"X only gives birth to its kind" is an invalid argument against Evolution
Debate Rounds (5)
An ofted cited argument against evolution is constructed as follows:
"No matter how many times it is tried, a dog only gives birth to dogs. Kinds beget their own Kind"
There are variations including using the word "Fundamentally different type.." and others, but all boil down to this.
I will show that this argument is invalid for 3 reasons:
1.) It pre-supposed that evolution MUST allow dogs to give birth to not dogs. This is not true.
2.) As the term "Kind" is objectively undefined, it can mean whatever the arguer wants it to mean at any stage.
3.) In general, it misses the point of gradualistic change over time.
This debate will be about the above statement; but the specific debate conditions are as follows:
- I will justify the 3 statements made above, and I will have the burden of proof to demonstrate these statements are true.
- My opponent must show his statement is true by explaining how evolution implies why X should give birth to something that isn't X. Either directly, (IE: parent dog, child != dog) or indirectly (IE: Ancestor = Dog; distant descendant != dog)
- This debate is about the logical validity of this argument, NOT about evolution as a whole.
- If explicit definitions are provided by opponent which implicitly changes the nature of the proposed argument (EG: defining a "Kind" to mean a species that differs more than 90% in DNA base-pairs) real world examples can be cited that either invalidate the premise (IE: we have seen that) or invalidate the terminology (IE: by your definition a Dog is the same kind as a cat).
- Reliable sources from both sides are ONLY required if calling into question an opponents facts.
First round for acceptance only; and rebuttals only in the final round.
So lets start with initial statement:
"No matter how many times it is tried, a dog only gives birth to dogs. Kinds beget their own Kind"
While this statement is pretty simple, it is used in three seperate ways to argue against evolution. I plan to cover all three, and demonstrate how each of them fall foul to a particular logical fallacy as highlighted in my original three statements. As it is not often clarified by the person making the statement, most of what I present here is interpretation of what the person means, and is normally based only on my experience of arguing with creationists.
If there is a more appropriate interpretation that may opponent wishes to use, please feel free, and I will rebut that also.
X only gives birth to it's kind: For evolution to be true; an organism must be able to give birth or produce offspring that is not the same species.
This interpretation implies that because one species diverges into another, there must be some point where parent and child are different species.
This is the simplest interpretation to discount. Divergence of species is not at an invidual level. Each organism will produce offspring that are almost but not quite the same as the parent; over many generations these differences accumulate (this is effectively what evolution is). After a number of generations, an organism maybe very different from an ancestral form, yeilding a new species; but at no point through the chain is any organism a different species from the parent, as they differ only by a small amount.
This is an example of misunderstanding gradualism. Primarily down to the categorisation of life. The very term species doesn't work very well at the individual nature; the term itself applies to a collection of organisms that are all the same; but in a changing, evolving system where things can change; and that there is accumulated change over generations, it is not possible to apply the term species properly to individuals. However, this inability to categorise, is often used to imply some biological occurance that one creature has some major difference compared to it's parent.
As such, evolution does not need such an example to occur.
X only gives birth to it's kind: For evolution to be true, we should be able to see dogs turn into cows, or fish into men
This is the second interpretation. While this is a nice rhetorical argument it is a gain based on a complete misunderstanding of evolution.
A key evidence for evolution and universal common descent, is the existance of a nested heirarchy, where life fits neatly into a tree structure when organised by common traits. The importance of this tree is mainly down to it not being violated; there are no examples where there are common traits in one branch that occur in multiple other branches without sharing a common ancestor with that trait.
The reason for this, is that such traits and adaptations require the specific mutations (which occur by random chance), which are then selected for. Having the same trait in multiple branches would require such a trait to have evolved multiple times independantly which is massively unlikely. The same function can evolve as it has in terms of wings in bats and birds; but these traits are not the same.
What this means, is dogs can't turn into any other species that is in existance. Each other species has a specific set of traits that cannot evolve twice. We can make dogs that are more cow like, in the same way dolphins are mammals that are more fish like than others; but it is not possible for those same traits to evolve twice due to probability.
As such, expecting evolution to produce such a change misrepresents the theory. It pre-supposed that evolution MUST allow dogs to give birth to not dogs. This is not true.
X only gives birth to it's kind: We should be able to see fundamental differences occuring between descendants and ancestors
The final way the argument is presented (when interpreted liberally, and most scientifically), is that Evolution should be able to produce species with significant amounts of differences from an ancestor that amounts to some "fundamental" difference, or something that is now a different "Kind".
The first issue with this, is that species cannot out-breed their ancestry. No matter how many generations and species that were produced from the first Eukaryote; they are still eukaryote. No matter how many generations and species spawned from the ancestor or verterbrates, they are still verterbrates. Humans are still classified as therapsidia; because we are still therapsids because the diagnostic features of those species are passed down and shared with all ancestors.
In this way, no species will ever become fundamentally different from it's any of it's ancestors. A Dog will never produce a non-dog in the same way a mammal has never produced a non-mammal. This is evidenced in the nested heirarchy and the fossile record too; at no point did any species become different than it's ancestor: such an occurance would indeed invalidate evolution by producing a violation of the nested heirarchy.
The second issue comes when you take the argument even more liberally and assume that a "fundamental difference" is merely a number of additional traits.
This is where the argument becomes dishonest. Evolutionary biologists have seen innumerable different traits in multiple species evolve and accumulate. From dogs, to flies, to sticklebacks and many others. We have seen changes in organ structure, size, shape, bone formation, bone structure and a great number of other types of mutation that need to have occurred at some point to explain the biodiversity of life.
In this regard, seeing species differ by 1 trait, or 2 traits is not enough; with the lack of a definition of what "Fundamental difference" actually means, there is no way to objectively define when one species starts to become different from another. It is "intuitive" that Fish and humans are fundamentally different as they have a lot of different traits. However, it is not quite as intuitive when you start getting to more closely related species. For example the most amphibian like fish compared to the most fish like amphibian.
In this regard, this argument deliberately makes it unclear exactly how much change is "fundamental", or how much change is required to make a "new kind", meaning that whoever posts such a statement is free to reject any example of observed change as not meeting their criteria, as there is no definition of what that criteria actually is.
Before we begin, I will not be making any references to any religious text apart from the words of the topic at hand.
Also I will not be putting forward arguments for creationism as that is not the topic for debate. The only thing I will be addressing is the validity of the criticism at hand.
The Taxonomy classifications attributed to animals is only possible due to the extinction of all the myriad transitional species that have existed since the beginning of life. If these species still existed there would be an indefinable gradual difference between flora and fauna types. This would make it impossible for us to draw a line in the sand and delineate between their respective attributes. Taxonomy is totally reliant on evolutionary gaps for it to be a functional and workable classification system.
Prior to the biological classification system that we use now, humans used different names to define and classify groups of animals - In a biblical sense this word is "kind". Biologists when classifying life are sometimes grouped into lumpers and splitters - the former grouping animals into larger groups, the later attempt to define each variation to much greater detail. The word "kind" appears to be firmly in the lumping category. and for the sake of argument let us put forward that they relate to a group of animals that are able to interbreed with each other - i.e. kind comes from kind.
Although scientific taxonomy is much more granular and involves multiple layers of classifications, it doesn't preclude this system from having similar arbitrary lines drawn between different animals. This is apparent as "splitters" are always keen to claim the discovery of new animal types whereas lumpers will disagree. The problems of classification exist whatever name you allocate to an animal.
This is becoming increasingly an issue as DNA evidence moves animals around the tree of life as previously established observed traits and relationships are superseded by new DNA evidence - e.g. Falcons are now considered more closely related to Parrots than to Hawks and other birds of prey. (1)
When classifying animals, we do not look at a population " we look at individual examples and then compare these creatures with others of a similar biological structure. If they are suitably different, they may even get their own name " and finding a new individual specimen can be the highlight of a biologist"s career. Similarly with fossils " they are not classified in reference to a large population, they are classified based on a collection of fossilised remains of a single individual, or even sometimes only a small smattering of bones of a single individual.
It is worth noting that taxonomy did not begin by mapping out the tree of life in relation to evolution and common ancestors as some would lead you to believe, rather it was purely designed by grouping living things by their shared characteristics. Names that we use commonly today for classification, such as "vertebrates" and "invertebrates" were penned by Aristotle nearly 2500 years ago. (2)
As such, a dog will always be a vertebrate, not necessarily because he is descended from a vertebrate, but because he has vertebrae.
Evolutionary theory does not state that fish gave birth to frogs, rather each successive generation is slightly different to the one that came before, allowing a fish like creature to evolve into both populations of fish and amphibians. (With some allowance for a bit of status every now and then)
As such, over time, generations of a lineage would have to cross over the established arbitrary measures of how we define an organism/animal etc. Some biologists such as Richard Dawkins put forward that the first mammals were a shrew like creature. So this shrew (like creature) would have kept producing more shrews, but over millions of years they would cease falling into the shrew (like) category, and instead find themselves as primates, equines, or canines and the list goes on.
Classification during this process is like asking what gear you are in on a variable speed gearbox (found in scooters). It cannot be defined as the arbitrary demarcations we put between classifications begin to blur
So just like this shrew over time became the variety of mammals we see now, we would expect dogs to evolve in a similar manner so that over time they cease being what we define as "dogs" and become another species altogether over many many generations of mutation and natural selection.
But this is not what we observe in the natural realm. We have had several thousand years of intense selective breeding of dogs and they still remain dogs despite their huge variation from chihuahua to great danes... The same for cattle, horses, sheep and the like.
Alternatively, these potential new forms may still be known as "canine" but many successive layers of sub-classification would need to be added to the taxonomy so that it could then distinguish between all the variations of animals that no longer resemble what we would currently consider a "dog".
There could be "dogs" who evolve to:
Have opposing thumbs etc. etc.
Through convergent evolution, their characteristics would be visually more similar to other types of mammals (although their DNA would state otherwise). Evolutionary theory teaches us that certain traits have evolved multiple times along different branches of the tree of life. Once again we can refer to the recent reclassification of Falcons who obtained their similar traits to other birds of prey independently. (1)
There is no reason to think why this wouldn"t, or couldn"t happen again. Just as we are not considered a "shrew" as our distant ancestors were, a horned winged bipedal "dog" would no longer be considered what we classically consider a dog.
Through gradual changes over successive generations, a species, or "kind" should morph into another kind. As we have not seen this occur in existing animals over several millennia, it is a fair criticism of the evolutionary model. We see a relatively wide range of variation within a species - sometimes happening in only a few short generations - such as the Russian Domesticated Silver Fox experiment (3) - but there is an observable limit to this variation.
Direct observations should be taken with more weight than speculations on the existence of family trees that are having to unpredictably evolve themselves counter intuitively as we map the genome of different creatures.
It is completely scientifically valid to use a directly observable occurrence that has been witnessed over several millennia to challenge an ever changing inference.
Ramshutu forfeited this round.
"X only gives birth to its kind: For evolution to be true; an organism must be able to give birth or produce offspring that is not the same species."
As mentioned in my earlier round, the biological taxonomy is only able to be functional due to the gaps in between what we see in observable extinct and extant fauna. An animal is defined as a mammal as it feeds milk to its babies and are warm blooded. During the course of evolution there would have had to be a point at which a reptile stopped being cold blooded and started feeding milk to its offspring. These instances may not have happened at once either. We may have had warm blooded reptiles, or cold blooded mammals " neither of which we have classifications for as each description has not been observed and as a result is mutually exclusive and counter intuitive.
That being said, at some point there would have been at least one individual that would have had to cross over the arbitrary line in the sand that we have created in defining reptiles vs mammals. This individual then would have gain some traction and their population would have grown.
So out of all the attributes of a mammal, what is the ultimate defining characteristic? As birds are also warm blooded, feeding young milk would be the defining characteristic of a mammal. Along the evolutionary path there would have been a point at which this began " and it would have begun with one individual, and at that point that youngster would have been, not only another species but a totally different class.
I am surprised my opponent claims that evolution does not happen at the individual level when evolution can only occur with the mutations in individuals that become more frequent within a population due to natural selection.
This criticism of evolution is not a misunderstanding of gradualism, it simply highlights that if evolution is true, the current classification method that we use is quite deficient in being able to differentiate between gradually evolving populations. The arbitrary definitions that we assign to a specimen completely break down as soon as an individual specimen or a group of specimens cross over these arbitrary lines in the sand.
"X only gives birth to its kind: For evolution to be true, we should be able to see dogs turn into cows, or fish into men"
This is a bit of a simplification and misrepresentation of what evolutionary theory states, but there is a valid point in there amongst the mis-information.
We would not expect to see a dog turn into a cow or a fish into men " especially over one generation. But over many many generations a dog could evolve into a cow like creature just as a shrew like creature has evolved into the current mammalian menagerie that we currently have.
Over time according to evolutionary theory animals will continue to change and evolve into many weird and wonderful random combinations. As mentioned earlier, there are significant variations within dogs, yet they are still dogs. As soon as they are geographically and reproductively isolated we would expect they should change " but this hasn"t been observed yet.
. "The importance of this tree is mainly down to it not being violated; there are no examples where there are common traits in one branch that occur in multiple other branches without sharing a common ancestor with that trait".
This is quite a completely false statement. Similar traits can be found in multiple branches. Such instances are referred to as convergent evolution. Falcons and Hawks were thought to be closely related due to their similar bird of prey traits, but as referenced earlier Falcons are more closely related to Parrots.
The tree is often violated, but evolutionary theory has the flexibility to overcome these contradictions via convergence, or the ability to add additional branches that either continue on today or are dead ends with yet another unknown common ancestor being created.
"X only gives birth to its kind: We should be able to see fundamental differences occurring between descendants and ancestors"
We do see fundamental differences between descendants and ancestors. Dogs are not sea dwelling creatures, nor are they reptilian. They may share some similar traits, such as a backbone and the like, but dogs are warm blooded, have fur, not scales and don"t lay eggs. In many respects they are nothing like reptiles or their sea dwelling ancestors at all. These are fundamental differences that dogs have with their ancestors.
The beauty of evolutionary theory is that similarities are evidence of evolution, whilst differences are also evidence of evolution. Also if any new creature is found that doesn"t fit nicely into the tree of life, the solution is simple, another branch is added or a creature is moved from one branch to the next.
"The first issue with this, is that species cannot out-breed their ancestry. "
Dogs may not have out outgrown their invertebrate-ness, but they certainly outgrew their fishiness and their cold-bloodedness
"In this way, no species will ever become fundamentally different from it's any of its ancestors. A Dog will never produce a non-dog in the same way a mammal has never produced a non-mammal."
But reptiles have evolved into mammals, dinosaurs into birds, these are fundamentally different types of animals " all species are all fundamentally different from their ancestors.
Evolutionary theory is powerful, it shows how one type of creature can diverge and become many thousands of kinds throughout the world. Is it too much to ask to observe this occurring? If we don"t see it occur it is definitely a valid criticism of the theory.
Ramshutu forfeited this round.
Ramshutu forfeited this round.
In summary, "X only gives birth to it kind" is a valid argument against evolution as it is what we have observed for several thousand years and should be taken with as much weight than inferred past occurrences that have not been witnessed and cannot be tested or replicated.
Vote Con because even when I am stood up three times, I still keep my sense of humour.
1 votes has been placed for this debate.
Vote Placed by lannan13 2 years ago
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