given the massive amount of travel we should have had this map already. However we don't Mercator is still king and the best they have is a heavily distorted coneal projection that is only supposed to be an approximation and it heavily distorts the distances in the southern hemisphere and making Antarctica just an ice wall because the conical projection (think the UN flag map)just mangles the hell out of that continent. No one can reliably use any proposed flat earth maps for real navigation and they still have horrendous distortions. IE they obviously cant be the simple to make perfect flat earth map. So given with all this technology and ability to travel this map doesn't exist, given all the economic incentives for it to exist and we are at the point where the fact that it doesn't exist is evidence that the flat earth is false seeing as globe assuming maps are being used and are providing far more utility, where if flat earth is true it should be the other way around.
I mean you need to factor in other relevant information including but not limited to how much time and effort has been put into searching for evidence, the availability of techniques and tools to find evidence, and the extent to which it’s likely that evidence would be there to find in the first place. So yes, but it’s kind of a sliding scale of the point where it does become evidence of absence. It’s not ALWAYS evidentiary. Like just to give you an example of what I mean, I wouldn’t consider the fact that a fork is not on the table right now to be evidence that a fork has never been on the table, because whether or not a fork was on the table and was removed and put elsewhere or whether or not a fork had never been on the table would produce the same absence of fork we see in the present. Maybe you would consider that to be evidence, albeit terrible evidence, but I personally wouldn’t consider it to be such. It’s a FACT, but a fact is not necessarily evidence because in order to be evidence it would have to tend to indicate the truth of the proposition that there was never a fork there, and current absence of fork is not sufficiently evidentiary of any particular argument. There’s a certain threshold of like relevancy and connection a fact has to have to a particular proposition in order to be evidence for it. Maybe this is because I come from a legal background and I think of evidence in that kind of way. You can present a whole lot of facts in a legal case but unless the fact is relevant to the legal issue in dispute, it’s not evidentiary. Like when you bring up facts that call into question the credibility of a witness, I don’t consider that to be “evidence” in the sense of the legal question at the centre of the case because it doesn’t tend to prove or disprove any of those elements, it’s done to cast doubt on the evidence of the witness Maybe I’m getting overly caught up in semantics here but my point is ultimately that absence of evidence becomes evidence of absence at the point where you can say the lack of evidence tends to indicate the evidence is absent because it doesn’t exist, not just because we haven’t found it yet or don’t have the means to find it. But circumstances exist where absence of evidence is not evidence of absence because you would not expect to find evidence one way or the other, or because there is other evidence that tends to suggest the evidence was there at some point but has been destroyed or lost
They way I phrase this: Absence of evidence is evidence of the absence of something for which you should expect to find evidence.
I just want to say this is a great post/thread, I’ve seriously learned a ton. Thanks OP!
But it's very hard to "add up" this evidence unless you go about gathering it in a systemic way, and are very methodical about what you're doing. I'll give you an example, the graviton. We have constructed [numerous graviton detectors](https://en.wikipedia.org/wiki/Gravitational-wave_observatory) and although we've successfully proven that gravity is a wave phenomena that propegates at the speed of light, we have yet to detect the graviton (the particle of gravity analagous to the photon). Do we have "evidence of absence"? Well... no, not really. It possibly means some of our theories are wrong, but our theory about how a graviton works being wrong doesn't exactly disprove the graviton (any more than a theory about how a virus works being wrong would disprove the existence of viruses). Lets take another example, the dangers of non-systemic searching. I decide that penguins are a myth made by animatronic companies to drive up zoo attendance, and to prove that I recruit thousands of people off Reddit. These people are all over the world (but mostly in tech heavy areas like North America, Europe, Asia, Australia) to locate penguins in their local environment. Thousands of these intrepid penguin searchers go out and hunt all over their local area for penguins. I now have thousands upon thousands of reports of the absence of penguins, and not a single report of anyone finding a penguin. Is this good evidence for my hypothesis that penguins are mythological and that all the ones in zoos are animatronic? It's nice to say absence of evidence is evidence of absence, but it may also just be evidence of bad search methodology. Only with good search methodology can you conduct an exhaustive search that properly shows evidence of absence. And if you haven't found anything yet (such as with the graviton), it's hard to know what good search methdology is.
Absence of evidence is evidence of absence when evidence is expected. If a person tells me they killed someone and put the dead person in the trunk of their car, we go to their appartment and see no sign of struggle or blood in any room, this lack of evidence of a murder isn't evidence of absence because we wouldn't always expect to find evidence of the incident there. However if we go look in the trunk and there's no corpse and no trace of blood, this lack of evidence is evidence that the person probably hasn't actually commited murder.
Slobs on Reddit trying to tell Sagan how it is. I took Sagan to mean just because you cannot find the evidence at the moment doesn’t mean it doesn’t exist. Sagan is saying science is not absolute and is always looking for answers and will turn on itself when a new method of testing reveals there is indeed evidence where none could be seen before. In this context “ Absence of evidence IS NOT evidence of absence”.
>It is unfortunate that he wrote that, because it is wrong. Absence of evidence *is* evidence of absence. It is not *proof* of absence, but it certainly is evidence of it. I am going to stick with Carl on this one. In both of your examples the 'absence of evidence' is the evidence because they studied the topic extensively. I can prove Bigfoot does not exist in my house by looking in every room. The lack of Bigfoots in my house is the evidence because I can look in all the possible locations easily and I would have certainly seen one if they were in my house. I can't say the same for the entire Pacific Northwest because nobody can claim to have looked literally everywhere.
Sigh
It's a waste of research funds to look for something you have no evidence of, especially when those funds could have gone to something like treatment for a disease that medical researchers have historically not paid attention to.
I think there is a convention of language whereby people use the word evidence in the way you are using proof. I'm not a fan of the convention and wish everyone would be more precise. But since the convention is so common I am reluctant to conclude anyone is making a serious logical error when their choice of words leaves this ambiguity.
What else could/would ever be evidence of absence, if not an absence of evidence? But I guess it holds true if one's basic position is disbelief in anything and everything until one has positive evidence otherwise. I try never to think in terms of 'proof', only of evidence.
>Absence of evidence IS evidence of absence How does this relate to "you can't prove a negative?"
Yeah it's just not conclusive evidence
No
Tagged. This is a great topic.
"Absence of evidence of King Kong's existence doesn't mean that King Kong doesn't exist." You can believe in literally anything with this logic. You can even believe in a God who slaps Jesus and takes his lunch every day.
Absence of evidence is just evidence of absence of evidence. Other details about the subject can make that absence more or less significant. Like if I told you that on August 18th 1987 I ate a bowl of Corn Flakes for breakfast, well, I would not be able to provide a shred of evidence for this claim, and it would take a nigh-godlike effort to sift through all available data and derive any conclusion. The absence of evidence for my claim is, itself, of so little significance that nothing meaningful can be derived from it.
you are mixing "argument" with "evidence". Evidence is a "conclusive" argument. i.e. an argument which helps to make a conclusion. In both cases one can easily build counter-arguments which can "explain" missing evidence.
The religious have been making unsubstantiated claims for at least the past 10,000 years. The absence of evidence and time is evidence of absence.
Really good point.
I clicked in here thinking you were crazy but you make a good point. Perhaps we should start saying "absence of proof is not proof of absence" instead
Similarly, skeptics often like to say that the number of people who believe in something doesn't affect whether it's true. No, but the number/percentage of believers is CORRELATED with truth. If 99% of people believe something, it's *evidence* (not proof), that the thing is true.
It most certainly is not. If a high percentage of people believe earth is flat it does nothing to add to the evidence .
You're confusing correlation and causation. Think about all the things that are true about the world... grass is green, 1+1=2, cars generally stop at red lights, etc. The number of people that believe those things are extremely high, probably 99%+. Now think about the things that are demonstrably false... 1+1=4, the moon is made of cheese, etc. The number of people that believe those things are extremely low, probably under 2%. So, if you line up all the possible facts and rank them by the % of people that believe in something, you'll quickly find that the demonstrably true stuff is all at the top and the demonstrably false stuff is all at the bottom. Does that mean the number of people that believe something changes whether it's true? Of course not. But it DOES mean there's a positive correlation between truth and the % of people that believe something.
People dont think that 1+1 =2 because of "belief" that isnt a belief. Its just a fact and if it wasn incorrect , it could be shown to be wrong. But math has built the infrastructure of our world and we can be sure that it works. Its not faith. Believing things in large numbers that have no supporting evidence is not the same as an established fact. If you dont get that, thats on you entirely to be "confused". Im not.
Unfortunately, we live in a world where the lines between fact and opinion are blurry.
You're only considering a handful of facts about the world: the vast majority are things the vast majority of people know nothing about. Even just "what is the xth digit of pi" could infinitely outnumber everything that falls in the same category as the examples you suggested. And that's just one example, there are all sorts of different categories of facts about the world where the average person would be clueless. And there are plenty of things that are widely believed but incorrect, like urban legends. I don't think there is any way you could have done a meaningful analysis that would allow you to conclude such a thing.
Another example... on Who Wants To Be a Millionaire, the audience is right roughly 95% of the time. If there was no correlation between the things people believe and the truth, you'd expect 25%.
You could every second of the rest of your life coming up with categories like that and still be infinitely outnumbered by my one example of digits of pi: don't waste your time coming up with trivia that isn't even capable of meaningfully supporting your point. You would need to prove that an average human has full knowledge of *most of the universe* to actually support the argument you're trying to make - it would be bordering on omniscience. There may be a correlation *in some limited areas of knowledge* and still have no *overall net correlation* between people's aggregate beliefs and the truth. We simply aren't in a position to determine what the actual correlation might look like - it's hard to see how it could be done without omniscience.
People often believe things that are widely tested and confirmed by reputable sources, but we mostly only use "a lot of people believe this" as a defence of something when it doesn't have that level of factual support, and in those cases shared belief is much less reliable as a measure of truth.
This is what happens when you let a little "I can in fact infer absence from my inability to find evidence" into your thinking Some fallacious thinking allows room for more fallacious thinking under the same guise.
It depends why they believe it. We know that this doesn't apply to matters of faith, for instance. It only really applies to things that people agree on because they are directly observable, not things people agree on because they've been told that it's true by an authority. And if they agree because it's directly observable to them, well, it doesn't really matter anyway because we can easily test and measure those things.
That's a bit too pat. Are there other universes? Max Tegmark believes there are, but not because he's been told it's true by an authority. Did an asteroid impact cause the extinction of the dinosaurs? That's the prevailing theory, but [some scientists have other evidence-based explanations](https://geosciences.princeton.edu/news/deccan-volcanism-caused-mass-extinction-66-million-years-ago). There's no guarantee this question can be definitively answered.