John Harshman wrote:

eyelessgame wrote:

Jim Spaza wrote:

I accept the same scientific discoveries that atheistic scientists
accept. It is some of the conclusions that I do not accept. For
example, the discovery of fossils and analysis of DNA are not in
dispute. The dispute arises in the conclusion that all life must have
arisen through slow speciation coming from a single common ancestor
(atheistic) versus much life evolved to a certain extent from multiple
common ancestors (my view).

Can you put some meat on that bone? Give, say, three examples of your
"multiple common ancestors". Give a part of the tree of living
relationships that you believe has a common ancestor, and some "close"
apparent relatives that aren't related. Like for example, if you
believe all canines have one single common ancestor, say so -- say
"dogs, wolves, coyotes, and foxes have a common ancestor separate from
bears or cats", for example. Then we'll discuss the evidence that
leads to your conclusion, and contrast it with the evidence for common
ancestry.

A more apposite example -- because it's of crucial importance to the
creationists -- might be the same question but including Homo sapiens.
What species is it related to? What is the closest presumed relative (in
the standard view) that isn't actually related to it?

Yah, that's the obvious thing to bring up, but I already knew what he'd
say, and I even knew what he'd give as evidence -- he'd say man does
not have any nonhuman relatives, because Adam was formed from the dust
of the Earth by God, and Eve from his rib. I wanted to wait before we
tried to scale that wall.

I wanted to get him thinking about the whole continuum and *not*
specifically about humans, at first. Bring up the whole Carnivora set,
with felines and canines and hyenas and ursines, and have him decide
what in that area is and isn't related, and discuss what sort of
evidence would lead him to believe they are *all* related. And only
then take a step over to primates.

And once we talk about primates, I'd rather come at it from the Pan
side of the family. Chimpanzees are genetically closer to humans than
to gorillas, after all. If he's prepared to suggest chimps and gorillas
have a common ancestor but it's an ancestor not shared by humans, I'm
hoping we can start asking about the specific traits shared by
humans/chimps that gorillas don't share. Like (for example) hand
shape, or nonfunctional DNA sequences in common between humans and
chimps but not in common between chimps and gorillas. Why, I would
hope to ask, would that be?

Of course we also have the hominid fossil sequence, which is all
separate from the DNA evidence and all equally impossible for a
separate-creation person to explain. The problem I find with using
fossils in a discussion like this is that they don't *seem* so clear to
the layman, when one just looks at them and doesn't think hard about
the inferences. Jim has a layman's skepticism of fossils and what can
be confidently inferred from them. (I suddenly came to realize this
when I was discussing the Cambrian fossil set, earlier in this
thread...)

And again, is it something like 1000 common ancestors? How many
separate trees are you putting eucaryotes into? How about animals?
Multicelled animals? Chordates? Vertebrates? Mammals? Primates? Apes?

Where would you like to draw the line? Let's talk specifics. I'd love
to know where you think the lines might go. Feel free to be wrong --
just guess, and say you're guessing. Suggest something, anything,
without committing to it -- and you'll learn something from *why* your
particular choice was wrong.

(See, because if all life had a thousand common ancestors, each
different by an equal amount of DNA, vertebrates would still have a
single common ancestor. So I'm guessing you have some other idea about
how the line is drawn. What's your idea?)

What he said.

That's what I'm hoping to find out.

I'd be not terribly surprised if
it turns out that his "thousand ancestral species" turn out to be the
animals that he thinks were on the Ark. I'm hoping to get him to
realize that there is one whole *hell* of a lot of biology that isn't
vertebrate quadrupeds, and try to get him to think about just how
skewed layman perspective is on what constitutes the evolutionary
biosphere.

So far I have to say Jim's smart, honest, and curious, and can't
possibly stay misinformed if he keeps answering and asking and
thinking. I do hope, for his sake, that we lead him only to a greater
understanding of science, and not to a crisis of faith, because the
former is an awe-inspiring and wondrous thing, and the latter is an
unpleasant and often wildly depressing experience. And I find I like
him. :)

eyelessgame

Jim Spaza wrote:

eyelessgame wrote:

Jim Spaza wrote:

I accept the same scientific discoveries that atheistic scientists
accept. It is some of the conclusions that I do not accept. For
example, the discovery of fossils and analysis of DNA are not in
dispute. The dispute arises in the conclusion that all life must have
arisen through slow speciation coming from a single common ancestor
(atheistic) versus much life evolved to a certain extent from multiple
common ancestors (my view).

Can you put some meat on that bone? Give, say, three examples of your
"multiple common ancestors". Give a part of the tree of living
relationships that you believe has a common ancestor, and some "close"
apparent relatives that aren't related. Like for example, if you
believe all canines have one single common ancestor, say so -- say
"dogs, wolves, coyotes, and foxes have a common ancestor separate from
bears or cats", for example. Then we'll discuss the evidence that
leads to your conclusion, and contrast it with the evidence for common
ancestry.

You actually suggested a good place to start - canines (dogs, wolves,
coyotes, and foxes). This "kind" of life seems easier to analyze than
rodents or insects.

Why not primates instead? They're just as easy to analyze as canids, and
there are a lot more studies and a lot more data, for some reason. How
many primate ancestors are there? I'm guessing you think there's one for
Homo sapiens, separate from all the others. But what else?

And again, is it something like 1000 common ancestors? How many
separate trees are you putting eucaryotes into? How about animals?
Multicelled animals? Chordates? Vertebrates? Mammals? Primates? Apes?

Let's say 1,000 common ancestors, for now. I really don't know for
sure. It's just an initial guess to get the ball rolling.

I would rather not concern myself with plants since I know very little
about them compared to animals. If I can't get a grip on how this
multiple common ancestor theory holds up in the animal kingdom, I
certainly wouldn't be able to do so in the plant kingdom where
reproduction is much different.

Let's start with the canine tree. To begin, I'll take a guess and say
three common ancestors.

What sort of evidence would you accept that there is only one common
ancestor for all canids? I know the sort I would present. It would be
evidence for the existence of a single nested hierarchy connecting them.
Would you agree that such a hierarchy would argue in favor of a single
ancestor?

I might also suggest another proposition: would you agree that evidence
for there being a single common ancestor of a more inclusive group is
also evidence for there being a single common ancestor of the group
being discussed? That is, if there is evidence that Carnivora had one
common ancestor, would you agree that this is also evidence that Canidae
(part of Carnivora) had one ancestor?

Where would you like to draw the line?