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?

[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.

[JoeyKnothead]

Well I for one see no merit in playing tennis with quotes,

Probably a bad idea for you to have served first, then.

Lol

I showed JoeyKnothead that Meyer's book was well received by numerous accredited scientists and that's pretty much the case.

I notice only one paleontologist, and he actually disagrees with Meyer. That matters.

The one guy who might can help, can't. Typical of creationists attempts to point to credible scientists, only to find they disagree.

Falk's opinion is simply that - an opinion

An informed opinion by someone who actually has credentials. Meyer, as you know, is a philosopher. His opinion is simply that. A layman's opinion.

And predisposed to reject science over "God did it".

- as you can see numerous others praise the book, so what can we conclude?

Meyer's layman opinion on paleontology is much more popular with non-paleontologists than with paleontologists. Which shouldn't be a surprise to you.

Philosophy does not provide a solid enough groundwork to set in on paleontology.

Might as well ask me how to hush up the pretty thing.

I think the rational thing to conclude here is that we obviously have a true controversy

Not surprising. If you picked almost any technical field, you'd find more dissenting opinions from people who weren't actually in the field than from those who actually know what they're talking about.

Yup.

not the picture perfect fairy tale tree of life

If you actually believe that, you know far less about evolutionary theory than I thought. There are lively discussions and controversies about all sorts of things in evolution.

It never fails to chuckle me when theists carry on about fairy tales.

that some teachers and authors would like to palm off on the gullible, the uncritical.

Judging by your contribution and cites, it is more likely a problem of the uninformed.

Or the dastardly.

[Difflugia]

You are quite wrong to say "you've also steadfastly refused to engage with molecular data" as this post proves beyond doubt, here's my remarks from that post made exactly one month ago (Feb 28) discussing the Cambrian fossil record:

I see, so we have no actual genetic material from the Cambrian at all.

Genetic similarities are not evidence of common ancestry either, they are consistent with common ancestry if we assume evolution occurs but can't serve as evidence for evolution when evolution is predicated upon it. I've seen people make this logical error before, its understandable too because the incessant "evolution is a fact" has been drummed into all of since we were knee high to a grasshopper.

Does that really look to you as me "steadfastly refusing to engage"?

Yes. A handwaving, unsupported dismissal isn't engaging.

So are you admitting here that the fossil record is too discontinuous as it stands to serve as "evidence for" evolution of the Cambrians? and that we must bolster it with additional arguments, like observations about DNA?

No. The fossil record overall is strong evidence of common descent. I'm "admitting" that because fossils are necessarily snapshots into a process, whatever that process is, one could posit that some quantized process is responsible for relatively large morphological differences that we see rather than the otherwise apparent accumulation of small ones. "Bolstering" the fossil evidence with DNA evidence means that the premise of large morphological leaps is unfounded and we no longer even have to consider the otherwise implausible mechanism of an omnipotent and intelligent, yet undetectable superbeing.

By "we" you mean those scientific investigators who believe in evolution?

Yes.

I've said before that I have no idea how the Cambrian animals arose, to what degree God "participated", I have not speculated on that, only that the event represented by the Cambrian fossil record is truly extraordinary and - IMHO - incompatible with claims of gradualism.

That's your mistake. The period described as "Cambrian" lasted over fifty million years. The entire radiation of placental mammals occurred within a similar time frame, for example. There was plenty of time for large-scale morphological change.

Now with respect to molecular data, I do not see how that can help reduce the magnitude of the Cambrian event, it is as if you are saying "yes the Cambrian is crazy, a lot did happen in a short space of time, but that doesn't matter because we have this indirect molecular evidence".

No, I'm saying that the molecular evidence makes it that much more obvious that positing an omnipotent, yet undetectable being is special pleading. A few details of your statement deserve extra responses, though:

• The metazoan radiation wasn't limited to the Cambrian, but was underway by the Ediacaran, at least tripling the amount of time for the diversity we see by the end of the Cambrian.
• This period may be considered relatively short compared to periods of morphological stability before and since, but the prior stability was due to a lack of metazoa. The newly evolving metazoa were forging their own ecological niches that were previously uninhabited. Stability following the Cambrian was because most of these new niches were now filled, meaning that morphology changes had to take place in inhabited spaces with much more competition.
• The molecular evidence isn't "indirect" any more than fossil or any other evidence. Both fossil and molecular data are measurements collected from individual organisms showing the same kinds of relationships. Molecular data are harder to interpret by nonspecialists, but make up for it with orders of magnitude higher resolution.

Just to clarify, is your claim that special creation events are limited to the Cambrian and then evolution took over? You seem to want to separate the Cambrian data from anything later, but that's only valid if you're claiming that there are two independent mechanisms responsible for what is otherwise the same set of patterns.

You see IF the Cambrian was "supernaturally" induced in some way THEN any purported molecular evidence is irrelevant, that too might also have a supernatural explanation, for example using tried and test molecular mechanisms to design and construct different organisms.

Last Thursdayism. Got it.

The prevalence of common traits in molecular data across diverse species does not prove that that commonality is due to the long term consequences of inheritance, yes it is consistent with that, but that's the very thing were differentiating here.

Your counter mechanism is omnipotent magic. If your argument is that God can do whatever He wants even if it looks exactly like something else, then you're just claiming that special pleading is a legitimate form of evidence.

[The Barbarian]

Genetic similarities are not evidence of common ancestry either,

We can test your assumption by comparing DNA of organisms of known ancestry. Turns out that genetic data is evidence of common ancestry. It's been directly confirmed.

they are consistent with common ancestry if we assume evolution occurs

As direct testing has shown DNA does indeed indicate common ancestry. No point in denial. Your logical error is to assume that we didn't confirm the fact with known ancestors. You just started with the assumption that evolution can't be true, and therefore the evidence cannot be.

I've seen people make this logical error before, its understandable too because the incessant "evolution false" has been drummed into many of us since we were knee high to a grasshopper.

So are you admitting here that the fossil record is too discontinuous as it stands to serve as "evidence for" evolution of the Cambrians?

As you learned earlier, there is abundant evidence in the fossil record showing transitions from Precambrian to Cambrian fossils. No point in denying that fact, either.

and that we must bolster it with additional arguments, like observations about DNA?

You learned that informed and honest YE creationists admit that there is very strong evidence for macroevolutionary theory in the fossil record, including the Cambrian. Would you like to see that, again?

That's your mistake. The period described as "Cambrian" lasted over fifty million years. The entire radiation of placental mammals occurred within a similar time frame, for example. There was plenty of time for large-scale morphological change.

Do you really think the Cambrian showed no evolutionary trends? Seriously?



Other groups underwent similar evolutionary change. Why not take a little time out and learn about it, instead of copying from other creationists?

[Sherlock Holmes]

You are quite wrong to say "you've also steadfastly refused to engage with molecular data" as this post proves beyond doubt, here's my remarks from that post made exactly one month ago (Feb 28) discussing the Cambrian fossil record:

I see, so we have no actual genetic material from the Cambrian at all.

Genetic similarities are not evidence of common ancestry either, they are consistent with common ancestry if we assume evolution occurs but can't serve as evidence for evolution when evolution is predicated upon it. I've seen people make this logical error before, its understandable too because the incessant "evolution is a fact" has been drummed into all of since we were knee high to a grasshopper.

Does that really look to you as me "steadfastly refusing to engage"?

Yes. A handwaving, unsupported dismissal isn't engaging.

I'm sorry you accuse of me refusing to engage, I showed a clear example from a month ago of my responding to the very thing you said I didn't yet you persist in maintaining the accusation, the evidence is right there before your eyes yet you deny.

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

[Sherlock Holmes]

Genetic similarities are not evidence of common ancestry either,

We can test your assumption by comparing DNA of organisms of known ancestry. Turns out that genetic data is evidence of common ancestry. It's been directly confirmed.

they are consistent with common ancestry if we assume evolution occurs

As direct testing has shown DNA does indeed indicate common ancestry. No point in denial. Your logical error is to assume that we didn't confirm the fact with known ancestors. You just started with the assumption that evolution can't be true, and therefore the evidence cannot be.

I've seen people make this logical error before, its understandable too because the incessant "evolution false" has been drummed into many of us since we were knee high to a grasshopper.

So are you admitting here that the fossil record is too discontinuous as it stands to serve as "evidence for" evolution of the Cambrians?

As you learned earlier, there is abundant evidence in the fossil record showing transitions from Precambrian to Cambrian fossils. No point in denying that fact, either.

and that we must bolster it with additional arguments, like observations about DNA?

You learned that informed and honest YE creationists admit that there is very strong evidence for macroevolutionary theory in the fossil record, including the Cambrian. Would you like to see that, again?

That's your mistake. The period described as "Cambrian" lasted over fifty million years. The entire radiation of placental mammals occurred within a similar time frame, for example. There was plenty of time for large-scale morphological change.

Do you really think the Cambrian showed no evolutionary trends? Seriously?



Other groups underwent similar evolutionary change. Why not take a little time out and learn about it, instead of copying from other creationists?

I already showed Jose how genetic engineering could be mistaken for common ancestry, so on that basis alone it is clear that presence of similarities is not proof of common ancestry, there is at least one other way we know that similarities can be found: intelligent manipulation of DNA.

[Sherlock Holmes]

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.

"An informed opinion by someone who actually has credentials. Meyer, as you know, is a philosopher. His opinion is simply that. A layman's opinion."
"As I said, Meyers has PhDs in fields not directly pertinent to the stuff he seeks to fuss about."
"Philosophy does not provide a solid enough groundwork to set in on paleontology."
"Meyers has PhDs in History and Philosophy of Science. Hardly the guy we wanna trust when it comes to such areas as paleontology and biology."
"his credibility in science is questionable at best."
"Meyer, like most of the other Fellows of the Discovery Institute are primarily making religious/philosophical positions, to be disguised as science."

and on and on it goes.

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.

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.

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.

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

[The Barbarian]

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

I'm pretty sure "genetic engineering" wasn't done on Neandertals and other human ancestors, or all the other wildlife we have with us. That's rather flimsy straw to be grabbing onto.

[Sherlock Holmes]

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

I'm pretty sure "genetic engineering" wasn't done on Neandertals and other human ancestors, or all the other wildlife we have with us. That's rather flimsy straw to be grabbing onto.

I only stated what I think is a pretty undisputed fact, commonality is not incontrovertible proof of common ancestry, just because you know of no other mechanism does not prove that there is no other mechanism. I've seen these kinds of fallacious arguments before when debating evolutionists.

[The Barbarian]

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.

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.

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.

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.