No. The theory of evolution does not logically follow from the examination of the evidence. Unlike the example you gave of footprints in the mud,the evidence used for evolution theory - common structural and genetic traits and similar patterns of traits - does not logically point to common ancestry if there is no way to show reproductive links between species.
You are trying to work the logic backwards. Footprints in the mud are evidence of where the burglar broke into the house. Common structural and genetic traits are evidence of reproductive links. You don't have to prove reproductive links first and then look for commonalities. You use commonalities, and differences as well, to work out what the reproductive links had to be.
It is reproductive lines that matter in regard to ancestry and descent. That is what is meant by ancestry and descent.
No disagreement there.
Neither logic nor biology determines that the variety of species must have descended from one common ancestor or that many species with many traits in common could not have come into being separately.
Given the evidence we now have, both morphologically from living and fossil species and genetically, as well as through patterns of geographical distribution, past and present, and physiology and biochemistry, common descent is the only theory that accounts for all the evidence.
But evolutionists want to connect everything with everything else according to "patterns" of commonalities and similarities,so that nature appears infinitely self-creative and malleable.
Well, what's wrong with that? Wouldn't that be a wonderful testimony to the infinitely creative mind of God? (Or do you assume that where "nature" is, God is not?)
I don't call the workings of nature "mechanisms".
I don't particularly like that term either. I only used it because you did.
I prefer to think along the lines of processes in nature.
There are not many things in nature that can rightly be called mechanical,except bone structures and digestive systems. God does and sustain the workings of nature,and it is good to acquire knowledge of them,but the naturalism and mechanism of scientists leads them to misinterpret natural causation where the cause of effects is beyond detection,so that they attribute powers to nature or even to nothing that cannot exist.
I don't think you can put all scientists in one basket psycologically or philosophically. If they interpret "natural causation" as excluding Gods providential sustenance of nature's workings, I would agree that is a misinterpretation. But some do and some don't.
And every single creature is itself a species in the original sense of form or kind.
In the original sense? Are you going back to the Aristotelian sense? I know that up until Linneaus published his Systema Natura, it was common to use only two levels of classification: genus to refer to a collective, and species to refer to an individual member of the collective. So one might refer to "tree" as a genus and "elm tree" as a species. Of course since "elm tree" is a designation that itself refers to a plurality of trees, one can also treat "elm tree" as a genus and "slippery elm" as a species. And since this is still a collective (within the larger collectives of "elm tree" and "tree") we can continue to carry the process toward the individual until we get to "the slippery elm tree in my backyard" which is an individual and can be divided no further.
Is this what you mean when you say "every single creature is itself a species"? Like, my daughter's pet beagle is itself a species? But it is also one of the whole breed of dog called beagles, and beagles are one breed of the animal we call dogs, and dogs are part of a larger family we call wolves, etc.
What Linnaeus did was fix the term "species" to the smallest collective distinguishable from other collectives and "genus" to a grouping of "species". Then he invented new names for larger collections up to "kingdom" for all animals and for all plants. And despite some major revisions in the system, it is still the case in scientific discourse that "species" is not used of an individual creature.
Common descent was assumed by scientists from Linnaeus' taxonomy,which lumps together different species based on similar traits,even before Darwin developed his theory of natural selection.
Not assumed. Deduced. And deducing something logically from the taxonomy is coming to a conclusion, not making an a priori assumption. In a sense natural selection in itself is not related to common descent. But it does depend on "descent with modification" ( a term Darwin liked to use) and so it also leads to the conclusion of common descent. The very fact that you speak of this concept being derived "
from Linnaeus taxonomy" shows the thought process goes toward common descent as a conclusion from the evidence; it is not an a priori assumption used to organize the evidence.
Common descent doesn't give a reasonable explanation for that.
Sure it does. The explanation is that these are features inherited from the ancestor of the group.
That is a question of why some things exist and others don't,which goes back to the will and creative action of God.
And that is not an explanation. We have no idea why God did not choose to create a vertebrate with six limbs. Or to vary the number of cervical vertebrae in proportion with length of neck. These things are certainly possible with direct creation that is not dependent on inheritance. But since God provided for inheritance, we can discern patterns in inheritance that make sense of these things.
Evolutionists focus on natural selection,genetic reproduction and allele frequencies,not reproduction. When they talk about reproduction,they portray it as a mechanism of evolution,not as the very means of descent and inheritance,or descent and inheritance itself. If scientists focused on reproduction and all that it entails for the study of the origins of species,the theory of evolution would have to be converted into a theory of creation.
I think you are short-changing the scientists. Inheritance and reproduction are at the heart of evolutionary theory.
Scientists do ignore it in regard to the origination of species. They ignore the fact that species consist of individual creatures that begin to exist through reproduction,and they instead focus on gradual,non-creative processes to explain how species originate.
In scientific terminology, a species is not an individual creature like my daughter's pet beagle. It is the reproducing group that this individual is part of (in this case, domestic dogs). So, it is not that they are ignoring individual creatures, but that they are using "species" with a definition common to biological science. You are not going to change that. So you will need to rephrase your objection in a way that it can be expressed in scientific terms.
Scientists look for both. What is taken as supporting evidence is sometimes so convincing that it is taken for proof,sometimes rightly,sometimes wrongly.
That is true. Any scientist will tell you that technically, all scientific conclusions are tentative, held provisionally to be true until there is solid evidence to the contrary. But, as Stephen J. Gould once pointed out, sometimes the evidence is so convincing that it is perverse to withhold such provisional consent. And it is not unknown for scientists in such cases to speak of the so-called provisional truth as proven fact. Nevertheless, scientists do know that the knowledge they discover is not based on the pristine logic of a syllogism, but on evidence which is always partial and open to revision.
What sort of fossil evidence do you mean,and how would it help to determine if two species were reproductively compatible? Even if a group of species is discovered which appear to form a transitional taxonomic pattern,this would not demonstrate reproductive relatedness,and it is only plausible if reproductive compatibility between the species is assumed. But that is just what needs to be known and cannot be known. If you can demonstrate reproductive compatibility between species,you have already proven that they have a common ancestry.
As I said above, the logic of using evidence is not the logic of a syllogism. As you are no doubt aware, a syllogism is a form of reasoning in which, if the major and minor premises are both true, the conclusion deduced from them must also be true. And the classic form is something like this:
A. All men are mortal (major premise)
B. Socrates is a man (minor premise)
C. Therefore Socrates is mortal.
Now there is another kind of logic that does not lead to this kind of certainty.
We can illustrate it like this.
Given that all men are mortal, if Socrates is a man, he must be mortal.
We can show that Socrates is mortal.
Have we then shown that Socrates is a man?
No, we have not, for while it is true that all men are mortal, it is also true that all cats are mortal, so it is possible that Socrates is a cat rather than a man.
On the other hand, have we ruled out that Socrates is a man? No, it is still possible that Socrates is a man.
However, if we found evidence that Socrates is not mortal, then we have grounds for saying Socrates is neither a man nor a cat. This would falsify the original proposition "if Socrates is a man".
Science works more toward falsification than to proof, because it is often not possible to completely prove a hypothesis, but it is possible to falsify it. In the illustration above, we could not prove from his mortality whether Socrates was a man or a cat; but had we been able to prove his immortality we would falsify both his possible humanity and his possible felinity.
So the basic scientific proposition in seeking support for a hypothesis is to state it in an "if--then" framework.
"If Socrates is a man, then he must be mortal". Then we try to find out if he is mortal. If we do, we haven't proved he is a man, but we have proved that he could be. It would take additional evidence to narrow down whether he is a man or a cat or something else.
So the aim when working with fossils is not to show there is a reproductive link, but to ask "If there is a reproductive link" what logically follows as a consequence? Then the exploration begins to verify the existence of the logical consequence. The more logical consequences you can think of, and the more you can verify, the more plausible it becomes to say that there probably was a reproductive link.
So let's take a concrete example. It was first suggested nearly 100 years ago, that whales descended from terrestrial mammals of the arteriodactyl class (deer, cattle, sheep, etc.) Now, on the face of things, that sounds pretty far-fetched and there was very little evidence in its favour when the idea was first set out. However, beginning in the 1980s and on through the1990s a whole series of fossils were found that made it plausible. (And additionally, genetic evidence as well.)
Consider the changes that would have to take place for a terrestrial mammal to become a whale. Whales have a particular jaw and ear structure. They have no hind legs and they have flippers in place of forelegs. They have no nostrils, certainly not at the front of their snout. But they have a blowhole on top of their head. And these are just a few obvious morphological differences; there are many others. But if there is a reproductive link between a terrestrial creature and modern whales, what sort of evidence of that link would you expect to find in fossils that are part of that link?
Perhaps a terrestrial mammal with whale-like ear structure? (Pakicetus)
Perhaps a semi-aquatic mammal with a whale-like head and four swimming legs? (Ambulocetus)
Perhaps a swimming mammal with nostrils place midway up its face? (Aetiocetus)
Perhaps a whale with vestigial hind legs? (Basilosaurus)
As you see, many of the things we would expect from a reproductive link have actually been found--and again this is only a small sampling.
So we can say certainly that a reproductive link between a land-dwelling animal like Pakicetus and a modern whale is plausible. And the more such evidence we find, the more probable it is that the reproductive link is real.
We can also say it is plausible and probable because we have no other solid explanation for why these forms existed in the chronological order that they did.
So it is fair to ask, if a reproductive link is not the explanation of these forms, what is?
Can you prove that? I used to get into debates with scientists on the TalkOrigins forum and they were not able to refute my objections.
I can only go by what I see here. What I see here includes a non-standard definition of species. Possibly lack of acquaintance with the logic of science when evaluating evidence and a slightly outdated concept of evolution.
The theory holds that the variety of species developed over billions of years from a common ancestor through the processes of natural selection and genetic mutation. Natural selection led to the elimination of traits that were not helpful to survival and to the preservation of traits that were,while the gradual accumulation of genetic mutations led to the appearance of new physical characteristics and to increasing divergence in populations. Changes in allele frequency in populations led to the development of distinct species.
This is good. Much better quality than I usually see when I present this challenge. You have avoided practically all the usual gobbledygook. The last half is a bit weak, and to rectify it, you would need to understand (properly) what Eldredge and Gould were getting at with "punctuated equilbrium". Gradual accumulation of genetic mutations does lead to the appearance of new physical characteristics, but not necessarily to divergence. Divergence in populations requires separation, isolation of one part of the population from another which leads to a restriction of genetic sharing between the two groups. It is only in the context of closing off genetic sharing that the two groups can accumulate a different set of mutations, and so become differentiated into different species. So changes in allele frequency is only part of the explanation leading to distinct species. One needs these changes to occur in a scenario of isolated populations.
