dartagnan wrote: If you've got steps, I'm willing to hear you out.
Thankyou.
I can picture it.
Good. I have no way of knowing if you have the correct picture but lets go.
But I sense you're doing what some have already started doing.
No way, I haven't mentioned religion and I may not need to.
Just stay with me.
The picture takes time as the upward direction. This is standard space-time visualization. Is is extremely simplified just to make some philosophical points. That needs to be clear.
In the analogy, only what is at a certain altitude is visible. That is the present. But the horizontal 2-dimensional plane is not supposed to be space literally. It is to stand in for the extremely high dimensional space of all possible instruction sets or if you like to the body plans which are the expression of those genes. There is much unused space for two reasons. 1) Most instructions sets are nonsense. 2) Not all possible viable instruction sets are actually extant. I have added in the idea of the branched having differently shaped cross sections as an extra aid to imagination but it is really the position in this large space of possibilities)
Now, since each little island appears unique and of lower dimension than it real is (indeed it is unique at that altitude---(read: point in history))) and humans be as they are, these shapes become familiar and are part of what we expect to see in the world. We categorize and try to pigeon hole the world naturally. We all do it.
These shapes may even seem inevitable, essential or even eternal like numbers or geometric shapes. They do seem unchanging. That’s an elephant shape, that’s a cat, that’s a chicken etc.)
Now imagine that if someone comes along and says that there is a branching structure and that if we could lower the plane of visibility (move backwards in time) we would see these shapes change (and their locations is shape space) move around. But every now and then they come together as we move back in time (downward in the picture). That’s because of the branching.
Now our own little shape is our won and so it the point of reference. We seem so special and familair, we seem beautiful to ourselves.
A Rat Terrier is more different from a Great Dane than any human is in appearance from an ape. But to us it seems a large difference.
Sufficiently different primates always seem ape-ish. It’s a prejudice on our part but perhaps a good one (perhaps it would be bad for our health and solidarity if we tried to mate with them)
Now back to the analogy.
As we move back we see that our shape has a history and there was a branching event. Was there a first human or first primate on our branch? No! Not if you look at the tiny scale. At the small time scale all sorts of details appear and it is hard to say what was the first instance representing that branch. The branch itself is a fuzzy mess if we include individuals in the picture rather than just types of individuals
But at that point the shapes would have looked ape-like to us and to any other modern primate would have looked just as strange. But we group all these as ape-like by habit of thought. To us they all look pretty nonhuman.
Moving down further we see lots of these branching points.
Now come back up to the present. Would you look at another branch, say that of a modern ape, and ask why doesn't that branch turn into this branch? Huh? Now that doesn't even make sense. Why would the branches, free to meander under the pressure of natural selection, meandering through a space of unimaginable dimensions somehow come to the same point in "shape space"? Even for a tree where there are only two dimensions at each level, you almost never (or never) see branches coming together to make one branch. Even if it happened it would happen at another location in shape-space so that So to ask why apes don’t evolve into humans is like the above backward branching coincidence. Could they come together again? Why would they, there is an infinity of things to evolve toward and in the mean time we are evolving too.
So when we view evolutions as a branching in a space of possible body plans of extremely high dimension then there is no reason to think that the human form is inevitable or to expect other primates to be funneled toward that body plan. In fact, it is essentially impossible for probablistic reasons (unless thereare what we marthematiciansd would call unexpected
attractors)
Evolution is not a line of body shapes marching forward, it is a highly complex branching process through a high dimensional set of possibilities. So very complex it could not really be pictured in detail.
Now for the religion:
The tree of life turns out to be far more glorious and numinous that one might have thought. So rejoice with other Christian biologists like Ken Miller.
when believers want to give their claims more weight, they dress these claims up in scientific terms. When believers want to belittle atheism or secular humanism, they call it a "religion". -Beastie
yesterday's Mormon doctrine is today's Mormon folklore.-Buffalo