What is Evidence?
AchillesSinatra: It gets a bit frustrating to hear, day-in, day-out, year-in-year-out, that there is no evidence for God (from the scientistic nutters) and that there is no evidence for evolution (from the Creationist wackos).
To make any progress on these matters at all, what we need is a set of criteria we can all agree on to determine what does, and what does not, constitute evidence for such-and-such a claim. Otherwise we're just wasting each other's time, relying on personal intuition which is likely to be biased, as opposed to an objective standard of rationality.
Now, there are people who study this kind of thing: philosophers of science.
Interlude: Why, just the other day I went to see the doctor. Doc said "There's good news and bad. The bad is you're very sick and will be dead in a few weeks. The good is we're going to name a disease after you."
Similarly, with scientific evidence, there's good news and bad. The good is: several theories of evidence/confirmation have been suggested. The bad is, as you might have guessed, nothing remotely resembling a consensus obtains, and each theory of evidence is fraught with difficulty.
But anyway, just to get the ball rolling, here are some ideas that have been proposed:
1. The hypothetico-deductive (H-D) method.
Any observation that is entailed by a theory constitutes evidence for that theory.
(For those unfamiliar with the terminology, in logic if P entails Q, it means that if P is true, Q must be true.)
An example of this would be Einstein's general theory of relativity (GR) which entails that light is bent by massive objects. So, on the H-D account, if light is indeed observed to be bent by massive objects, then this constitutes evidence for GR.
2. Inference to the best explanation (IBE).
On this view, if a theory explains an observation (it needn't entail it) better than any rival, then that observation counts as evidence for the theory.
The theory of evolution, ToE, (burp) provides a prime example. This theory (assuming there is such a thing), unlike relativity, seems to logically entail very few, if any, observations. On the other hand, we often hear defenders of the theory claim that such-and-such constitutes evidence because such-and-such is EXPLAINED better by ToE than by any other theory; special creation, say.
Of course, from a set of candidate explanations, how we determine which is the "best" needs a little fleshing out.
Perhaps the most prevalent theory of evidence/confirmation right now. Bayesians tell us we are allowed to assign any subjective probability we like, except zero or one, to a given theory or hypothesis.
Now, just the very mention of the word "subjectivity" in science is enough to give certain methodologists a fit. Never fear, say the Bayesians, as evidence comes in, this probability is adjusted according to the strictly objective canons of Bayes' theorem, and in the long run--supposedly--we all converge on roughly the same figure.
Confirming evidence, from the Bayesian perspective, is anything that raises the prior probability of the theory in question. So, if seeing light bent by the Sun, say, or the discovery of a fossil tiktaalik, raises the probability of your theory being true, then it counts as evidence for that theory.
AchillesSinatra: Indeed, Beaver. Statements such as "Truth is just what is true" and "Evidence is what is evident" are, of course, entirely unhelpful.
Well, is there any evidence for God's existence or not?
Suppose we all agree to adopt "Inference to the Best Explanation" (IBE) as our criterion for evidence. So far so good.
Next we would focus on particular cases, say for example, the complexity of organs such as the eye, or the existence of the universe, or this, that, and the other.
Taking the eye as our example, if the defender of the God theory can demonstrate that, of all the candidate explanations available, the complexity of the eye is explained better by the God theory than any other theory, then voila! - there is at least one piece of evidence for the theory of Divine Creation, i.e., God.
The evolutionists, needless to say, will balk. They will insist that the eye is explained better by their own theory, whatever that is (presumably involving natural selection). Thus, the eye, on their account, constitutes evidence for some Darwinian based theory and no evidence at all for Special Creation.
Obviously, then, we require further criteria to determine which, from a set of candidate explanations, is "the best".
Attempts have been made in this direction too. Peter Lipton, for instance, has written an entire book on the topic entitled -- surprise surprise -- "Inference to the Best Explanation".
Here we need to be wary of circularity. An immediate, albeit careless, response might be: "The best explanation is the one most likely to be true! ".
This gets us nowhere. Remember, what we're trying to do is infer from "E is the best explanation" to "E is true", or at least "E is likely to be true".
Now if the best explanation just is "that most likely to be true" then we end up with the unhelpful tautology:
"The best explanation (i.e., the one most likely to be true) is most likely to be true"
Lipton tries to make a case for what he calls the "loveliness" of an explanation as betokening truth, or truth-likeness.
For more details, cough up the dough and buy his book.
Of course, the whole notion of IBE is disputed. Why should we think that a satisfying explanation is any indicator of truth?
There are also worries that we might be choosing "the best of a bad lot". What if all the candidate explanations are crap? Choosing the best of the bad lot is hardly likely to lead us truth.
Angry Beaver: I'm a simple man, if they want to prove that god is real to me...... ask him to visit me and say hello. But even then, what evidence is there that he is actually god lol
AchillesSinatra: @ Beaver
Remember, what we're discussing here is evidence and not proof. Evidence, supposedly, gives us some reason--though not a compelling reason (i.e., proof)--to believe that a particular claim is true.
I suppose the point I'm trying to make, or one of them, is that the frequent claims made by high profile scientists such as Richard Dawkins that "There is no evidence that God exists" should be taken with a pinch of salt.
Dawkins is effectively saying "God doesn't exist", but to say that in so many words might come across as arrogant and pompous, so he instead cloaks it in a veneer of (putative) scientific respectability.
Next time he does it, just ask, "Professor Dawkins, can you tell us the criteria in virtue of which scientists determine whether such-and-such constitutes evidence for such-and-such a theory?"
That might shut him up. And if it doesn't, he will quickly be shown to be hopelessly confused. (I've done this before with scientists on other sites).
The facts are these:
1. There is no universally agreed upon set of criteria in virtue of which scientists determine whether such-and-such constitutes evidence for such-and-such a theory.
2. When a scientist says that something is evidence, this determination is made according to personal intuition (i.e., "It seems like evidence to me" ), not by appeal to universally agreed upon criteria.
3. This is easily seen by the fact that scientists themselves not infrequently disagree over whether such-and-such constitutes evidence or not.
And, of course, exactly the same applies to our Creationist friends when they claim "There is no evidence for evolution".
AchillesSinatra: "3. This is easily seen by the fact that scientists themselves not infrequently disagree over whether such-and-such constitutes evidence or not." - me (post above)
To illustrate the point, I'm going to reproduce below (as evidence!) something I originally posted in my "Should We Believe What Scientists Say?" thread (page 6).
It's not just that scientists frequently disagree with one another over what counts as evidence. The situation is even more dire, ladies and gentlemen. In the video below, the confusion is such that the very same high profile scientist cannot even maintain a consistent position WITH HERSELF over evidentiary matters.
For reasons that needn't concern you, dear reader, I've been watching a documentary on the Yeti.
At the 1:05 mark, our resident science expert, Eugenie Scott, Executive Director National Center for Science Education, tells us:
"I think the biggest reason why most scientists are skeptical of there actually being a Yeti is that there really isn't any evidence for it."
Then at 38:55, the same expert explains...
"The problem is, I and most of the other scientists I know, would really rather know than believe. And when you look at all the evidence...um, it's pretty unconvincing."
Now, I'm not here to defend the Yeti. He can stand up for himself.
The problem is, Ms Scott, first you told us there is no evidence, then you told us the evidence is unconvincing. How can the evidence be unconvincing if there is no evidence?
On pain of contradiction or equivocation, evidence cannot be at once non-existent and unconvincing. Moreover, one can only wonder how Ms Scott is able to "look at all the evidence" when, on her own account, there IS no evidence to look at.
Far be it from me to criticize a science expert, but it's hard not to get the impression she hasn't the faintest idea what she is talking about.
A familiar story, boys and girls.
1. that which is evident.
2. n. that which tends to prove or disprove something; ground for belief; proof.
3. something that makes plain or clear; an indication or sign: His flushed look was visible evidence of his fever.
4. Law. data presented to a court or jury in proof of the facts in issue and which may include the testimony of witnesses, records, documents, or objects.
5. v. (used with object): to make evident or clear; show clearly; manifest: He evidenced his approval by promising his full support.
6. to support by evidence: He evidenced his accusation with incriminating letters.
1. adj. easy to see or understand; readily apparent
ety. from Latin ēvidēns, from vidēre: To see
Types of Evidence:
1. Analogical Evidence
While not a kind of evidence you’d use in court, this kind of evidence can be useful for increasing credibility by drawing parallels when there isn’t enough information to prove something in a workplace investigation. Analogical evidence uses a comparison of things that are similar to draw an analogy.
2. Anecdotal Evidence
Anecdotal evidence isn’t used in court, but can sometimes help in a workplace investigation to get a better picture of an issue. The biggest problem with this kind of evidence is that it is often “cherry picked” to present only anecdotes that support a particular conclusion. Consider it with skepticism, and in combination with other, more reliable, kinds of evidence.
3. Character Evidence
This is a testimony or document that is used to help prove that someone acted in a particular way based on the person’s character. While this can’t be used to prove that a person’s behavior at a certain time was consistent with his or her character, it can be used in some workplace investigations to prove intent, motive, or opportunity.
4. Circumstantial Evidence
Also known as indirect evidence, this type of evidence is used to infer something based on a series of facts separate from the fact the argument is trying to prove. It requires a deduction of facts from other facts that can be proven and, while not considered to be strong evidence, it can be relevant in a workplace investigation, which has a different burden of proof than a criminal investigation.
5. Demonstrative Evidence
An object or document is considered to be demonstrative evidence when it directly demonstrates a fact. It’s a common and reliable kind of evidence. Examples of this kind of evidence are photographs, video and audio recordings, charts, etc. In a workplace investigation, this could be an audio recording of someone’s harassing behavior or a photograph of offensive graffiti.
6. Digital Evidence
Digital evidence can be any sort of digital file from an electronic source. This includes email, text messages, instant messages, files and documents extracted from hard drives, electronic financial transactions, audio files, video files. Digital evidence can be found on any server or device that stores data, including some lesser-known sources such as home video game consoles, GPS sport watches and internet-enabled devices used in home automation. Digital evidence is often found through internet searches using open source intelligence (OSINT).
Challenges of digital evidence
Collecting digital evidence requires a skillset not always needed for physical evidence. There are many methods for extracting digital evidence from different devices and these methods, as well as the devices on which evidence is stored, change rapidly. Investigators need to either develope specific technical expertise or rely on experts to do the extraction for them.
Preserving digital evidence is also challenging because, unlike physical evidence, it can be altered or deleted remotely. Investigators need to be able to authenticate the evidence, and also provide documentation to prove its integrity.
7. Direct Evidence
The most powerful type of evidence, direct evidence requires no inference. The evidence alone is the proof. This could be the testimony of a witness who saw first-hand an incident of sexual harassment in the workplace.
8. Documentary Evidence
Most commonly considered to be written forms of proof, such as letters or wills, documentary evidence can also include other types of media, such as images, video or audio recordings, etc.
9. Exculpatory Evidence
This type of evidence can exonerate a defendant in a – usually criminal – case. Prosecutors and police are required to disclose to the defendant any exculpatory evidence they find or risk having the case dismissed.
How Should (and Shouldn’t) You Conduct a Workplace Investigation?
10. Forensic Evidence
Forensic Evidence is scientific evidence, such as DNA, trace evidence, fingerprints or ballistics reports, and can provide proof to establish a person’s guilt or innocence. Forensic evidence is generally considered to be strong and reliable evidence and alongside helping to convict criminals, its role in exonerating the innocent has been well documented. The term “forensic” means “for the courts”. Its use in workplace investigations is generally limited to serious cases that may end up in court.
11. Hearsay Evidence
Hearsay evidence consists of statements made by witnesses who are not present. While hearsay evidence is not admissible in court, it can be relevant and valuable in a workplace investigation where the burden of proof is less robust than in court.
12. Physical Evidence
As would be expected, evidence that is in the form of a tangible object, such as a firearm, fingerprints, rope purportedly used to strangle someone, or tire casts from a crime scene, is considered to be physical evidence. Physical evidence is also known as “real” or “material” evidence. It can be presented in court as an exhibit of a physical object, captured in still or moving images, described in text, audio or video or referred to in documents.
13. Prima Facie Evidence
Meaning “on its first appearance” this is evidence presented before a trial that is enough to prove something until it is successfully disproved or rebutted at trial. This is also called “presumptive evidence”.
14. Statistical Evidence
Evidence that uses numbers (or statistics) to support a position is called statistical evidence. This type of evidence is based on research or polls.
15. Testimonial Evidence
One of the most common forms of evidence, this is either spoken or written evidence given by a witness under oath. It can be gathered in court, at a deposition or through an affidavit.
zeffur: As you can evidently see above:
1. Dictionary definition: evidence: "that which tends to prove or disprove something; ground for belief; proof."
2. Achilles wrote: "Remember, what we're discussing here is evidence and not proof. Evidence, supposedly, gives us some reason--though not a compelling reason (i.e., proof)--to believe that a particular claim is true."
Is it any wonder why he is confused?? The reason for showing/offering evidence is to prove/disprove a claim/s. He would have you believe it's not for a compelling reason or proof that a claimed fact/s is/are true. He's obviously WRONG. The reason/purpose for offering evidence IS to attempt to prove/disprove a claim/fact is true/false.
AchillesSinatra: Ah, once more, boys and girls, Zeffur--a man of two books (the Bible and his prized dictionary)--has seen fit to lecture on topics he knows precisely nothing about.
Why, one can easily imagine Zeffur looking up "relativity" in his beloved dictionary, then--in the highest dudgeon--composing the following letter to Albert Einstein:
"The things you say about relativity do not agree with what my dictionary says. Therefore, you are not only WRONG but a dishonest nitwit to boot.
Mr Two Books"
Now, if evidence provides a compelling reason for belief (i.e. proof), as Zeffur would have us believe, we can only wonder why lawyers in court present Exhibit A, then Exhibit B, then Exhibit C . . . then Exhibit N. If evidence is indeed tantamount to proof, as Zeffur suggests, surely just one item-- Exhibit A, perhaps-- would be sufficient to prove the case?
Why do lawyers waste everyone's time by presenting ten (say) items of evidence when, on Zeffur's account, evidence provides a compelling reason for belief and thus one piece would be perfectly sufficient to do the trick?
And why is it that sometimes not even ten items of evidence do the trick: the jury remains unconvinced, and Murphy gets acquitted of the crime of which he was accused?
Clearly, then, neither a singularity nor a plurality of evidence invariably constitutes a compelling reason for belief. Clearly, then, Zeffur is talking shit again.
This being the science forum, however, the kind of evidence that interests us here specifically is scientific evidence. In earlier posts I mentioned three (among many) concepts of scientific evidence that have been suggested. Let's examine two of them and see how Zeffur's analysis stands up . . .
(Remember, Zeffur's claim is (see above) "The reason for showing/offering evidence is to prove/disprove a claim/s. He [Achilles] would have you believe it's not for a compelling reason or proof that a claimed fact/s is/are true." )
1. Hypothetico-deductive (H-D) confirmation.
On this account, any observation ENTAILED by a theory constitutes evidence for that theory.
So, for example, if our theory is "all ravens are black", then proponents of the H-D method regard the observation of any black raven as evidence to support that theory. Not even the most rabid H-D advocate, though, Zeffur's bs notwithstanding, would regard the observation of one black raven (= one piece of evidence), or even ten black ravens (= ten pieces of evidence), as a compelling reason--proof-- to believe that theory.
Perhaps the best man to read on H-D confirmation is Carl Hempel. Are you familiar with his work, Zeffur? I didn't think so.
2. Bayesian confirmation
On the (subjective) Bayesian account, anything that raises the prior probability one assigns to a theory constitutes evidence to support that theory.
So, for example, suppose our theory is "Zeffur will have sex with Miss Japan in his lifetime". We are all entitled to assign whatever prior probability we like (except zero or one) to this theory. I'd personally assign it a very low probability: say, 0.00001.
Now, as new evidence comes in, we adjust our prior probabilities according to the OBJECTIVE canons of Bayesian confirmation. Suppose new evidence comes to light that Zeffur is planning a vacation in Tokyo. I do the calculations and adjust my prior probability of 0.00001 to a posterior probability of 0.00002.
Given that my prior probability has been raised--even minusculely--then Zeffur's impending excursion to the Far East constitutes evidence for the theory that he will end up in the sack with Miss Japan. Evidence it is then, at least to the Bayesians, though I doubt very much any of us consider this a compelling reason (i.e. proof) to believe that Zeffur's oriental wet dreams will be fulfilled, even if we can wish him all the best. After all, it might finally shut the imbecile up for a while.
Perhaps the best man to read on the Bayesian concept of evidence is Colin Howson. Are you familiar with his work, Zeffur? I didn't think so.
Perhaps the best man to read on the topic of scientific evidence overall is Peter Achinstein. Are you familiar with his work, Zeffur? I didn't think so.
Conclusion: Why not ask Santa for a third book for Christmas to add to your collection?
zeffur: re: "AchillesSinatra: And why is it that sometimes not even ten items of evidence do the trick: the jury remains unconvinced, and Murphy gets acquitted of the crime of which he was accused?"
The reason is the same reason that most well informed people reject the evidence + suppositions that evolutioners offer--not all evidence is weighed equally & often times the accompanying suppositions have no solid basis or they are obviously untrue (but presented with the evidence in an attempt to confuse & sway belief as they would like the jurors to believe)--much like how evolutioners offer creative drawings of 'evolution' rather than real fossils & how they tell their imaginary stories about how & why life has 'evolved' on earth (which of course only works on simpletons who are unfamiliar with such tactics or on atheists who are inherently biased to desire an alternative to a designer/creator-based explanation).
Nevertheless, the "The reason for showing/offering evidence is to prove/disprove a claim/s". Whether or not the evidence offered is sufficient to prove/disprove a claim is true or not is for a jury to decide. The same thing applies to evolution in the court of public opinion. When they evaluate all of the verified evidence & assumptions/opinions & explanations offered, they decide for themselves whether or not all of that evidences & other information is valid/true--and in the case of evolution, most well informed people consider it rubbish. It's only considered valid/true to most atheist & other nitwits.
re: "Conclusion/Suggestion 2: Why not just stick to what you do best: muttering vacuous inanities such as "Truth is that which is true" and "Evidence is that which is evident"
There is no need for me to do that as you demonstrate quite well that you fill that role so much better than anyone else in these forums--well, maybe with the exception of BelgianStrider. Perhaps you can share that role with him?
re: "...almost forgot, and "Evolution is crap! Squawk!""
On that ^^ I certainly agree--evolution is pure rubbish!