Specifically, what is the evidence for common descent?(Not quite) famously, Darwin mused about the similarities of taxonomic hierarchies in linguistics and biology and asserted that the hierarchies must ultimately point to common descent. (Chapter XIV, On the Origin of Species) That’s common descent as distinguished from microevolution.
The linguistic equivalent is the single origin of all languages (eminently unproven and deemed unprovable) as distinguished from a language family (with demonstrable relevant organic shared features).
Darwinists are welcome to present their evidence. From Rumraket, we have the observation that all organisms can reproduce, “Nesting hierarchies are evidence of common descent if you know that the entities sorted into hierarchies can reproduce themselves. And that particular fact is true of all living organisms.” Good start.
From Joe Felsenstein we have the doubt that the border between micro- and macroevolution can be determined, “OK, so for you the boundary between Macro/Micro is somewhere above the species level. How far above? Could all sparrows be the same “kind”? All birds?” Not very promising.
From Alan Fox, “Darwin predicted heritable traits. Later discoveries confirmed his prediction.” Questions: Which heritable traits specifically? Was there a principled improvement over Mendel? And how does this lend credence to common descent?
Thanks to all contributors.
Inferring plylogenies is still based on inference which is based on conclusions already made.
Thats the rub.
Thats what MODERN creationism attacks, draws blood, and is not refuted well.
Why not?
Your lkist for common descent evidence of biological entities does not invlude any biological processes. only results after biological processes.
Where is the biology??
Biogeographic?! That has nothing to do with common descent investigation surely!
Fossils are just snapshops of biology and any relationship is just speculation and entirely based on deposition based on geology conclusions. More inference!
Development9unsure what that means)
Present day morphology, i think you mean comparative anatomy is after the fact again. It does not suggest common descent where leaps of difference are involved.
Molecues(Dna? ) again is just the same lines of reasoning used in comparative anatomy.
Its all reasoning, inferring, without biological evidence whatsoever.
SO another inference easily supplies another option and nullify’s the common descent option right away.
This is not scientific procedure in common descent evidence claims.
What is the top three evidence, from biological process information, to conclude common descent is the origin of biology on earth??
None was presented in your post and why do you think you did??
Common design works better then common descent. so is that also scientific evidence for itself?
your side would say NO!!
I could make this case before any audience and be persuasive for heaps of them.
creationists got a good point here.
Standards for biology evidence is the thread name.
A little off thread but species is not well defined or just more error from old school biology.
Nature, whatever the mechanism, does not recognize species.
all nature does is bring change to populations. WHATever the mechanism.
So a population looking slightly/or a lot different from another population only means there was that much change.
There is no threshold that must be crossed for a NEW species to have been created and now exists in time and space.
Whether the segregated populations can reproduce or not is irrelevant to the natures mechanism(s0 in changing populations.
so species do not exist. it is a old school wrong classification.
In fact evolutionism should be preaching this. There should be no finished products but only variation and so no micro/macro/species concepts.
Species should be dropped from progressive biological research OR say the very segregated different looking people groups also are species. They don’t say this but invoke whether segregated populations can reproduce or not etc etc.
its just careless thinking in the small circles that only in our day is being fixed and likewise evolutionary biology is being destroyed in our time.
Allan Miller,
I would doubt anyone would disagree that descent with modification has been observed by all. Isn’t the debate how many separate trees exist?
The term “biology” here refers to a subject so broad it makes it impossible to give a glib answer to that question. It’s not even clear what you mean by a “standard of evidence”, much less how it can be universally applied to all questions that can be posed within biology. Can you give an example?
Different questions in biology are assessed by different methods, and the “standards of evidence”, assuming I can sort of guess what you mean by that, between them can’t be directly compared. So there isn’t really one standard of evidence in biology.
What blue whales weigh, on average, is an empirical question in biology. What is the standard of evidence for that? Well first of all I wonder how blue whales masses are even estimated. From historical whaling or something? I guess the numbers come with error bars.
How many butteflies of some particular species live in some particular geographical area? This requires an entirely different method to investigate, than blue whale body mass. Are the standards of evidence the same for both? I don’t actually know. I doubt it would even make sense to apply an identical standard to both. At the very least, the standard has to fit the method and the tools we have. It doesn’t make sense, for example, to demand that blue whale body mass is known to the microgramme scale, when equipment for doing measurements of blue whale body mass simply cannot measure it to that level of accuracy.
I think what you want to ask is a much more specific question. You want to know how certain scientists are, that the theory of universal common descent is true, and you want to know why they’re that certain? Is that correct?
Mung,
Possibly, but I think it reasonable of me to ask where specifically the issue lies.
My general air of superiority.
Not in my book. I thought you were going to go for something like my use of the word ‘copy’; this arrow falls well short. It’s standard usage, anyway. Common descent is the term used in the OP, and well understood to refer to an actual thing. Common ancestors literally are ancestral, and the descendants of such common ancestors literally are descendants. What’s the non-metaphorical term?
colewd,
I dare say, but you asked me what my definition of evolution was.
Yes, and the evidence is for 1.
Or perhaps a related question might be, suppose we discover life on one of Jupiter or Saturn’s moons, Enceladus or Europa. We discover there is a diversity of life there and then the question becomes, does the diversity of life on Europa (say) share common descent? What would the standard of evidence be where a consensus of most working biologists would form?
Well, if those organisms have DNA, or a similar genetic polymer, then my understanding is that provided we have the means to discover their genetic code and sequence their genomes, understand their biochemistry and method of reproduction, we could do what has been done for life as we know it here on Earth. Try to sequence whatever key genes we find, and submit them to tests for phylogenetic signal. The same could possibly be done for morphology, anatomy and so on, provided we’re not just talking about single-celled life that all looks virtually identical in microscopes. Basically, we could try to categorize and group them by attributes and see if there is a tree-pattern produced. And if there is, such a tree-pattern should correlate with a tree-pattern from their genetic data.
So what is the “standard of evidence” for the detection of phylogenetic signal? Read Theobald:http://www.talkorigins.org/faqs/comdesc/section1.html#nested_hierarchy
Dontcha know, a word can only have one and only one true meaning.
Allan Miller,
A bold assertion. 🙂
colewd,
It is still where the evidence points. May I introduce you to a paper by Douglas Theobald … ?
Allan Miller,
I am interested more in your arguments. As Erik has discussed, common descent is a claim about transitions not similarities.
You could start with the prokaryotic to eukaryotic transition. If this does not work you are up to 2 trees. If the failure continues to address single cell eukaryotic to multicellular transition then we are up to 3. If again you stumble to explain the origin of vertebrates we arrive at 4 with no end in sight.
colewd,
If that’s what he said, he’s wrong. What about the Common and Spotted Sandpipers? Do we need an account of the transition from their common ancestor before we can infer common descent?
It was bold in 1859, as was the claim for an ancient earth.
Allan Miller,
You can infer all day long. How would you test the hypothesis?
It’s neither. It’s a claim about descent. It’s descent that implies transitions, not transitions that imply descent. You have it entirely backward.
Because the data show that prokaryotes and eukaryotes are related by descent, there must have been a transition from some ancestral condition to each of the modern conditions. Now of course we know that an important part of the transition in eukaryotes was an event of endosymbiosis, in which a eubacterial endocellular parasite became a mitochondrion. But that, contrary to your notions, is not evidence of common descent of eukarotes and prokaryotes. It is evidence of common descent of all eukaryotes, though.
Because the data show that unicellular and multicellular eukaryotes are related by common descent, there must have been several transitions from unicellularity (the ancestral condition) to multicellularity in various lineages. If you’re interested in intermediates, I direct you attention to Volvox and Dictyostelium. Intercellular signalling and adhesion within clonal populations was clearly involved. But that, contrary to your notions, is not evidence of common descent of unicellular and multicellular eukaryotes. It is evidence of common descent within the separate multicellular lineages, though.
Because the data show that vertebrates and other chordates are related by common descent, there must have been a transition from invertebrate to vertebrate chordates. And in fact there are a great many intermediate forms, from both fossil and extant species. Cephalochordates have notochords as skeletal support, nothing else. Lampreys have cartilaginous arcualia in addition. Dermal bone is attested from the Late Cambrian. Perichondral bone by the Silurian at the latest. Cartilage replacement bone came somewhat later, perhaps as late as the Devonian. Now those actually are some of the evidence for common descent of vertebrates, as the transition to what you presumably imagine are vertebrate charactes (vertebrae) arose within vertebrates.
To sum up: you are focused on the wrong evidence in the wrong way, and will never understand the evidence for common descent until you change that focus.
colewd,
Testing the inference is testing the hypothesis. The inference comes after examining the data, not before – a sequence of events with which you may be unfamiliar.
Actually, what he said, if none too clearly, was that the similarities that could theoretically indicate universal common descent in languages have not been found. The problem is that the sort of evidence (the proper patterns of similarities) that does exist for universal common descent in biology does not exist for languages. But if it did, it would be telling evidence for universal common descent of languages.
So while he’s inconsistent, by no means was he arguing against common descent being indicated by the right patterns of derivative similarities. For language that is his standard, for biology, well, he just doesn’t like evolution, like you.
Glen Davidson
You have no idea how science works. You don’t know what “infer” means. You don’t know what “test” means. All science is inference from data. A test, depending on what you mean by that, would add data to either strengthen or weaken an inference, or examine the degree to which existing data are decisive, or both. In phylogenetics, the main tests would be the fit of the data to alternative hypotheses and the consilience among different sets of data. I think you imagine that we must observe a squirrel transform into an acorn in the laboratory.
Allan Miller,
I agree with you that the inference comes from examining the data. Testing the inference is testing the hypothesis.
So how do you test that a transition occurred from reproduction over time in an isolated population?
,
colewd,
You tell me. Given two near-identical sequences in two genomes (Common and Spotted Sandpipers), what mechanisms could lead to this remarkable identity? I can think of two basic ones, both rooted in template copying of DNA – vertical inheritance and lateral transfer.
The latter is much less common, per generation, and cannot sensibly affect the entire genome at once, so the former is the more likely for any given sequence. If you have sequence identity, you have evidence of genetic continuity, and hence that a ‘transition occurred’.
Can you think of any other cause of sequence identity? What would lead us to prefer it, and reject genetic continuity?
Allan Miller,
I agree sequence identity is a reasonable test at this point. At what point of sequence dissimilarity do you reject the common descent hypothesis?
colewd,
You can’t reject it that way. After all, even with ‘true’ common descent, there must come a point with ongoing divergence where all relatedness signal is lost. But, if you had an alternative hypothesis, one might prefer it over common descent if it fit the data better.
You might have a null hypothesis, that the sequences were not related. You can reject that, by finding that their similarity is above a threshold, using similar statistical methods to those used elsewhere in science when comparing deviations from chance expectations. One would need to be careful to score runs of identity – significant clustering is not to be expected in a random dataset, but can give a significant score even when bitwise alignment is a ‘random background’ 25%.
Allan Miller,
Based on Dr. Harshman’s comment the DNA sequence variation among all humans is about .1%. This is over 200k years and currently about 7 billion people. It does not seem like the variation to make a transition is being generated as the genetic repair mechanisms are very powerful. As we sequence more data it will be interesting to see if this level of variation is similar among species. Thoughts?
No, the sequence variation between two arbitrarily chosen humans is about .1%; that isn’t at all the same as the “sequence variation among all humans”. But perhaps it’s what you meant to say. I have no idea what you mean by “the variation to make a transition”, but I suspect your misconceptions about evolution feature in it somewhere, as they do in your mention of genetic repair mechanisms. Many species (the two chimp species, for example) have much more genetic variation than we do, and many species (cheetahs, for example) have much less. The difference between species is typically much greater, but that depends largely on how long they’ve been separated. Recent species can show less variation between them than within most species, as speciation doesn’t depend in any way on gross sequence divergence.
colewd,
The present population size of humans, and the variation in it, is not much of a guide. The human race has expanded massively relatively recently, but the mutation rate and fixation rates are insufficient to generate the variation expected of such a population in long-term equilibrium. By the same token, population crashes have a marked effect on the variation that passes through the bottleneck. It appears that chimp populations have had less bottlenecking than human ones.
Mutation rates can be measured though, by various means. Typically there are of the order of 60 to 130 mutations in offspring that are not in either parent. Assuming most of them to be neutral, when one looks at the genetic difference between humans and chimps, the rate appears to be enough to generate the observed divergence over 6-7 million years.
And, one still has the enormous amount that has not changed to account for. This remains a massive strike in favour of common descent.
Colewd doesn’t know what clustering means in this context. Or what a random data set is. Or what a significance score is. Possibly not even what is meant by a bitwise alignment. Or a random background. Or why it would be expected to be 25% for random DNA sequence .
I’m 99.9% confident he finds that whole sentence virtually incomprehensible.
Rumraket,
Heh heh. Rereading, it does rather come across as technobabble!
Anyway, that isn’t how it works. Analysis has two steps: first, alignment; then, comparison of aligned sets of sequences site by site (on a tree, using some model of evolution, blah blah blah). The runs of sequence would be helpful in the first step. But the comparison must assume that all sites aligned to each other are homologous positions, and that a difference results from base substitution(s). The fact that random alignments will be 25% similar is something that needs to be taken into account if trying to abstract genetic distances, but is not really relevant to phylogenetic analysis.
Allan Miller,
On what basis are you confident that mutation rate estimates are accurate at this point?
John Harshman,
How does this compare to the human number of .1%? For cheetahs and chimps?
colewd,
Independent methods end up in the same ball park, and correlate with the DNA polymerase error rate in vitro, adjusted for mismatch repair.
John Harshman,
Does a run of 10 contiguous aligned bases not tend towards a higher score than the same 10 broken into 3 separate groups? (Assuming overall length in which the alignments are embedded is the same).
Just occurred to me that perhaps there’s a little game we could play to demonstrate how common descent is inferred, and how phylogenetic trees are built.
The idea is to have our local IDists make up a few data sets, as in some more or less simple sequences representing genomes, some arranged in a nested hierarchy and some others not forming a binary tree. If we can tell them which ones form a nested hierarchy (and from what tree they got the data from), and which don’t, that should prove that the CD inference works
ETA: They should only reveal the upper level of the tree, representing extant genomes.
This is the sort of thing you could easily look up and I have no strong need to do it for you.
Not sure what you refer to by “score”, but if you mean the likelihood or parsimony score by which one tree is judged better or worse than another, then no. Each site contributes to the score independently.
Interesting exercise, but I doubt any of them would be capable of it.
John Harshman,
OK, fair enough.
John Harshman,
Despite the preponderance of software types in the ID movement who could knock up a program in minutes.
They will not use their programming skills for evilution.
Glen Davidson
This sort of simulation is already quite straightforward to do with existing tools. No real programming required.
Are you saying that genome data forming a nested hierarchy is sufficient to infer common descent?
Let’s say these are made-up data sets representing genomes, just as you requested, nested hierarchies galore http://www.nature.com/nature/journal/v473/n7345/images/nature09923-f1.2.jpg What do you do with it? How do you infer common descent?
Evidence such as?
Again you look like saying that a tree-pattern by itself is sufficient. Just like Darwin did based on morphology.
And what’s so special about “phylogenetic signal”? https://doi.org/10.1080/10635150802302427
Looks like “phylogenetic signal” is just a way of saying, by statistical measure, how much of a pattern the pattern is. Eerily reminiscent of IDist FIASCO saying how much of a design the design is.
FYI, statistics does not demonstrate causal links. Never did, never will. You can statistically calculate probable causes only after you know by other means that such-and-such is a cause of such-and-such. There may always be an amazing density of acorns around oaks, but no amount of this data proves that acorns come from oak. You actually have to look up the oak and study the oak itself to verify that it indeed spawns acorns. Because merely by statistics it might be like cattle and mosquitoes who tend to keep company to each other.
This one is pretty cool, actually, and should be mentioned more often. It’s a strong point for you. Even though it’s consistent also with the “creation plan” perspective that Darwin derided. Namely, a plan would be harmonious overall, otherwise it’s hardly a plan.
Erik,
You are pitiful.
The very first comment in this thread bears repeating:
Get off your ass and do some work instead of asking to be spoon fed.
keiths,
As if these posts did not happen. Since you failed to respond, I stopped showing to you how much I have read. I’ve taken note of that website and a bunch of other material by now, but you will of course continue to ignore this. Stop pretending that you care.
Erik,
If you actually understood Theobald, you wouldn’t be asking the things that you’re asking, and you wouldn’t be writing things like this:
Actually read Theobald. The whole thing. If you still don’t understand it, read it again to see if it clicks the second time. Make an effort first. Then come to us with your questions.
No, not by itself. But for things that inexorably make tree patterns over multiple generations, yes.
Yes. But, you forget that we also expect the pattern. The pattern is a prediction of a particular hypothesis. So we look for the pattern, as in we look for phylogenetic signal, as an observational test of the prediction.
Nothing demonstrates causal links (assuming you mean demonstrate means some sort of “proof” that can’t be doubted). It’s ALL inference and induction. If I stand next to you and say “hand me a cup of coffee”, and I observe you give me a cup of coffee, have I demonstrated a causal link between me telling you to give me the coffee and you doing so? No, I actually haven’t. Why not? Well to pick an example, you could be deaf, or have head phones plugged in and listening to loud music thus not being able to hear me, and by accident have decided to give me the cup following me asking for it. In other words, it could be a coincidence.
There isn’t any causal link demonstrated. So instead, what we can do is say that it is unlikely that you would coincidentally decide to give me coffee after me asking for me. And if it happens multiple times, that just makes it ever more unlikely that it is a coincidence. So with enough data points, it becomes increasinly more difficult to argue that there is no causal link. It will always remain an inference, not a deductive proof that A caused B, just because B followed A in time. But that’s really just the unavoidable nature of inference and induction. Despite it’s deductively unprovable nature, science works. Inference and induction are useful tools.
No, but demanding proof in the sense of direct observation is a standard of evidence no method that tries to assess past historical events can ever satisfy. Say goodbye to all of history. You’re now completely ignorant of everything that has happened before your first memory.
You either accept the method of inference or you don’t. If you accept it, you’re going to have to explain why you reject it in this particular case.
To pick an example, take the inference that archeological digs that contain old documents were written by humans that lived in the past.
No amount of people writing documents in the here and now, demonstrates that a historical document unearthed by archeologists were in fact written by humans. The question becomes, what the hell else would make written documents? It could be written by aliens. Or have by some unfathomable statistical fluke randomly assembled from soil-atoms. But those seem less likely than the hypothesis that humans wrote them. You infer on the basis of the observed. It is an observed fact that humans write documents. So it is reasonable to infer, that documents unearthed in archeological digs, were written by humans.
It’s like that with tree patterns and common descent. We observe that the evolutionary process produces tree-patterns over generations in the here and now. So when we discover tree patterns into which all of present and past biodiversity can be sorted, we infer it was produced by the same evolutionary process observed in the here and now. We can’t “prove” or “demonstrate” that it did, because we can’t travel in time and directly observe it. But is it reasonable to even demand this?
What does Archeopteryx have to do with an “overall harmonious plan”? What is that, even?
Dave Carlson,
It’s true, you could do it with a photocopier and a biro.
I’m fully aware that the expectation of a pattern follows given a particular hypothesis. Such as the hypothesis of a creation plan. Or ID theory. Is this how you intended to come across?
I see.
Which particular case are you talking about? Is universal common descent the same particular case as the common ancestor of mutated fruitflies?
The relevant analogy is as follows: Whether writing originated at one single place and spread on from there or it originated at multiple places independently. The evidence does not justify the assumption that there was one single place of origin.
Yes, writing was most definitely invented by humans, but it does not follow that it originated with a single person single-handedly. Insofar as writing is (meant for) communication, it took cooperation to invent it and to stabilize the invention. And there were, as far as can be determined by evidence, several independent instances of such invention.
Still at square one. What is the evidence for common descent?
You really should read some Darwin. He makes it abundantly clear what “creation plan” is. In part, On the origin of Species is a debate against biologists who see themselves as discovering a “creation plan” in nature, such as in Chapter II when Darwin discusses the different points of view how to define species.
What it has to do with Archeopteryx? Archeopteryx would be a prediction if it fits the overall scheme of things while this sort of species hadn’t been found yet. It so happens that it fits both the scheme of evolution and of creation plan. It would be a proper prediction if Archeopteryx had one or some important details not present in known living animals. What are those details? How can it be called transitional or a missing link? Are its feathers somewhat finny or are they as good as in modern birds (looks like as good as)? No living bird has claws in wings (some do)? Something about the structure of its bones? Something else?
In comparison, Mendeleev drew up the table of the elements and identified some holes in the table. His prediction involved simply describing what would fit a particular hole. Later that element was isolated. That’s how it was a successful prediction.
Darwin’s finding is not quite comparable, but let’s say it’s acceptable. However, it follows from the general classifiability of animals in higher and lower hierarchies. The classifiability by itself does not prove that things evolve. It only proves that we tend to find gradual hierarchical harmony and order in nature. Rather trivial. Just like chemical elements can be nicely arranged and classified, but they don’t evolve by themselves into other elements. They have to be subjected to certain conditions and environments, then they do.
Erik,
Evidence such as the invariance of 55/64 positions in the genetic code (with a clear rule governing the exceptions), common metabolism, substantial sequence identity in certain core genes across life.
Now you will say ‘doesn’t necessarily mean …’, and you would be right; it never necessarily means what it points towards. But it is entirely consistent with 1, whereas only consistent with more than 1 in certain scenarios, where the commonality arises from decision or constraint rather than descent. There is no apparent constraint, leaving Decision. One might imagine, for example, a Creator who separately devised Archaea and Bacteria using His standard ribosomal system. But there is nothing to distinguish that from Descent. If that’s what He did, it still generates evidence that points to 1 tree more strongly than several.
This denial of statistics is a great way to deny most of science. There is no actual link between smoking and cancer. No clinical trial of any drug ever identified an actual effect. Diseases cannot be traced back to their origin by phylogenetic means. Because, y’know, it’s not proof.
There is no such creation plan or ID theory, which predicts nested hierarchies. That’s just an unfalsifiable ad-hoc rationalization. There is no conceivable observation you could make, that could not be “accounted for” in the same way, retroactively, by positing that what we observe is what the designer wanted.
Yes, that’s how I intend to come across. I have written quite a large post on this before, which I will now copy-paste here:
Oh for fucks sake not that whole common descent vs common design tripe again. I think I’m just going to re-post this every time I see that crap.
On intelligent design you expect NOTHING IN PARTICULAR. All patterns are possible, but no pattern is any more expected than another unless you already know something about what goes on in the mind of the designer(do ID proponents happen to know that their intelligent designer WANTS to design nesting hierarchies? No they don’t, it’s just an ad-hoc rationalization).
All patterns are after-the-fact compatible with design, but none of them are exclusively or statistically predicted to appear over others when the designer and it’s methods are unknown.
Yes, design CAN explain all the same observations as evolution by common descent. But only in an empty and ad-hoc fashion that lacks explanatory power. (As in, it doesn’t actually explain or predict why we see what we see).“That’s just the way the creative designer wanted to make it”. There is no WHY or HOW in the design-rationalization. It is nothing BUT a rationalization come up with after the fact of discovery of nesting patterns of similarities.
Further more, why do human beings (the only intelligent designer we know of empirically) use “common design”? Mostly to save time and resources. Human beings copy previous designs because it is simply faster to do so when they need to make something that works. Nuts and bolts are reused because they work fine as they are, no need to change them. They are standardized, the factory has no good reason to invent new, sliiiiightly different ones every time (the same way we see, for example, regulatory regions mutate over time and phylogenies being constructible therefrom). Wheels are good for vehicles, easy to copy the basic pattern and save time, instead of having to re-invent a new method of locomotion every time. And build an entirely new factory to produce them.
But, life wasn’t designed by humans, so we can’t use analogies to anthropomorphic tendencies with respect to design. The kind of designer most ID proponents think designed life is an omnipotent supernatural designer, unconstrained by a faulty or mediocre imagination, unconstrained by a lack of time, unconstrained by resources, unconstrained by materials or anything at all. Such a designer would have absolutely no practical reasons for copying it’s designs over and over again in a derivative fashion by re-using and slightly altering items and structures from previous designs, to include in new organism that appear as evolved derivations of previous ones. None of the inferences we use to infer human design took place, are valid inferences for an unconstrained, omnipotent divine designer who does not have human concerns of practicality such as resources, lack of intelligence, imagination, creativity and time.
So there is a colossal ambivalence at the heart of the main ID proponents, who start with a conclusion that a specific and supernatural designer did the designing. This leads them into problems very quickly, for among other reasons that the nature, capacities and intentions of their designer, they assert, is unknowable, infinite and mysterious, respectively.
But in science we work with what we got and from what we know:
Observed designers, observed natural processes, observed manufacturing processes leaving observational evidence behind. The mechanism is understood, it makes testable predictions. It fits into already well-established frameworks of science from other fields: Physics, chemistry etc.(And in the case of human designs, human psychology, human inventions and technology and human culture). We can then form hypotheses and look for the results of the mechanism and either confirm or falsify the hypothesis.
Now comes “ID”. Do it have a mechanism? Nope.
What did it make? Depending on who you ask, all living organisms as-is, or occasionally it just dropped in to magically instantiate specific mutations at various points in the history of life, or zap a flagellum into existence.
Does their designer leave a signature, product description or trademark behind?(Stainless Steel, Goodyear, Firelli, Made in Taiwan, Nike, Microsoft, Coca Cola, nVIDIA… ) Nope.
Does it use tools? Nope (or no idea, things magically appear with no process of fabrication and construction).
When did it operate? No idea, millions and billions of years ago and now it’s suddenly stopped entirely no new creations take place. No creation has ever been observed. No macro-creation, not even micro-creation. Simply put, we observe absolutely nothing at all that looks like it is being instantly created with divine magic.
Do they draw analogies to human manufacturing processes? Well, they sometimes say that the designer re-uses old designs. What reasons do they have to expect their designer to do this? Since they don’t know the designers mind or intentions (they keep saying this to secular audiences), then they must be getting their idea from having seen human beings design things.
Ok, let’s just run with that. Let’s try the “accepts common descent and some degree of evolution but occasionally dropping in to make specific mutations happen by screwing with atoms at the quantum-level” (theistic evolution ala Kenneth Miller’s ideas). What testable predictions does this make? It should look exactly like evolution happened.
Just like evolution could have created all of life through mutations, drift and selection, with all the minor quirks and oddities being the result of incomplete lineage sorting, convergent evolution, drift, horizontal gene transfer and so on,
all expected to happen but never statistically significantly deviate from the main pattern, so does theistic evolution become observationally indistinguishable from naturalistic evolution.
In other words, an unobserved designer operating in the deep geological past, on a global scale, who has the ability to make specific mutations happen inside living organisms, is in competition with the observed fact that evolution happens naturally:
A) Mutations observationally happen, and we have no good reason to think they wouldn’t in the past too.
B) Those mutations affect the morphology and the physiology of the host organisms, and we have no good reason to think they wouldn’t in the past too.
C) The phenotypical and morphological effects of those mutations affect the reproductive successs of the carrier organism, and we have no good reason to think it wouldn’t in the past too.
So simply put, drift and selection observationally happens, and we have no good reason to think it wouldn’t in the past too.
E) Environments observationally change, and we have good reason to think they did in the past too (all of geology and the Earth-sciences testify to this).
F) Horizontal gene transfer observationally happens, and we have no good reason to think it wouldn’t in the past too.
G) Incomplete lineage sorting observationally happens, and we have no good reason to think it wouldn’t in the past too.
H) Convergent evolution observationally happens, and we have no good reason to think it wouldn’t in the past too.
Which is the simplest, most parsimonious explanation of the observed shared derived characteristics in extant life, then? The observed one that doesn’t require us to erect uneconomical unobserved entities: Evolution.
Ok, fuck that then. Moving on to the “all life made as-is” (space-aliens with superduper technology-ID-creationism).
Well, we should expect to find similarities between some species(still re-using old designs).
Ok, we find that. But we have at least two hypotheses that predict this same feature, so can we distinguish between them? Well, evolution predicts congruent nesting hierarchies in morphology, anatomical features and genetics.
But designers have been known to design nested hierarchies too.
Sure, but again the reasoning is arrived at ad-hoc. Mere re-using of old designs should not in itself yield highly congruent multiple nesting hierarchies into which all of life fits to an extremely high degree of confidence.
No, but it still could have been designed.
Yes! But why would we believe it was beyond the mere possibility? What grounds are there to believe that this is what happened?What are the odds that, even if you as a “designer” sits down and thinks “I’m going to reuse some of my older designs”, inadvertently produces a nested hierarchy, into which every species on the planet fits, both genetically, morphologically (and chronologically in the fossil record)? And why would you do it deliberately? What are the odds that your designer sat down and designed this specific pattern?
Does the observed nested hierarchy even make sense with respect to known, human designers method of design and manufacture?
Let’s see:
A look into the mind of the designer of the nested hierarchy:
“Common design – common designer” (by deliberately forming sets within sets within sets).
Here’s a small insight into it’s train of thought (courteously trying to give ourselves reason to entertain the design hypothesis by drawing from the only intelligent designer we know of – Homo Sapiens):
Does this make sense to postulate? No, it doesn’t. No mentally healthy intelligent designer would operate like this and produce a nested hierarchy indistinguishable from the one produced by the evolutionary process.
I submit that if you can convince yourself that your designer operated like this, then you’re either insane, deluded or infinitely gullible. Regardless, it would be irrational to believe it.
Yup. Same with language reconstruction: Fully consistent with the assumption that it all started with a single language. However, equally consistent with multiple independent origination. Need more evidence to conclusively determine either way.
Even though statistics does show not causes, it can easily show correlation. I’m not denying statistics, just recognising what it’s good for and what it isn’t good for.
As in macroevolution? Beyond microevolution? Is an expert willing to define a line between the two and show that macro specifically has evidence going for it?
And, all along, universal common descent is a distinct issue. Chickens lay eggs, but it doesn’t follow that they came from a single chicken or a single egg.
I’m not postulating anything like that. I’m only reporting what Darwin was up against. The thing is, if (macro)evolution is not a tangible causal pattern, it’s as good as any other sufficiently detailed regular pattern, with causes unstated or whatever different causes surmised.