Replies

annalex: "The offsprings of interbreeding survive to maturity and are themselves capable to breed..."

I have cited before examples of evolution "caught in the act" of speciation -- half way in the middle of forming a new "species boundary" (your term) which prevents them from producing viable offspring.
Of the three species of Zebras, to repeat, two can produce viable hybrids, but the third cannot -- at least not consistently.
Attempts to interbreed produce unusually high levels of miscarriage and still births.

Might some of those Zebra hybrid offspring be viable?
I don't know, but this example clearly illustrates the point that speciation in nature is not a simple matter of one mutation crossing a "species boundary".
Rather, it's the accumulation of many mutations, generation after generation, which leads to a long process among separated sub-groups of increasing difficulty in interbreeding.

So, using your term, a "species boundary" is what forms whenever sub-groups accumulate so many different mutations they cannot produce viable offspring.
By scientific definition then, where there was one species, now there are two, and this is illustrated in countless natural examples.

annalex: "For example, if evolution from species proper to another species proper occurs in specially chosen climate and with artificial insemination... "

Your term "species proper" is meaningless.
The scientific definition of "species" includes the ability to interbreed in nature.
When two different sub-species no longer interbreed, then they are classified by science as two separate species.
So that is your "species boundary."
And the ability of sub-species to interbreed is largely a function of the number and type of DNA mutations which accumulate generation by generation, typically over thousands or millions of generations.

Of course, simulating thousands or millions of generations in large creatures in a lab is impossible in real time.
And not necessary to confirm Evolution Theory, since we can see, through DNA analysis, exactly which mutations separate one group from another.

annalex: "Well, it would depend of what kind of evolution you set out to prove.
If you are proving the evolution with random mutations..."

I don't personally believe that anything is ever truly random, but rather God at some level directs everything.
Exactly where, how and why we will never really know, but the appearance of randomness in nature is one just tool God uses to enact His will, in my humble opinion.

So it's ultimately irrelevant to me exactly how "random" various mutations may or may not have been.
However, you have to ask this question: if God wishes for things to appear "random", would He not in His infinite wisdom have created them to actually be random?

In reference to alleged "randomness", I would invite you to look up the mathematical ideas in chaos theory, and particularly the notion of a "strange attractor".
In that language of directed randomness, God is the Great Attractor, who makes what appears random conform to His plans for the Universe.

That is my theological belief, and it leads me to suspect that we will never find scientifically the "Hidden Hand of God" within the "random" mutations that created all life on Earth, and eventually, us.
That's why as far as science is concerned, by definition of the word "science" these DNA changes were all just "random".

And I have no problem with that -- let scientists do their scientific "thing", as long as it's honest work, it's all good stuff as far as I'm concerned.

annalex: "If, however, you want to prove a weaker hypothesis: that evolution is possible if someone directs it..."

That is hardly a "weaker hypothesis", it's a confirmed fact as demonstrated by innumerable examples of humans working to develop new breeds for agricultural and other purposes.
Selective breeding and careful hybridization alone produce astonishing new varieties, and there is no imagining what might eventually result from DNA engineering.
So "directed evolution" is not a "hypothesis", its a fact.

annalex: "direct observation of mammals and birds is that their species are stable: you can only produce examples of speciation by fudging the definition of species, and at any rate you can only point to very similar animals.
It ix natural to conjecture, as I do, that species proper do not evolve one to another at all: there is a boundary that does not get crossed. "

As now demonstrated many times, all of that simply is not true:

Species are not necessarily "stable", they "descend with modifications" in every generation, and each small modification is "approved" or "rejected" through "natural selection."
Those are facts, there's nothing even "hypothesis" about it.
Examples of speciation are everywhere in nature, and you only ignore them by pretending to reinvent the scientific definition of the word "species".
And then you accuse me of "fudging".
Actually, you have no serious definition of "species" and it is you who "fudges" to make your imaginary "species boundary" seem real.
Of course I "point to very similar animals", because that is precisely where any new speciation must necessarily happen.
Your "species boundary", by whatever reality it has, only forms when two previously interbreeding sub-species become so different they can no longer interbreed -- dare I say it? They become biologically divorced.
Now you have a new species, and a new relatively weak "species boundary", however firmly-fixed it might much later become.
"there is a boundary that does not get crossed".
New sub-species, species and genera are formed continually in nature, in the case of species whenever two sub-species evolve to the point they no longer successfully interbreed.
That is not a fixed "boundary line", but rather a slow process of increasing difficulty to interbreed, of which many examples should be readily apparent.

annalex: "If evolution were real science you would not need to psychoanalyze your opponents.
You would simply use facts and logic."

When you claim science is a "cult" and working scientists are "cult authorities" then you have left the reservation of sanity, and entered the realm of psychoanalysis -- tell us poor dear, what is your problem, did some scientist drop you on your little head as a child, and that's why you can't think logically any more?

That is all language of disrespect, regarding which a certain wise Individual once directed we should "do unto others...", FRiend. ;-)

this example [with three breeds of zebras, one claimed to be a separate species] clearly illustrates the point that speciation in nature is not a simple matter of one mutation crossing a "species boundary".

I did't not say it was simple. If your third breed of zebra eventually retains the ability to produce viable offspring and a stable colony within that breed, and completely loses the ability to interbreed with both other two in a lab setting, you will have speciation. So far, you have a breed that is distant from other two, but still the same genome, since interbred offspring is possible.

When two different sub-species no longer interbreed [in nature], then they are classified by science as two separate species.

So that "scientific" definition cannot be used to define the boundary (it is also logically meaningless because it depends on sexual behavior rather than on the genome). I defined the boundary that, I postulate, does not get crossed differently. Deal with it.

my theological belief

The point remains that there are two experiments possible, one with random mutations (for example using a lottery machine) and the other with directed mutations. Each will be useful to turn evolution into something resembling science, but each will prove a different thing compared to the other.

humans working to develop new breeds

Breeds, yes. Species, no, at least not species in the sense I prefer to use the term. Please pay attention to the matter being discussed.

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Repeating your fantasies does not constitute a proof from observation. Breeds are fluid, species are not.

you claim science is a "cult"

I don't. I love, understand, and respect science. Evolution is not science. Once upon a time, -- when genetics were not known, roughly at the time of Darwin, -- it was a plausible scientific hypothesis, made in absence of real knowledge. Now, it is nothing but a cult. One of the characteristic of a cult is that it uses camouflage to look like something respectable, in this case, to look like science. Another is that the arguments are not done straight: for example, the same questionable claim (that breeding is speciation) is repeated as if it is not in dispute. And here you try to slander me as an enemy of science. Please find on this thread where I called science a cult, or retract your slander.