Tree of Life: What Creature Was at the Fork?

[Papias]

OK, let me try to clarify things here.

You are using two different and incompatible definitions of "human" here.

They are:

Human1:

rush wrote: Humans can't reproduce with non-humans (at least as far as we can tell amongst the current living creatures).

(In other words, "Human" is defined as not being able to reproduce with things that don't look like modern humans. To say "non-humans" is to create a circular definition. A circular definition says nothing, such as "squares are things that are square.", or "A micyescethys is somethat that has the properties of a micyescethys .")

Human2:

rush wrote: Obviously, there had to be a first human.

(in other words, "Human" is defined as the first to cross some line, which you will not give - because as shown, the "conception" line is not a sharp line.)

*******************************
Now, look back at how you have switched back and forth between these. Take your statement:

Humans can't reproduce with non-humans (at least as far as we can tell amongst the current living creatures).

If using definition #1, then this is true, because it simply repeats the circular definition.

However, using definition #2, then that same statement is clearly false - the first "human" over some imaginary line would of course be able to reproduce with it's opposite sex parent, they are practically identical.


What as transpired so far on this thread has been a textbook case of the fallacy of equivocation, the switching back and forth between two definitions. That's why we've answered "yes" and "no" - because those are alternately correct depending on which of your definitions we are trying to use.

Up to now, I hope this equivocation has been accidental. However, equivocation is often used dishonestly, just like quotemining, appeals to popularity, false authority, and many other fallacies. I hope you will stop equivocating.

At the start of this thread, your "forks" request seemed like a fair question, and answers (including an example on forks) were given. After that, Kaylie especially, as well as others, expended a lot of effort to help you on this point. Thanks to all of them for their knowledge!

In Christ-

Papias

 

[rush1169]

Nm

 

[rush1169]

Thank you for post. I certainly had no idea I was committing a fallacy of equivocation. Heck, I didn't even realize that

rush wrote: Humans can't reproduce with non-humans (at least as far as we can tell amongst the current living creatures).
and
rush wrote: Obviously, there had to be a first human.
were being interpreted as me making up two definitions of the word human.

I thought "Humans can't reproduce with non-humans" was just a fact that we all know and I thought "There had to be a first human" just made sense since there was once zero humans and now there are more than zero humans. One or both of those are apparently wrong. I'll leave it at that.

OK, let me try to clarify things here.

You are using two different and incompatible definitions of "human" here.

They are:

Human1:

rush wrote: Humans can't reproduce with non-humans (at least as far as we can tell amongst the current living creatures).

(In other words, "Human" is defined as not being able to reproduce with things that don't look like modern humans. To say "non-humans" is to create a circular definition. A circular definition says nothing, such as "squares are things that are square.", or "A micyescethys is somethat that has the properties of a micyescethys .")

Human2:

rush wrote: Obviously, there had to be a first human.

(in other words, "Human" is defined as the first to cross some line, which you will not give - because as shown, the "conception" line is not a sharp line.)

*******************************
Now, look back at how you have switched back and forth between these. Take your statement:


If using definition #1, then this is true, because it simply repeats the circular definition.

However, using definition #2, then that same statement is clearly false - the first "human" over some imaginary line would of course be able to reproduce with it's opposite sex parent, they are practically identical.


What as transpired so far on this thread has been a textbook case of the fallacy of equivocation, the switching back and forth between two definitions. That's why we've answered "yes" and "no" - because those are alternately correct depending on which of your definitions we are trying to use.

Up to now, I hope this equivocation has been accidental. However, equivocation is often used dishonestly, just like quotemining, appeals to popularity, false authority, and many other fallacies. I hope you will stop equivocating.

At the start of this thread, your "forks" request seemed like a fair question, and answers (including an example on forks) were given. After that, Kaylie especially, as well as others, expended a lot of effort to help you on this point. Thanks to all of them for their knowledge!

In Christ-

Papias

 

[Kylie]

I said there were once zero humans and later there were lots of humans, so there must have been a first human born of a non-human. You say 'no' because 'each new generation in the population became more and more human-like until the entire population was human.' A 'population' is a homogenous group label used to let the listener know that the speaker is referring to all the individuals. A 'generation' is a homogenous group label used to let the listener know that the speaker is referring to a subset of the population of individuals. Populations and generations don't engage in procreation. Therefore, you must mean when you said 'each new generation in the population became more and more human-like until the entire population was human' that each new group of individuals born became more and more human-like until finally a new group of individuals born were human and, after all the current living prior generations died the entire population of individuals were human. In other words, a group of non-humans birthed a group of humans.

No. What I am saying is that if you look at how the individuals in a population changed over time, they became gradually more and more human. There was never a point where a non-human gave birth to a human. Remember my square analogy? The squares start of blue and turn to red. But there is never a point where there is a Red square next to a non-red square.

I understand what you are saying and the gradual, divergent evolution analogy keeps coming up so I need to add this:

Sexual compatibility is all or nothing. By 'sexual compatibility' I'm referring to procreation such that the offspring is a 100% viable, healthy, and fertile individual. Not kinda viable, kinda healthy, or kinda fertile. All or nothing. Gradualism cannot exist at conception. Whatever is going to be born as a result of the conception is a product of an individual male and female. Neither the population nor the generation are making a baby and the couple engaged in the act aren't gradually mixing genes of generations or populations.

Now, when I ask "Was there ever a first sexually-compatible-with-modern-humans human born?", if one is going to explain why the answer is 'no' they should not include references to populations, generations, or the idea of gradualism. Populations, generations, and gradual change do not have sex and gradually make babies

It's more the probability of producing a viable offspring. I could go back in time 200,000 years and reproduce with a male living back then, and my chances of getting pregnant from him wouldn't be as good as they would be if I tried the same thing with my husband. If I was travel back in time even further, then my chances of getting pregnant would drop more and more.

It's like if you try tossing a scrap of paper into the bin. If you are close, you might get 100% accuracy. But if you move further away, you might still get it in, but sometimes you'll miss. Again, this is an all or nothing scenario - you're either going to get the paper in the bin or not. But you can't say that there's a point where you'll get it in 100% of the time and then it immediately drops down to 0%.

 

[Kylie]

Thank you for post. I certainly had no idea I was committing a fallacy of equivocation. Heck, I didn't even realize that

rush wrote: Humans can't reproduce with non-humans (at least as far as we can tell amongst the current living creatures).
and
rush wrote: Obviously, there had to be a first human.
were being interpreted as me making up two definitions of the word human.

I thought "Humans can't reproduce with non-humans" was just a fact that we all know and I thought "There had to be a first human" just made sense since there was once zero humans and now there are more than zero humans. One or both of those are apparently wrong. I'll leave it at that.

There was a population of non-humans. If you could go back in time and watch them, you;d say, "Those are not Humans." But then if you could speed up time and watch as the group evolves over generations, you'd see them develop to be more and more human like until they were humans.

 

[mzungu]

This may sound unethical but if a chimpanzee were to be impregnated with human sperm there is a probability of a foetus developing up to a stage. If we were to impregnate a human with a fertilised Chimpanzee egg then the chances are that the human may accept the egg and become a surrogate mother. We don't know simply because such experiments are unlawful. To what stage the fertilization will reach depends on how close genetically we are to chimpanzees or bonobos. Just a thought. Perhaps one of our resident biologists could shed some light here?

 

[Kylie]

This may sound unethical but if a chimpanzee were to be impregnated with human sperm there is a probability of a foetus developing up to a stage. If we were to impregnate a human with a fertilised Chimpanzee egg then the chances are that the human may accept the egg and become a surrogate mother. We don't know simply because such experiments are unlawful. To what stage the fertilization will reach depends on how close genetically we are to chimpanzees or bonobos. Just a thought. Perhaps one of our resident biologists could shed some light here?

I gotta disagree, at least about the fertalisation of the egg, due to the fact that humans and chimps have a different number of chromosomes.

 

[mzungu]

I gotta disagree, at least about the fertalisation of the egg, due to the fact that humans and chimps have a different number of chromosomes.

Ah yes that one slipped by me. But if a fertilised egg (chimpanzee sperm and egg)were implanted into a surrogate human? Will the surrogate mother reject the fertilised egg?

 

[rush1169]

I gotta disagree, at least about the fertalisation of the egg, due to the fact that humans and chimps have a different number of chromosomes.

I thought chromosome count is not relevant in reproduction?

 

[Papias]

rush wrote:

Thank you for post. I certainly had no idea I was committing a fallacy of equivocation. Heck, I didn't even realize that...

No Problem. I'm glad that we could work that out. Too often I see people guess that the other is being dishonest, especially after how these discussions can go sometimes.

Originally Posted by Kaylie

I gotta disagree, at least about the fertalisation of the egg, due to the fact that humans and chimps have a different number of chromosomes.

I thought chromosome count is not relevant in reproduction?

rush is right, it's not necessarily a barrier. For instance, it's well known that horses often have different numbers of chromosomes, and can reproduce, etc. It can be a barrier, but doesn't have to be a barrier if there is enough overall similarity.

Papias

 

[Loudmouth]

rush is right, it's not necessarily a barrier. For instance, it's well known that horses often have different numbers of chromosomes, and can reproduce, etc. It can be a barrier, but doesn't have to be a barrier if there is enough overall similarity.

Papias

Przewalski's horse has a different chromosome count than the domestic horse, but they are able to produce fertile hybrids.

There are even humans with different chromosome counts that are able to have normal children.

The 44 Chromosome Man | Understanding Genetics

 

[Kylie]

Here's a little diagram I made showing the evolution of humans, chimps and bonobos.

In this diagram, the bottom is far in the past and the top is the modern day. The most recent common ancestor of all humans, chimps and bonobos is at the bottom, coloured purple and labelled. This is a single population of ancestral animals. They weren't chimps (which are red), they weren't bonobos (which are blue) and they weren't humans (which are green).

For whatever reason, this population was split. One side of the split evolved into humans (we can see this on the right side of the diagram). Notice that there is a gradual change from purple to green. There's no point where there's purple next to green. The colour just gradually becomes less and less purple and more and more green. In the same way, these animals would have become less and less ancestor like and more and more human like.

On the other side, we can see the evolution of the bonobos and the chimps. For a long time after the split with the human/chimp/bonobo common ancestor (the purple animals at the bottom), they were on the same line, and there were no separate chimps and bonobos. But once again, there was something that split them into two different populations. So the chimp bonobo ancestors evolved from the purple animals to the yellow animals before there was some event that split them.

In this case, we have a fair idea what this event was. If we look at the habitat that chimps and bonobos live in, we can see that the Congo River goes straight through the middle. We find bonobos on the south side of the river and chimps on the north side. Because neither species can swim well, the river is a barrier that they cannot cross. So, the chimp/bonobo common ancestor (in yellow) was split into two different populations by the formation of the Congo River about one and a half to two million years ago.

And from this split population, the chimps and bonobos each evolved separately, the chimps becoming the red animals and the bonobos becoming blue. Again, you can see that the change is gradual over a long time. There's no point where a non-bonobo gives birth to a bonobo.

 

[rush1169]

@KTS - Thank you for the graphical presentation, but I still can't understand how it escapes this problem:

1) Human population was zero.
2) Humans birth one at a time.
3) Human population is > zero.
4) A pair of non-humans cannot birth a human.

There are all facts as far as we can tell. However, for humans to exist, at least one statement must be false. If #1 is false, then humans have existed as long as the universe has existed, or at least earth. #2 cannot be false due to observation. #3 cannot be false due to observation. If #4 is false, then a pair of non-humans can birth a human.

So, between #1 (human population was zero) and #4 (non-humans cannot birth humans), I have to decide which of the two is most likely to be false based on all the collective human knowledge of everything. I've not been around long enough to observe either, so I can only guess the most likely false statement.

My guess is that #4 is the most likely false statement between those two. What is your guess?

 

[Ursus scientia]

@KTS - Thank you for the graphical presentation, but I still can't understand how it escapes this problem:

1) Human population was zero.
2) Humans birth one at a time.
3) Human population is > zero.
4) A pair of non-humans cannot birth a human.

There are all facts as far as we can tell. However, for humans to exist, at least one statement must be false. If #1 is false, then humans have existed as long as the universe has existed, or at least earth. #2 cannot be false due to observation. #3 cannot be false due to observation. If #4 is false, then a pair of non-humans can birth a human.

According to ToE life evolves. So humans don't suddenly pop into existence from a zero population, they develop along the line in KTS's (rather visually pleasing) graphic. Every animal on the right-hand branch from the MRCA between humans and chips lives, reproduces and dies. The changes over generations accumulate and result in what we are now: modern humans.

The same is true for chimps and bonobos, their populations emerged from a population of similar but slightly different animals, which emerged from an earlier population of similar but even more different animals, etc. etc.

So #1 is false.

 

[Kylie]

@KTS - Thank you for the graphical presentation, but I still can't understand how it escapes this problem:

1) Human population was zero.
2) Humans birth one at a time.
3) Human population is > zero.
4) A pair of non-humans cannot birth a human.

There are all facts as far as we can tell. However, for humans to exist, at least one statement must be false. If #1 is false, then humans have existed as long as the universe has existed, or at least earth. #2 cannot be false due to observation. #3 cannot be false due to observation. If #4 is false, then a pair of non-humans can birth a human.

So, between #1 (human population was zero) and #4 (non-humans cannot birth humans), I have to decide which of the two is most likely to be false based on all the collective human knowledge of everything. I've not been around long enough to observe either, so I can only guess the most likely false statement.

My guess is that #4 is the most likely false statement between those two. What is your guess?

Here's the problem. Look at the human side of the graphic. It goes from purple to green. you are saying, basically:

1) Green population was zero.
2) Greens birth one at a time.
3) Green population is > zero.
4) A purple cannot birth a green.

As you can see, purple never births green. It just becomes more and more green and less and less purple.

Imagine you could travel back in time to when the human ancestor was around, the purple in my diagram. Also imagine that you could live long enough to make it to the present day.

You would see the ancestor, and you would be able to tell it wasn't human. As time went on, you'd see more and more generations passing. Each generation would be the tiniest bit more human that the previous one (just like each "generation" in my diagram is a little bit greener than the previous one). These differences would be too small for you to notice over just one generation. But over many generations, you'd say something like, "I can see that the braincase is becoming more human in size." This would happen with other features. But you'd probably just consider it to be an ancestor with a slightly more human braincase. Over many generations, all these little changes would add together, and they would render the population more and more human. Eventually they would be human.

You have to stop thinking in terms of "Human" and "Not Human." There's no boundary point. There's no point where it goes from being not human to being human. It gradually happens over many generations. It's a gradual change, not an instant one.

 

[rush1169]

Here's the problem. Look at the human side of the graphic. It goes from purple to green. you are saying, basically:

1) Green population was zero.
2) Greens birth one at a time.
3) Green population is > zero.
4) A purple cannot birth a green.

As you can see, purple never births green. It just becomes more and more green and less and less purple.

Actually #4 should read:
4) A non-green cannot birth a green.

However, even in your graphic, there is a point where a green immediately follows a non-green.

I haven't quoted the rest of your post because it followed a false assumption (that a purple immediately preceded a green).

 

[Subduction Zone]

Actually #4 should read:
4) A non-green cannot birth a green.

However, even in your graphic, there is a point where a green immediately follows a non-green.

I haven't quoted the rest of your post because it followed a false assumption (that a purple immediately preceded a green).

No, there is a gradation from purple to green. If you were observing the change occur there would be no point where you looked at one generation and said it was non-green and then look at the next generation and declare it to be a green.

It is similar to looking at a series of pictures taken one a day of a person's life. There is no one point when you would say "this day it is a baby, and here on the next day it is not" or "here the child is an adolescent this day and the next day he is no longer an adolescent". The change is continual, gradual, and imperceptible.

ETA: And you are wrong, KTS was right, a purple cannot give birth to a green.

A purple can give birth to an almost purple. And so on etc until we get an almost all green can give birth to a green.

 

[Kylie]

You're not quite there. If you take any green pixel in my graphic and go to the pixel immediately underneath it, you will find it is a colour that is still what you would call green. Not quite as green, perhaps, but still green nonetheless.

 

[Subduction Zone]

You're not quite there. If you take any green pixel in my graphic and go to the pixel immediately underneath it, you will find it is a colour that is still what you would call green. Not quite as green, perhaps, but still green nonetheless.

Correction noted. I was going to get picky about pixels but found out that they are the minimum group that defines a color. Rats!

 

[Ursus scientia]

Correction noted. I was going to get picky about pixels but found out that they are the minimum group that defines a color. Rats!

This is why it's all about vector graphics. Though pixels are a better analogy. : P