The meaning of evidence

[Sherlock Holmes]

This thread is to discuss the meaning of the term "evidence" particularly with respect to claims made by evolution advocates.

The reason I started this thread is that I often see - what I regard as - a conflation of consistent with and evidence for. If we are to make reasonable inferences and maintain objectivity and avoid making assumption unwittingly then the more precisely we define "evidence" the better I think.

The biggest risk here is to imply that some observation P is evidence for X and only X, rather than evidence for X and Y or Z. Unless we are on our guard we can informally exclude reasonable possibilities Y and Z and so on. Now the observation P might well be evidence for X and only X, but unless that is soundly established we simply can't assume that.

If we mistakenly regard P as evidence for X and only X then we fall into the trap of believing that P can only be observed if X was the cause.

This is exemplified by an analogy I recently put together that I think warrants its own thread, so here it is:

Consider this jigsaw

None of the circles overlap, we can see this when we can see the totality of the jigsaw. But if we already believed for some reason or other, that they must overlap and we only had twenty random pieces and never see the rest, we could make up a jigsaw (theory) where we "fill in the blanks" so to speak and "show" that we sometimes have overlapping circles.

We'd be absolutely right too in saying the twenty pieces were consistent with an image that has overlapping circles, but we'd be dead wrong to say the twenty pieces are evidence of overlapping circles, because as we know, none of the circles actually do overlap.

So do you agree or not, there's a difference between observations that are evidence for some hypothesis vs consistent with some hypothesis and we should always be careful and make this distinction clear in our arguments?

[Sherlock Holmes]

These are examples of things said in this science oriented thread by people apparently having some knowledge of science, during what was supposed to be a scientific discussion, these are all examples of prejudice, dismissing what a person has to say on the basis of personal details.

H.R. Heinlein had the right idea. He wrote that there were two fallacies about experts. The first is that they know everything. The second is that everyone's opinion is as good as the next person's. When you see a layman writing about paleontology, and he gets support almost exclusively from people who are not trained in paleontology, that's a big tip-off.

I disagree, that's a serious error of judgment. If Meyers is proposing something that a majority of paleontologists are likely dispute then how does that prove that his argument is wrong? its pretty obvious that if you fundamentally question a system of thought then many of those who've trusted and invested in that system of thought might well be the last people to consider abandoning it. This is not how to evaluate scientific arguments or disagreements, absolutely terrible approach.

Evaluating arguments on the basis of the qualifications of the proponent is a poor way to do science,

When I decide whether or not to have a medical procedure, I put more weight on the opinion of my doctor than on the opinion of my barber. Go figure.

Surely that depends upon the barber's knowledge of medicine? if you knew he had an in-depth knowledge of some area then his opinion might be relevant.

that attitude is exactly what Galileo faced,

No, you have that wrong. Galileo was a scientist, who actually studied the heavens, and his critics were not. You have it exactly backwards. And the result of giving the ignorant a say in things they knew very little about, was not very good.

What did I get backwards? I said "that attitude is exactly what Galileo faced, that only the special elite class of the then experts were competent to discuss the cosmos" which is true. He did face that and the clergy were the established authority he clashed with. He (a dissenter) was attacked because an elite group (the clergy back then, the evolutionists today) could not tolerate being undermined, their authority questioned.

That is the same attitude I see here, no matter that you try to legitimize todays authority on the basis they are "scientists", rejecting a person because they question dogma is the pattern.

Only those who "understand" evolution are credible enough to discuss it, those who fundamentally question it are told they do not "understand" hence the dogma is self reinforcing, Kafka could have written a novel about this, perhaps his The Trial bears more than a passing resemblance...

Like some here, they thought everyone's opinion was as good as Galileo's and listened only to those they wanted to hear. They ignored Galileo, Kepler, Tycho, and Copernicus and went with guys who were so indoctrinated into Ptolemy's system that they would not even look into the telescope to see what was there.

Yes, elites will go to great lengths to suppress dissent, often attacking people for all sorts of reasons, sometimes even personal characteristics that have nothing to do with the views they are advocating.

But this is your call, if you're only willing to listen to people you want to hear from, go ahead.

Except I used to be an avowed atheist and evolution advocate and was until my late twenties, I have listened to all sides of these disputes for decades, unlike many who have only ever seen things from one vantage point.

[Difflugia]

I can't debate a person under these circumstances, sorry. I'm done with name calling and ad hominem and baseless accusations.

Of course. Mind the door.

[Sherlock Holmes]

I can't debate a person under these circumstances, sorry. I'm done with name calling and ad hominem and baseless accusations.

Of course. Mind the door.

What door? didn't you see? I removed the lock the door and the hinges, anyone can come and go as they please now, no matter their beliefs or qualifications.

[Jose Fly]

Sure this would be true if evolution of ever increasingly complex life were a reality but I see no evidence for that.

Depending on how one defines and measures "complexity", it's a directly observed fact.

What we see today is not bacteria in a lab becoming worms for example

That's a pretty ridiculous standard (and is a logical fallacy).

you believe with all your heart that this is possible and I understand it seems feasible when taken at face value but there's no evidence even the fossil record flies in the face of the belief, this is how I see things anyway. Insisting that observations made over a few years can serve as proof that extrapolations of this can take place over tens of millions of years is not scientifically testable.

Your opinion is noted.

How can you prove that a colony of bacteria will ever evolve into worms or jellyfish? sure you can argue it will, you can argue that it did in the past, you can extrapolate and so on but all you have are imperfectly understood processes whose long term behavior cannot be known.

I hope you're not under the mistaken impression that science "proves" things.

Have you never heard of tin whiskers?

A totally unanticipated metallurgical phenomenon that plagued electronics once, due to solder with tin in it. These "whiskers" just sprouted inexplicably like grass from the inner surfaces of transistors destroying satellite electronics and military kit.

Nobody ever had any idea that a simple inorganic element like tin could behave this way, and here you are assuming all sorts of stuff about how organic chemistry behaves over millions of years! Until these were encountered the possibility never crossed anyone's mind, unforeseen consequences - why do you think biochemistry has no unforeseen consequences like this?

I find your argument that because tin behaved in an unexpected way we therefore can't say how chemistry worked in the past to be bizarre.

I'll tell you, faith, belief, that's all you have you no more know how a bacterial colony will look in a million years than the metallurgists knew that tin can sometimes grow like grass!

Your opinion is noted. I always find it fascinating when I see creationists use the term "faith" as an attempted insult. Pretty amusing too.

[Jose Fly]

I already showed Jose how genetic engineering could be mistaken for common ancestry

No, I explained how the two are different and you ignored it.

[Sherlock Holmes]

Sure this would be true if evolution of ever increasingly complex life were a reality but I see no evidence for that.

Depending on how one defines and measures "complexity", it's a directly observed fact.

What we see today is not bacteria in a lab becoming worms for example

That's a pretty ridiculous standard (and is a logical fallacy).

you believe with all your heart that this is possible and I understand it seems feasible when taken at face value but there's no evidence even the fossil record flies in the face of the belief, this is how I see things anyway. Insisting that observations made over a few years can serve as proof that extrapolations of this can take place over tens of millions of years is not scientifically testable.

Your opinion is noted.

How can you prove that a colony of bacteria will ever evolve into worms or jellyfish? sure you can argue it will, you can argue that it did in the past, you can extrapolate and so on but all you have are imperfectly understood processes whose long term behavior cannot be known.

I hope you're not under the mistaken impression that science "proves" things.

Have you never heard of tin whiskers?

A totally unanticipated metallurgical phenomenon that plagued electronics once, due to solder with tin in it. These "whiskers" just sprouted inexplicably like grass from the inner surfaces of transistors destroying satellite electronics and military kit.

Nobody ever had any idea that a simple inorganic element like tin could behave this way, and here you are assuming all sorts of stuff about how organic chemistry behaves over millions of years! Until these were encountered the possibility never crossed anyone's mind, unforeseen consequences - why do you think biochemistry has no unforeseen consequences like this?

I find your argument that because tin behaved in an unexpected way we therefore can't say how chemistry worked in the past to be bizarre.

I'll tell you, faith, belief, that's all you have you no more know how a bacterial colony will look in a million years than the metallurgists knew that tin can sometimes grow like grass!

Your opinion is noted. I always find it fascinating when I see creationists use the term "faith" as an attempted insult. Pretty amusing too.

The point about the tin whiskers example is that there are sometimes unanticipated phenomena inherent in the long term behavior of systems. The tin whisker problem was first noticed in the 1940s despite the fact industry had used electroplating for over a century prior to that. The problem is often functionally fatal to certain kinds of electronic devices, rendering systems based upon them, unfit for purpose.

Proposing that behaviors we've observed in biological systems, cells, genetics and so on are sufficiently well understood at this time, to claim that there's no prospect whatsoever of similar unanticipated phenomena strikes me as wishful thinking, given real world examples like tin whiskers.

Unlike electronics, evolution advocates are extrapolating over much larger timeframes, hundreds of thousands or millions of years. If there are unanticipated problems that only emerge after say ten thousand years then clearly we will not know of them yet.

I do not see how one can demonstrate that the behavior of a bacteria colony (say) over a hundred thousand years, can be free of things that might disrupt evolutionary expectations unless one actually observes the colony for a hundred thousand years.

There could be any number of unforeseeable effects capable of thwarting evolution, we do not know, you do not know so on that basis I am skeptical to say the least.

[JoeyKnothead]

Sure, like I said you'll dismiss the book, I understand.

I saw you mention the book. I didn't see where you cited pertinent parts that show Meyers' intelligent design arguments stand to rigorous scrutiny.

The Discovery Institute's biases are well known. For someone who professes experience in these sorts of debates, you don't do yourself proud pointing to that bunch.

Well we need look no further than many of the posts here that have been derogatory to Meyers if we want clear examples of bias.
...

Okay, let's just stipulate those examples I snipped are biased against Meyers. Are they not correct though?

None of that offered examples from a / the Meyer's book, that we might trust his opinion on scientific matters. Nor does your claim of bias show Meyers ain't, as a member of the Discovery Institute, predisposed to draw his conclusions based on the intelligent design model.

These are examples of things said in this science oriented thread by people apparently having some knowledge of science, during what was supposed to be a scientific discussion, these are all examples of prejudice, dismissing what a person has to say on the basis of personal details.

I note you're not refuting those examples, but just calling em prejudiced.

Folks can be biased, and still tell the truth.

Once again, here's what Noam Chomsky says about this (emphasis mine)

In my own professional work I have touched on a variety of different fields. I’ve done work in mathematical linguistics, for example, without any professional credentials in mathematics; in this subject I am completely self-taught, and not very well taught. But I’ve often been invited by universities to speak on mathematical linguistics at mathematics seminars and colloquia. No one has ever asked me whether I have the appropriate credentials to speak on these subjects; the mathematicians couldn’t care less. What they want to know is what I have to say. No one has ever objected to my right to speak, asking whether I have a doctor’s degree in mathematics, or whether I have taken advanced courses in the subject. That would never have entered their minds. They want to know whether I am right or wrong, whether the subject is interesting or not, whether better approaches are possible. The talk dealt with the subject, not with my right to discuss it.

Math ain't paleontology or biology.

Nobody's saying Meyer ain't got a right, they're saying he ain't got "it" right.

Evaluating arguments on the basis of the qualifications of the proponent is a poor way to do science, that attitude is exactly what Galileo faced, that only the special elite class of the then experts were competent to discuss the cosmos.

Of course qualifications matter. I wouldn't trust an assistant chicken plucked to perform neurosurgery on me.

But this is your call, if you're only willing to listen to people you want to hear from, go ahead.

I'm 'hearing' from you.

That alone is sound indication I'll listen to someone, no matter how faulty their arguments.

[Jose Fly]

The point about the tin whiskers example is that there are sometimes unanticipated phenomena inherent in the long term behavior of systems.

And sometimes there aren't. That's why we examine each case individually.

Proposing that behaviors we've observed in biological systems, cells, genetics and so on are sufficiently well understood at this time, to claim that there's no prospect whatsoever of similar unanticipated phenomena strikes me as wishful thinking, given real world examples like tin whiskers.

Your opinion and fallacious argument are noted.

I do not see how one can demonstrate that the behavior of a bacteria colony (say) over a hundred thousand years, can be free of things that might disrupt evolutionary expectations unless one actually observes the colony for a hundred thousand years.

There could be any number of unforeseeable effects capable of thwarting evolution, we do not know, you do not know so on that basis I am skeptical to say the least.

Or there could be no such effects.

[The Barbarian]

H.R. Heinlein had the right idea. He wrote that there were two fallacies about experts. The first is that they know everything. The second is that everyone's opinion is as good as the next person's. When you see a layman writing about paleontology, and he gets support almost exclusively from people who are not trained in paleontology, that's a big tip-off.
[/quote]

I disagree, that's a serious error of judgment. If Meyers is proposing something that a majority of paleontologists are likely dispute then how does that prove that his argument is wrong?

If he's a philosopher (with a pre-existing bias against Darwinism) proposing something about paleontology that a majority of paleontologists, including a number of his fellow anti-Darwnians, disagree with, that's strong evidence that he's wrong. Like many other creationists, he's trusted and invested in creationism, so it's hard for him to abandon it.

its pretty obvious that if you fundamentally question a system of thought then many of those who've trusted and invested in that system of thought might well be the last people to consider abandoning it.

Yep.

This is not how to evaluate scientific arguments or disagreements, absolutely terrible approach.

When I was contemplating the removal of my gall bladder, I considered the consensus of intermal medicine specialists, ignoring what any philosophers might have thought. Seems like a reasonable way to go about it.

Evaluating arguments on the basis of the qualifications of the proponent is a poor way to do science,

When I decide whether or not to have a medical procedure, I put more weight on the opinion of my doctor than on the opinion of my barber. Go figure.

Surely that depends upon the barber's knowledge of medicine? if you knew he had an in-depth knowledge of some area then his opinion might be relevant.

Sorry, I'll go with people who have demonstrated a knowledge of medicine. Feel free to let your barber guide you if you like.

that attitude is exactly what Galileo faced,

No, you have that wrong. Galileo was a scientist, who actually studied the heavens, and his critics were not. You have it exactly backwards. And the result of giving the ignorant a say in things they knew very little about, was not very good.

What did I get backwards?

Galileo, Copernicus, Kepler, and so on, actually studied the skies, had adequate data to make conclusions, an were qualified to say. On the other hand, they were opposed by men who had no such experience or data, who merely were so invested in a religiously-derived idea about the skies that they were unable to even look in the telescope to see. The medieval equivalent of creationists.

I said "that attitude is exactly what Galileo faced, that only the special elite class of the then experts were competent to discuss the cosmos" which is true.

The experts all agreed with him (although Tycho may have had some reservations in some things). The "barbers" were the ones who didn't agree with him. They had no expertise, no data. They merely went with their religious presuppositions, just as creationists and IDers do today.

Only those who "understand" evolution are credible enough to discuss it,

Well, to be fair, that's true of anything. If you don't understand it, you're not going to be able to intelligently discuss it.

Often creationists claim that scientists lack "discernment" and that only people with the right religious beliefs can properly understand the doctrine of creationism. Those who fundamentally question it are told they do not "understand" hence the dogma is self reinforcing, Kafka could have written a novel about this. The Scopes Trial did indeed have Kafkaesque moments.

Like some here, they thought everyone's opinion was as good as Galileo's and listened only to those they wanted to hear. They ignored Galileo, Kepler, Tycho, and Copernicus and went with guys who were so indoctrinated into Ptolemy's system that they would not even look into the telescope to see what was there.

But this is your call, if you're only willing to listen to people you want to hear from, go ahead.

(claim to have been an atheist and an "evolutionist")

Wrong about one thing and right about another. And then you switched. Seems odd, but a lot of internet creationists tell that story, so...

[Sherlock Holmes]

If he's a philosopher (with a pre-existing bias against Darwinism) proposing something about paleontology that a majority of paleontologists, including a number of his fellow anti-Darwnians, disagree with, that's strong evidence that he's wrong. Like many other creationists, he's trusted and invested in creationism, so it's hard for him to abandon it.

Well this belief that the popularity of an idea is somehow a reliable indication of its veracity is a very common misunderstanding. That its fallacious is easily shown by the obvious fact that popular ideas were at one time unpopular, before they became popular.

Science is littered too with examples of once popular accepted beliefs that are now no longer regarded as valid, one example being the almost universal acceptance of the luminiferous aether hypothesis in physics until the early 20th century.

Science is not a popularity contest, the relative veracity of competing ideas is not established by assessing their relative popularity, well it never used to be when I was younger, maybe things have changed.